The Abdomen - Week 3 PDF

Pelvis is the part of the trunk inferoposterior to the abdomen, with the pelvic cavity being the inferiormost part of the abdominopelvic cavity The pelvic cavity is funnel shaped and it contains the terminal parts of the ureter, the urinary bladder, the rectum, the pelvic genital organs, the blo...

Pelvis is the part of the trunk inferoposterior to the abdomen, with the pelvic cavity being the inferiormost part of the abdominopelvic cavity The pelvic cavity is funnel shaped and it contains the terminal parts of the ureter, the urinary bladder, the rectum, the pelvic genital organs, the blood vessels, lymphatics and nerves The pelvic cavity is limited inferiorly by the musculofascial pelvic diaphragm, which is suspended above but descends centrally to the level of the pelvic outlet The pelvic cavity is bounded posteriorly by the coccyx and inferiormost sacrum, with the superior part of the sacrum forming a roof over the posterior half of the cavity The bodies of the pubic bones and the pubic symphysis uniting them to form an anterior-inferior wall that is much shallower and shorter than the posterior superior wall and the ceiling The axis of the pelvis, which is a line in the median plane defined by the center point of the pelvic cavity The whole pelvic girdle is part of the lower limbs appendicular skeleton The greater pelvis is surrounded by the superior pelvic girdle, occupied by the inferior abdominal viscera The lesser pelvis is surrounded by the inferior pelvic girdle The perineum is a the surface of the trunk between the thighs and the buttocks, and the shallow compartment deep to this area but inferior to the pelvic diaphragm -- this includes the anus and external genitalia The pelvic girdle is basin shaped and its function is to bear the weight of the upper body when sitting or standing, transfer weight from the axial to the lower appendicular skeleton for standing and walking and to provide attachment for the LE muscles and abdominal wall muscles The pelvic girdle is made up of the fusion of three bones: the ilium, ischium and pubis. There is also the sacrum and coccyx (but not a part of the fusion) The ischium, ilium and pubis all fuse after puberty to form what we call the hip bone The right and left hip bones are joined anteriorly by the pubic symphysis, which is a secondary cartilaginous joint. And posteriorly by the sacroiliac joints to form the full girdle The ilium is the superior fan shaped part of the hip, this bone takes part in the formation of the acetabulum, which is the hip socket, the iliac crest and the concavity of the wings, the iliac fossa Posteriorly the sacropelvic surface features an auricular surface and an iliac tuberosity The ischium has a body and a ramus. The body helps form the acetabulum. The ramus forms part of the obturator foramen which has a protuberance in that region called the ischial tuberosity and another important segment called the ischial spine The pubis is an angulated bone with a superior ramus, which also helps form the acetabulum. And it has an inferior ramus that contributes to the borders of the obturator foramen There is a thickening in the anterior end of the pubis called the pubic crest which ends laterally as the pubic tubercles The pubic arch is formed by the right and left ischiopubic rami that meet at the pubic symphysis The inferior borders of the pubic arch define the subpubic angle. The angle is much more acute in biologic males (80 degrees The pelvic inlet tends to be heart shaped in males and oval and rounder in females The lesser or true pelvis is going to carry a lot more significance gynecologically -- this is the inside of the pelvis During a pelvic exam the distance between the ischial spines is considered the narrowest part of the canal through which the baby's head must pass in childbirth -- so this is considered the most significant narrowing of the lesser pelvis Joints and Ligaments of the Pelvis: Sacro-iliac joints link the axial skeleton of the spine to the inferior appendicular skeleton The articular surfaces of the synovial joints have irregular but congruent elevations and depressions to interlock together The SI joints differ from other synovial joints in that there is only very limited mobility Anchored via the sacro-iliac ligaments ◦ the anterior are the parts of the front of the joint ◦ The interosseous sacroiliac ligaments are deep between the sacral tuberosity and the ilium Inferiorly the posterior ligaments are joined by fibers running from the posterior margin of the ilium, the lateral sacrum and the base of the coccyx to the tuberosity that is the sacral tuberous ligament The sacro-spinous ligament runs from the lateral sacrum and coccyx to the ischial spine - this is what divides the big forament into the greater and lesser sciatic foramina The pubic symphysis consists of a fiber cartilaginous interpubic disc and surrounding ligaments uniting the bodies of the pubic bone in the median plane ◦ The interpubic disk is generally wider in females and the superior pubic ligament connects the superior aspects of the pubic bodies and interpubic discs, extending as far as the pubic tubercles The inferior (arcuate) ligament is thick arch of fibers that connects the inferior joint components rounding off that subpubic angle to form the apex of the pubic arch The lumbosacral joint is the joining of L5 and S1 are joined by an IV disc along with facet joints ◦ these joints are all strengthened by an iliolumbar ligament The sacrococcygeal joint is reinforced by anterior and posterior sacrococcygeal ligaments During pregnancy the circumference of the lesser pelvis does have to increase to accommodate everything There is secretion of a hormone called relaxin, which causes the pelvis ligaments to relax in the second half of pregnancy Relaxation of especially the sacroiliac ligaments allows up to a 10-15% increase in diameter The coccyx can also move posteriorly if it needs to make room for things during pregnancy When the sacrum is pushed down, the ilium pulls inward because of the way these are structured Bony ring fractures of the pelvis are usually due to trauma and are most likley going to happen in one place Falls onto the lower extremities can cause fractures of the femoral neck or fractures of the acetabulum If the person is younger than the age of 17, the bones can break into their original three parts (ischium, ilium and pubis) Spondylolysis is a defect in which the vertebral arch is separated from the body, L5 is guilty of this -- if it occurs BL on both sides it will slip forward causing spondylolisthesis Anterio-inferior wall of the pelvic cavity is made up of the pubis and levator ani muscles The anterio-inferior wall is more of a weight bearing floor than an anterior wall. It is primarily formed by the bodies of the pubic bones and the pubic symphysis and participates in the weight bearing of the urinary bladder The lateral walls of the pelvic cavity are formed by the right and left hip bone, each of which includes an obturator foramen enclosed by an obturator membrane (which is the fleshy attachment of the obturator internae muscles that covers and pads most of the lateral walls) The fleshy fibers of each obturator internae muscles converge posteriorly and they become tendinous and become sharp laterally to pass from the lesser pelvic through the sciatic foramen, to attach to the greater trochanter of the femur The medial surface of the obturator internae muscles is covered by an obturator fascia, which is thickened centrally as a tendinous arch and provides attachment for the pelvic diaphragm The posterosuperior wall is made up of the piriformis The key ligaments are going to be the anterior sacroiliac, the sacrospinous and the sacrotuberous ligaments The piriformis muscles originate from the upper sacrum and they extend through the greater sciatic foramen and attach to the greater trochanter of the femur The piriformis muscles also house the sacral plexus nerves and they have a gap at their lower border for neurovascular structures to pass between the pelvis and the lower limb The pelvic floor is formed by the pelvic diaphragm, which consists of the coccygeus muscle and the levator ani muscles as well as their fascias The pelvic floor separates the pelvic cavity from the perineum The obturator fascia attachment divides the obturator internus muscle into a pelvic and perineal portion housing obturator nerves and vessels The coccygeus muscles originate from the lower sacrum and the coccyx, attaching to the sacrospinous ligament The levator ani, the main part of the pelvic floor, attaches to the pubic bones, the ischial spines and the obturator fascia -- it stretches across the pelvis, forming this hammock like structure with an anterior gap, which is called the urogenital hiatus The levator ani does have three parts: Puborectalis, U-shaped muscle that supports fecal incontinence Pubococcygeus which connects the pubis to the coccyx and supports the pelvic organs: ◦ Pubovaginalis / Puboprostalis ◦ Puboperinealis ◦ Pubo-analis Iliococcygeus arises from the ischial spine and contributes to the pelvic floor structure The levator ani all support the abdominal pelvic organs and they all aid in incontinence. And it contracts during activity like coughing to support the viscera and it relaxes during urination and defacation in order to allow things to flow out as they need to KNOW THIS TABLE!!! During childbirth the levator ani especially are prone to stretching and tearing which can lead to decreased support of the vagina, the bladder of the uterus, or the rectum One of the more common manifestations of this is urinary stress incontinence, which is dribbling of urine during increased pressure, like coughing or lifting If the puborectalis tears, fecal incontinence may be seen The parietal peritoneum from the abdomen continues inferiorly into the pelvic cavity but does not reach the pelvic floor -- instead it reflects on to the pelvic viscera, remaining separated from the pelvic floor by the pelvic viscera and the surrounding pelvic fascia Only the superior and superolateral surfaces of the viscera are covered by peritoneum, with only the uterine tubes being intraperitoneal LOOK AT TABLE 6.3 IN THE BLOOD - shows some of the folds and the organs within the reflections Fat between the transversalis fascia and the parietal peritoneum of the inferior part of the anterior abdominal wall allows the bladder to expand between the layers Because of this fat, it is the only site where the parietal peritoneum is not firmly bound to the underlying structures The area superior to the bladder is called the supravesicle fossa - its size depends on position and size of the bladder The pocket between the uterus and rectum is called the rectouterine pouch and it is also known as the Pouch of Douglas In males and females who have had a hysterectomy, there is a rectovesicle pouch which is between the rectum and the bladder In the area where the peritoneum comes up and over the uterus, there is a double fold what makes the broad ligament of the uterus and it runs between the uterus and the lateral pelvic wall on both sides In males, there is ureteric fold where the peritoneum passes up and over the ureter and the ductus deferens on each side of the posterior bladder (this is akin to the broad ligament in females) Connective tissue between the membranous peritoneum and the muscular pelvic walls and floor that isn't occupied by viscera is the pelvic fascia The parietal pelvic fascia is the membranous layer that lines the inner aspect of the muscles forming the walls and floor of the pelvis The visceral pelvic fascia ensheathes the pelvic organs The parietal and visceral layers are thickend where the organs penetrate the pelvic floor and the two are continuous The connective tissue between the two parietal and visceral layers is considered the subperitoneal endopelvic fascia It is a continuous of the thin endoabdominal fascia that lies between the muscular abdominal walls and the peritoneum The loose tissue fills two potential spaces, the retrorectal (also called presacral), and retropubic (also called prevesicle and paravesicle) Between the rectorectal and retropubic is a hypogastric sheath that gives passage to all the vessels and nerves passing from the lateral wall to the pelvic viscera The hypogastric sheath divides into three layers moving medially, the lateral ligament of the bladder (anteriormost), middle ligament of the bladder which forms the rectovesicle septum between the posterior bladder and the prostate in males or the vagina in females (also called the cardinal ligament in females), and the lateral rectal ligament which covers the middle rectal artery and vein (most posterior) The major neurovascular structures of the pelvis lie extraperitoneally against the posterolateral walls The somatic nerves lie laterally adjacent to the walls and the vascular structures medially to them Generally the veins are lateral to the arteries and the pelvic lymph nodes are mostly clustered around the pelvic veins, the lymphatic draining often paralleling venous flow Gonadal artery - comes off the abdominal aorta and courses retroperitoneally into the suspensory ligament in females or through the inguinal canal in males -- it supplies the abdominal ureter as well as the testes and the epididymis or the ovary and the ampullary end of the uterine tube. It anastamoses with the cremasteric artery and the artery of the ductus deferens in males and the uterine artery in females In females, the close proximity to the ureters is of surgical concern The superior rectal artery is a continuation of the IMA and it crosses the left common iliac vessels and descends into the pelvis between layers of sigmoid mesocolon and supplies the superior part of the rectum and anastomoses with the middle rectal artery and the inferior rectal artery The medial sacral artery originates from the posterior aspect of the abdominal aorta and descends close to the midline over the L4, L5 vertebrae, the sacrum and the coccyx and it supplies the inferior lumbar vertebrae, the sacrum and the coccyx -- it anastomoses with the lateral sacral artery The internal iliac originates from the common iliac artery and it passes medially over the pelvic brim and descends into the pelvic cavity, often forming anterior and posterior divisions. The main blood supply to the pelvic organs, gluteal muscles and the perineum comes from this right here The anterior division of the internal iliac passes anteriorly along the lateral wall of the pelvis and it divides into visceral obturator and internal pudendal arteries -- it supplies the pelvic viscera, muscles of the superomedial thigh and the perineum The umbilical artery originates from the anterior division of the internal iliac artery, and it runs a short pelvic course, giving off superior vesicle arteries and then it obliterates becoming the medial umbilical ligament. It supplies the superior aspect of the urinary bladder and in some males it supplies the ductus deferens via the superior vesicle artery and the artery to the ductus deferens The superior vesicle arteries originate from the patent proximal umbilical artery and they pass to the superior aspect of the urinary bladder. And in some males they also give off the ductus deferens via the artery to the ductus deferens -- these anastomose with the inferior vesicle artery in males and with the vaginal artery in females The obturator artery originates off the patent proximal umbilical artery and it runs anteroinferiorly on the obturator fascia of the lateral pelvic wall and exits the pelvis via the obturator canal -- it will supply pelvic muscles and is a nutrient artery to the ilium, the head of the femur and the muscles of the medial compartment of the thigh The obturator artery anastamoses with the inferior epigastric artery via the pubic branch and the umbilical artery You can get an aberrent or an accessory obturator artery in about 20% of people -- it arises from the inferior epigastric artery instead and it descends into the pelvis along the usual route of the pubic branch -- so it does not go down into the same foraminal area that we would recognize if you have an obturator muscle If you have an obturator artery and have the other one that comes off the inferior epigastric, this is called an accessory obturator artery If you do not have the main obturator artery and all you have is the one off the inferior epigastric then this is called an aberrant obturator artery The inferior vesicle artery also from that patent umbilical artery and it only important in males because the inferior bladder gets supplied by the vaginal artery in females The inferior vesicle artery is going to pass superior sub-peritoneally into the lateral ligament of the bladder and give rise to the prostatic artery and occasionally the artery to the ductus deferens. This also supplies part of the prostate, the seminal glands and part of the ureter and it anastomoses with the superior vesicle artery The inferior vesicle artery occurs consistently as a direct branch of the anterior division only in males and in females it can occur with 50/50 frequency as a direct branch of the internal iliac artery or as a branch of the uterine artery The artery to ductus deferens originates from either the superior or inferior vesicle artery and it anastomoses with the testicular artery because it is supplying the ductus deferens There are also prostatic branches that originate from the inferior vesicle artery The uterine artery originates from the inferior vesicle artery and it runs anteromedially in the base of the broad ligament (the superior cardinal ligament), and it gives rise to the vaginal artery to supply the lower bladder. it will then cross the ureter superiorly to reach the lateral aspect of the uterine cervix and it supplies the uterus, the ligaments of the uterus the medial parts of the uterine tube and ovary and the superior vagina via the vaginal branches The uterine artery will anastomose with the ovarian artery via tubal and ovarian branches The vaginal artery originates from the uterine artery typically and is going to descend to and arborize around the vagina and pass some branches to the urinary bladder. It supplies the vagina, the vestibular bulb and the adjacent rectum and then the inferior bladder as well The internal pudendal artery originates from the anterior division of the internal iliac artery as well. It exits the pelvis via the greater sciatic foramen, inferior to the piriformis, and entering the perineum via the lesser sciatic foramen and will pass through the pudendal canal to the urogenital triangle. This is the main artery of the perineum, including muscles and skin of the anal and urogenital triangles and the erectile bodies. It anastomoses with the umbilical artery and the prostatic branches of the inferior vesicle artery in males The middle rectal artery originates from the anterior division of the internal iliac artery and descends in the pelvis in the inferior part of the rectum The inferior gluteal artery originates from the anterior division of the internal iliac artery and exits the pelvis via the greater sciatic foramen, inferior to the piriformis and it will supply the pelvic diaphragm, the piriformis, the quadratus femoris the superior most hamstring, gluteus maximus and the sciatic nerve This anastamoses with the profundafemoris artery The posterior division of the internal iliac is going to pass posteriorly and give rise to some parietal branches and supply the pelvic wall in the gluteal region iliolumbar artery originates from the posterior division of the internal iliac artery and it ascends anterior to the SI joint and posterior to the common iliac vessels and the psoas major to supply the psoas major, the iliacus, the QL and also the cauda equina to an extent The lateral sacral branch also comes off the posterior division of the internal iliac artery and it runs on the anteromedial aspect to the piriformis to send branches into the pelvic sacral foramina. it supplies the piriformis as well as structures in the sacral canal, the erector spinae and some of the overlying skin The superior gluteal artery also originates from the posterior division of the internal iliac artery and it passes between the lumbosacral trunk and the anterior ramus of the S1 spinal nerve to exit via the greater sciatic foramen superior to the piriformis. This also supplies the piriformis as well as the three gluteal muscles and the TFL -- it anastomoses with the lateral sacral, the inferior gluteal, the internal pudendal, the deep circumflex femoral and the lateral circumflex femoral arteries The internal iliac artery in general is the principal artery of the pelvis and it supplies most of the blood to the pelvic viscera and to some of the MSK part of the pelvis. It also supplies branches to the gluteal region, the medial thigh and the perineum If the internal iliac becomes stenotic for any reason, collateral pathways of anastomosing arteries can support the blood (lumbar and iliolumbar anastomoses, medial sacral and lateral sacral anastamoses, superior rectal and middle rectal anastomoses, inferior gluteal and profunda femoris anastomoses) The pelvic venous plexuses are formed by interjoining veins surrounding the pelvic viscera. Rectal, vesical, prostatic, uterine, and vaginal plexuses all unite to drain by tributaries of the internal iliac veins, though some do drain into the superior rectal vein into the inferior mesenteric vein of the hepatic portal system Lymph nodes are variable and often grouped somewhat arbitrarily: External Iliac Lymph Nodes: receives drainage from the inguinal lymph nodes, draining into the common iliac lymph nodes Internal iliac lymph nodes: receive drainage from the inferior pelvic viscera, deep perineum, the gluteal region, draining from the common iliac nodes The sacral lymph nodes receive drainage from the postero-inferior pelvic viscera and drain either into the internal or common iliac nodes Common iliac lymph nodes: act as a common route for drainage to the lumbar nodes, but may get some drainage from the neck of the bladder and the inferior vagina In most people the superior rectal vein is the biggest contributory to the inferior mesenteric vein, except in pregnancy -- the uterine vein becomes a bigger contributor The pelvis is innervated mainly by the sacral and coccygeal spinal nerves, and the pelvic part of the ANS The piriformis and coccygeus muscles form a bed for the sacral and coccygeal nerve plexuses The obturator nerve arises from spinal nerves L2-L4 of the lumbar plexus in the abdomen and it enters the lesser pelvis and runs in the extraperitoneal fat along the lateral wall of the pelvis to the obturator canal As the obturator nerve passes through the canal and enters the thigh, it divides into anterior and posterior parts that supply the medial thigh muscles -- there are no pelvic structures supplied by the obturator nerve The obturator nerve is especially vulnerable during surgery, which leads to painful spasms of the medial thigh muscles or sensory deficit if its damaged at or immediately superior to the pelvic brim At the superior part of the descending rim, the L4 nerve unites with the anterior ramus L5 nerve to form the thick, cord like, lumbosacral trunk LEARN THE LOCATION AND THE ORIGIN OF THESE NOW AND DISTRIBUTION TO THE PELVIS BIG TWO ARE THE SCIATIC AND PUDENDAL NERVES Sciatic nerve is the largest nerve in the body and is the large anterior rami of spinal nerve L4-S3 converged on the anterior surface of the piriformis The sciatic nerve passes through the great sciatic foramen The pudendal nerve is the main nerve of the perineum and it is the chief sensory organ of the external genitalia. It is accompanied by the internal pudendal artery and it leaves the pelvis through the greater sciatic foramen in between the piriformis and the coccygeus muscles, it then hooks around the sacral spine and sacrospinous ligament and enters the primary perineum back again through the lesser sciatic foramen The nerve to the levator ani branches off the pudendal nerve and may be stretched and damaged during childbirth There is a coccygeal plexus that is a small network for S4-S5 anterior rami as well as the coccygeal nerves. It lies on the pelvic surface of the coccygeus and supplies that muscle and then part of the levator ani The anacoccygeal nerves arise from the coccygeal plexus and pierce through the coccygeus to supply a small area of skin from the tip of the coccyx and the anus LOOK AT BOOK TO SEE THE PELVIC AUTONOMIC NERVES AS WELL THERE ARE 4 DIFFERENT ROUTES Visceral afferent innervation changes based on whether the nerve is inferior or superior to the pelvic pain line this line corresponds to the inferior limit of the peritoneum Intraperitoneal abdominopelvic viscera or aspects of visceral structures that are in contact with the peritoneum are superior to the pain line Superior to the pain line, the afferent fibers follow sympathetic fibers retrograde Inferior to the pain line, the afferent fibers follow the parasympathetic fibers retrograte into the spinal sensory ganglia of S2-S4 SUPERIOR IT GOES WITH SYMPATHETIC NERVE AND INFERIOR IT IS WITH PARASYMPATHETIC NERVES Urinary Organs: Pelvic portions of the ureters: ◦ as the ureters cross the bifurcation of the common iliac artery or the start of the external iliac artery, they are going to transition from the abdomen and into the lesser pelvis ◦ in the pelvis, the ureters run along the lateral walls parallel to the anterior margin of the greater sciatic notch situated between the parietal pelvic peritoneum and the internal iliac arteries near the spine ◦ Near the ischial spine, they are going to curve, anteromedially, above the levator ani and into the urinary bladder ◦ The lower ends of the ureters are supported and surround by the vesicle venous plexus ◦ The ureters do pass obliquely through the muscular wall of the bladder, creating a one-way flat valve that prevents urine from going backwards ◦ This pressure, combined with the internal pressure of the filling bladder, collapses the intramural section of the ureter, and urine is going to move down the ureters via peristaltic contractions, transporting a few drops every 12-20 seconds ◦ In males, the ductus deferens is the only structure that passes between the ureter and the peritoneum. It crosses the ureter within the ureteral fold within the peritoneum with the ureter lying posterolateral to it ◦ In females, the ureter passes immediately to the origin of the uterine artery and it continues to the ischial spine, where is it crossed by the uterine artery, and then travels close to the lateral part of the vaginal fornix before entering the bladder ◦ There is variable arterial supply to the pelvic portions of the ureters, with branches from the common iliac, internal iliac, and ovarian, anastomosing and causing a continuous supply ◦ The ureters are innervated by the autonomic plexuses and are superior to the pelvic pain line, with afferent fibers reaching spinal ganglia and cord segments T10-L3. Uteretic pain is usually referred to the ipsilateral lower quadrant of the abdomen or groin The urinary bladder: ◦ The urinary bladder is a hollow organ with strong, muscular walls and it is highly distensible and serves as a temporary reservoir for urine. When it is empty, the adult bladder is located in the lesser pelvis, particularly above and behind the pubic bones, and it lies mostly beneath the peritoneum, resting on the pubic nones and surfaces in front of the prostate in males or the anterior wall of the vagina in females ◦ The bladder is freely moveable within the extra peritoneal tissue, except for at the neck, which is anchored by the lateral ligament of the bladder and the tendinous arch of the pelvic fascia ◦ In infants and young children, the bladder is almost entirely in the abdomen and descends into the greater pelvic by age six and into the lesser pelvis by puberty ◦ The bladder is tetrahedral when empty, with an apex, a body, a fundus and a neck. It has four surfaces, an anterior and posterior and two inferolateral ◦ The apex of the bladder points towards the pubic symphysis and the fundus forms a posterior wall, the body is between the apex and the fundus and the neck is where the fundus and inferolateral surfaces meet ◦ The bladder bed consists of structures in direct contact with it, the pubic bones, the fascia over the levator ani, and the superior obturator internus muscle ◦ Only through the superior surface of it is actually covered by peritoneum. ◦ In males, the fundus of the bladder is separated from the rectum by the rectal vesicle, septum and seminal glands ◦ In females, the fundus of the bladder is adjacent to the anterior vaginal wall and the bladder is involved by loose connective tissue fascia ◦ The bladder walls are mainly made up of what is called detrusor muscle and in males the muscle fibers of the bladder neck form the internal urethral sphincter, which prevents semen  backflow during ejaculation and in females, these fibers continue with the urethral wall muscles ◦ In ureteric and internal urethal orifices, they form the trigone of the bladder, so it makes a triangle shape between the two internal urethral orifices and the ureteric orifice ◦ The ureteric orifices surround the detrusor muscle loops and they prevent urine backflow into the ureters when the bladder contracts. ◦ The uvula of the bladder, which is a slight elevation in the trigone of the bladder, is more prominent in older men due to prostate enlargement ◦ The urinary bladder is mainly supplied by the branches of the internal iliac arteries, with the superior vesical arteries supplying the anterosuperior part and the inferior vesical or the vaginal supplying the fundus and neck ◦ Parasympathetic fibers from the pelvic splanchic nerves are motor to the detrusor muscles and they are inhibitory to the internal urethral sphincter of the male bladder ◦ The superior bladder is superior to the pelvic pain line ◦ When visceral afferent fibers are stimulated by stretching, the bladder will contract reflexively, and the internal urethral sphincter relaxes in males and urine flows into the urethra ◦ With toilet training, we learn to suppress that reflex when we don't wish to accidentally void ◦ The sympathetic innervation that stimulates ejaculation simultaneously causes contraction of the internal urethral sphincter to prevent reflux of semen into the bladder ◦ This also occurs at sympathetic responses other than ejaculation in moments of self- consciously when waiting at the urinal to go pee, can cause the internal sphincter to contract hampering the ability to urinate until parasympathetic inhibition of the sphincter occurs ◦ Damage to the anterior part of the anterior abdominal wall can distrupt the bladder when the bladder ruptures it will also tear the peritoneum so you will end up with extravesation which is urine into the pelvic cavity The Urethra: The male urethra is a muscular tube that conveys urine from the internal urethral orifice to the external urethreal orifice FIND THE IMAGE ON THE DIFFERENT PARTS OF THE URETHRA The intramural (preprostatic parts) of the urethra, changes in diameter in length depending on whether the bladder is filling or empty -- when the bladder is filling, the neck of the bladder is tonically contracting, making the internal urethral orifice small and high -- during emptying, the neck of the bladder relaxes, causing the orifice to widen and lower. in the prostatic urethra, the most notable feature is the urethral crest, which is a median ridge flanked by the prostatic sinuses, the secretory ducts of the prostate open into the sinuses The seminal colliculis, which is a rounded eminence of the urethral crest has a slit like orifice that leads into the prostatic utricle, which is a vestigial remnant of the embryonic uterovaginal canal The ejaculatory ducts open into the prostatic urethra near the surface of the prostatic utricle, and merges in the urinary and reproductive tracts LOOK AT AN IMAGE IN A SAGITTAL CUT intramural and prostatic parts are supplied by prostatic branches of the inferior vesical and middle rectal arteries The female urethra passes antero-inferiorly from the internal urethral orifice of the urinary bladder to the external urethral orifice the internal pudendal and vaginal arteries supply it The rectum is continuous with the sigmoid colon and the anal canal The rectum has a number of flexures: sacral flexure: from following the curve of the sacrum and coccyx Lateral flexures: formed in relation to transverse rectal folds, two on the left and one on the right Anorectal flexure: occurring as the gut perforates the pelvic diaphragm The dilated terminal portion is called the ampulla of the rectum and can relax to accommodate the initial and subsequent arrivals of fecal material The rectum is covered anteriorly and laterally on the superior third of the rectum by peritoneum only the anterior on the middle third, and it is subperitoneal on the inferior third The superior rectal artery is a continuation of the IMA and it supplies the upper portion of the rectum The middle rectal arteries are branches from the anterior division of the internal iliac arteries and they supply the middle and lower portions of the rectum The inferior rectal artery originate from the internal pudendal arteries in the perineum and they supply the anarectal junction and the anal canal While there are anastomoses between the superior and inferior rectal arteries, connections with the middle rectal arteries are pretty minimal Blood from the rectum does drain through the superior, middle and inferior rectal veins and there are anastomoses between the portal and systemic veins in the anal canal and they are significant for portacable anastamoses (places where you can bypass the portal system to get to the IVC) The superior rectal vein drains into the portal system, while the middle and inferior drains into the systemic system (IVC) The rectal venous plexus surround the rectum and connects with the vesicle venous plexus in males and the uterovaginal venous plexus in females Although termed rectal, some of these rectal plexuses are really associated with the anal canal in terms of function and clinical relevance The nerve supply to the rectum comes from both the sympathetic and PS system: Sympathetic nerves OG from the lumbar spinal cord and they travel through the lumbar splanchnic nerves, the hypogastric pelvic plexus, and the periarterial plexuses of the inferior mesenteric and superior rectal arteries PS nerves OG from the S2 - S4 spinal cord levels The rectum is below the pelvic pain line, so all visceral afferent fibers follow that PS pathway back to the S4 spinal ganglia A lot of structures are palpable through the walls of the rectum so during a rectal exam, the prostate, cervix, enlarged iliac nodes, pathological urethral thickening, anal fossa abscesses, and even an inflamed appendix are sometimes palpable The anastomoses between the superior, middle and inferior rectal veins create important communications between the portal and systemic venous systems. The superior rectal vein drains into the inferior mesenteric vein. While the middle and inferior rectal veins drain into the IVC through the systemic surface system An abnormal increase in pressure within the valveless portal system, or trunk veins, can cause the superior rectal veins to enlarge, leading the internal backflow or stasis in the internal rectal venous plexus -- this is particularly relevant in conditions like portal HTN, often associated with hepatic cirrhosis -- you can get internal hemorrhoids from having an internal venous blockage You can get varicosities without having internal hemmorhoids (blockages) The ductus deferens is a continuation of the duct of the epididymis and it has thick muscular walls and a small lumen, giving it a firm, cord like feel The ductus deferens begins at the tail of the epididymis at the lower end of the testes and then ascends behind the testes and medial to the epididymis, becoming the main component of the spermatic cord Within the pelvis, the ductus deferens runs along the lateral pelvic wall, lying external to the parietal peritoneum and it ends by joining the duct of the seminal gland to form the ejaculatory duct Throughout its pelvic course the ductus deferens is in direct contact with the peritoneum with no other structures in between them near the posterolateral angle of the bladder the ductus deferens crosses above the ureter, running between the border and the peritoneum of the ureteral fold to reach the bladder's fundus this relationship is somewhat similar to the description of the uterine arteries position relative to the ureter in females behind the bladder the ductus deferens lies first above the seminal gland and then it descends medially to both the ureter and the gland. At that point it then enlarges to form the ampulla of the ductus deferens before terminating. If you have a deferentectomy, also called a vasectomy, the ductus deferens is ligated or excised through the superior scrotum -- unexpelled sperms generate in the epididymis and the proximal ductus deferens Each of the seminal glands are elongated about 5 CM, located between the bladder's fundus and the rectum. They are positioned obliquely above the prostate and they do not store sperm despite the term vesicle -- instead they secrete a thick alkaline fluid containing fructose and a coagulating agent -- this fluid mixes with the sperm as they pass through the ejaculatory ducts into the urethra The upper ends of the seminal glands are covered with peritoneum and lie behind the ureters and the lower ends are closely related to the rectum and are only separated from it by the rectovesical septum The duct of each seminal gland joins each seminal gland joins each ductus deferens to form the ejaculatory duct You can get abcesses in the seminal glands and they can be palpated rectally, especially when the bladder is full -- common in gonorrhea The ductus deferens receives a tiny artery from the superior vesicle artery that terminates by an anatomosing with the testicular artery The seminal glands receive arteries from the inferior vesicle and the middle rectal arteries The ejaculatory ducts are slender tubes about 2.5cm long and they are formed by the union of the ducts with the seminal glands with the ductus deferens These ejaculatory ducts arise at the neck of the bladder and they are going to run close together passing anteroinferiorly through the posterior part of the prostate -- they converge and open on the seminal colliculus via a tiny slit like apertures or just within the opening of the prostatic utricle Although the ejactulatory ducts pass through the prostate, prostatic secretions do not mix with the seminal fluid until after the ducts terminate in the prostatic urethra Arteries to the ductus deferens supply the ejaculatory ducts as well The prostate measure about 3 cm long, four cm wide and 2 cm deep It is the largest accessory gland in the male reproductive system and it is walnut sized The prostate is composed of 2/3 glandular tissue and 1/3 fibrous muscular tissue The prostate is encased in a dense NV fibrous capsule that includes the prostatic plexus of veins and nerves and is surrounded by the visceral layer of pelvic fascia forming a fibrous prosthetic sheath key features of the prostate are a base, which is closely related to the neck of the bladder, and apex which is in contact with the fascia on the superior aspect of the urethral sphincter and the deep perineal muscles, an anterior surface which is mostly muscular, and a posterior surface which is closely related to the ampulla of the rectum and the inferolateral surfaces which is related to the levator ani muscles The isthmus of the prostate also known as the commissure of the prostate or historically the anterior lobe, lies anterior to the urethra -- it is primarily fibromuscular and contains muscle fibers that extend from the external urethral sphincter muscle to the neck of the bladder with little to no glandular tissue The right and left lobes of the prostate are separated anteriorly by the isthmus, and posteriorly by a shallow central longitudinal furrow Each right and left lobe can be divided into four lobules Clinicians will divide the prostate into peripheral and central zones with the central zone corresponding to the middle lobe of the prostate The prostate contains 20-30 different ducts that open into the prostatic sinuses on either side of the seminal colliculis on the posterior wall of the prostatic urethra Prostatic fluid, a thin milky secretion, constitutes about 20% of semen volume, and it plays a crucial role in activating sperm If the prostate is enlarged in prostatic hypertrophy, patients may experience constriction of the urethra that runs within it, leading to nocturia, dysuria, and urgency -- this also increases the risk of UTIs DRE is still the best way to examine for the hypertrophy, though sensitivity is based on the user Prostatic arteries come from branches off the internal iliac The bulbo-urethral glands are two pea sized glands that are known also as Calper's glands, and they are located PL to the intermediate part of the urethra and they are largely embedded within the external urethral sphincter The ducts of the bulbo-urethral glands pass through the perennial membrane alongside the intermediate urethra and open into the proximal part of the spongy urethra and the bulb of the penis. These glands do secrete a mucus like fluid into the urethra during sexual arousal Female Internal Genital Organs: Ovaries are almond shaped and sized. They are the female gonads where oocytes, which are the female gametes, develop Ovaries function as endocrine glands and produce reproductive hormones Every ovary is suspended by a short peritoneal fold called the mesovarium and it is part of the larger mesenteric uterus which is called the broad ligament Before puberty the ovary is covered by a germinal epithelium. After puberty, the ovarian surface becomes progressively scarred and distorted due to repeated rupture of ovarian follicles and oocyte release during ovulation In females who take birth control that prevents ovulation, their ovaries will stay looking like the prepubital ovaries The ovarian vessels, lymphatics and nerves all cross the pelvic brim within the suspensory ligaments of the ovary -- which is a peritoneal fold that becomes continuous with the mesovarium Medially, the ovary is tethered to the uterus by a short ligament, called the ligament of the ovary, and it is the remnant of the ovarian gubernaculum of the fetus and connects to the uterus just below the uterine tube During a pelvic exam, the ovaries are typically found laterally between the uterus and the lateral pelvic wall Because the ovary is suspended in the peritoneal cavity without a peritoneal covering, the oocyte expelled during ovulation enters the peritoneal cavity and then it gets captured by the fimbraie of the uterine tubes infundibulum before they are carried into the ampulla The uterine tubes, also known as fallopian tubes, conduct the oocyte from the periovarian peritoneal cavity to the uterine cavity, providing the usual site for fertilization The fallopian tubes are about 10cm long and they lie in a narrow mesentery called the mesosalpings, forming the free anterior superior edges of the broad ligaments The fallopian tubes sit anywhere as long as they are pointing to the ovary The uterine tubes are separated into four parts from lateral to medial: 1. Infundibulum: which is the funnel shaped distal end that has the fimbriae finger like projections in order to capture the oocyte A. at least one large ovarian fimbriae is attached to the ovarian pole 2. Ampulla: widest and longest part of the tube. It starts at the infundibulum's medial end and fertilization occurs here typically. 3. Isthmus: the thick wall part that enters the uterine horn 4. Uterine part: short segment that passes through the uterine wall and opens into the uterine cavity, via the posterior uterine ostium If you sterilize a biologic female using tubal sterilization, they will put cautery rings or clips, over the distal part of the ampulla or the isthmus in order to destroy the tubes Non-surgical method of sterilization is actually inserting a nickel titanium alloy into the opening of each uterine tube (at the uterine ostium) and it scars up within three months to block and occlude the tubes Tubal pregnancies are the most common type of ectopic gestation Ectopic is when an embryo implants and begins to develop outsite the uterus -- most frequently in the uterine tube Ectopic pregnancies effects approximately 1/250 pregnancies in North America Ectopic pregnancies tend to bleed heavily and pose a significant threat to the mother's life and to the life of the embryo In some biologic females as well, you can get pus collection within the uterine tube, especially secondary to an ectopic or an underdeveloped ectopic implantation The buildup of pus in the fallopian tube causes a piousalping It is called a tubal pregnancy if it happens in the ampulla Ectopic pregnancies can occur out of nowhere and is not always because of adhesions On the right side, the appendix lies close to the ovary and the uterine tube, so it can lead to a misdiagnosis. A ruptured tubal pregnancy and resulting peritonitis can be mistaken for an acute appendicitis Both the ovarian and ascending uterine arteries terminate by bifurcating into ovarian and tubal branches, so they do not end as the ovarian and ascending uterine arteries -- they become the ovarian and tubal branches at the very end Arterial supply to both the tubes and the ovaries is from the ovarian arteries and the ascending branches of the uterine arteries The uterus and the ovaries are both intraperitoneal and therefore superior to the pelvic pain line The uterus is a pear shaped hollow muscular organ where the embryo and the fetus develop The uterus's muscular walls adapt to the growth of the fetus and provide the power for it's expulsion In a non-pregnant state, the uterus is usually situated in the lesser pelvis with its body resting on the urinary bladder and its cervix position between the bladder and the rectum Typically the adult uterus is anteverted (tipped forward and anteflexed) to sit over the bladder. When the bladder is empty it sits almost horizontally over the bladder The non-pregnant uterus is about 7.5 cm long, 5 cm wide, 2cm thick, and weighs around 90g The uterus is divided into two main parts, the body and the cervix The body of the uterus has a fundus which is the upper rounded portion above the uterine ostia. It has a vesicle and intestinal surface (vesicle being on the bladder) The isthmus is the constricted segment separating the body from the cervix in the uterus The cervix is 2.5cm in an adult, non-pregnant female, there is a supravaginal part that is between the isthmus and the vagina, and a vaginal part that protrudes into the anterior vaginal wall The vaginal portion of the cervix is typically the area that is seen during a speculum exam The cervical opening into the vagina is called the external os The uterine cavity is about 6cm from the external os of the cervix to the fundus, so this is the space between the cervix and the top of the uterus The uterine horns (L. cornua) are the superolateral regions of the uterine cavity, where the uterine tubes enter. The uterine cavity continues inferiorly as the cervical canal. The walls of the uterus consist of three layers: 1. Perimetrium - the serosa or outer layer - consists of peritoneum supported by a thin layer of connective tissue 2. Myometrium - The middle layer of smooth muscle - becomes greatly distended (more extensive but much thinner) during pregnancy A. The main branches of the blood vessels and nerves of the uterus are located in this layer B. During childbirth, contraction of the myometrium is hormonally stimulated at intervals of increasing and decreasing length to dilate the cervical os and expel the fetus and placenta C. During the menses, myometrial contractions may produce cramping 3. Endometrium - the inner mucous layer - is firmly adhered to the underlying myometrium. The endometrium is actively involved in the menstrual cycle, different in structure with each stage of the cycle. If the conception occurs, the blastocyst becomes implanted in this layer; if contraception does not occur, the inner surface of this layer is shed during menstruation The cervix contains less muscular tissue than the body of the uterus, being mainly fibrous with collagen, some smooth muscle and elastin Externally, the ligament of the ovary, attaches to the uterus posteroinferior to the uterotubal junction The round ligament of the uterus attaches anteroinferiorly to the uterotubal junction The round ligament and ligament of the ovary are remnants of the ovarian gubernaculum, related to the gonads relocation from its developmental position on the posterior abdominal wall The broad ligament of the uterus is a double layer of peritoneum extending from the sides of the uterus to the lateral walls and the floor of the pelvis -- This ligament assists in keeping the uterus in position. Laterally, the peritoneum of the broad ligament is prolonged superiorly over the vessels as the suspensory ligament of the ovary The uterine tube is in the anterosuperior free border of the broad ligament, within a small mesentery called the mesosalpinx The largest part of the broad ligament, inferior to the mesosalpinx and mesovarium, which serves as a mesentery for the uterus itself, is the mesometrium. The uterus needs both passive and active support. Dynamic support comes from the pelvic diaphragm where the tone where you are sitting and standing helps support it. The passive support to the ligament comes from these ligaments, the round ligament of the uterus, the ligament of the ovary, and the broad ligament of the uterus The cervix is the least mobile part of the uterus due to those extra ligaments and the passive support that it gets Cardinal (transverse cervical) ligaments extend from the supravaginal cervix and lateral parts of the fornix of the vagina to the lateral walls of the pelvis Uterosacral ligaments pass superiorly and slightly posteriorly from the sides of the cervix to the middle of the sacrum; they are palpable during a rectal examination. Together, both the passive and active support of the uterus keep it centered in the pelvic cavity and resist the tendency for the uterus to fall or be pushed through the vagina A hysterectomy is a surgical removal of the uterus, this is used to treat conditions like large uterine fibroids, endometriosis, or uterine or cervical cancer, this procedure can also be used to stop abnormal bleeding, menstrual periods and the ability to conceive In recent years, the frequency for non-cancerous hysterectomies has decreased as other tx options for those purposes are explored The first main surgical approach for a hysterectomy is through the anterior abdominal wall (transabdominal approach) and the second is the through the vagina (transvaginal approach) A hysterectomy can be done using conventional methods, laparascopic techniques or robotic assistants A subtotal (supracervical) hysterectomy is the top section and a radical hysterectomy is removing all of it Radical hysterectomy involves removing the ovaries along with the uterus and a subtotal hysterectomy the uterus is divided at the isthmus For a cervical or total hysterectomy the vaginal fornices are incised around the cervix to separate the uterus from the vagina and the superior end of the vagina is closed with sutures The uterine artery, which is one of the main blood supplies here to the uterus is ligated distal to the vaginal artery along with its branches to ensure maximal bloodflow to the superior end of the vagina to promote healing You only ligate the uterine artery distal to the vaginal artery so the vagina is still receiving its blood The adult vagina can be significantly distended, especially in the region of the posterior fornix. This distension allows for palpation of the sacral promontory during the pelvic exam and accomodates for the erect penis during intercourse During childbirth the vagina undergoes considerable distention, particularly anterior and posterior direction, as the fetuses shoulders are delivered Lateral distention of the vagina during childbirth is limited by the ischial spines The anatomical arrangement makes the birth canal deep in the AP direction and narrow transversely at that point, necessitating the rotation of the fetuses shoulders into the AP plane for delivery The vagina, a distensible musculomembranous tube (7–9 cm long), extends from the superiormost aspect of the vaginal part of the cervix of the uterus to the vaginal orifice, the opening at the inferior end of the vagina The main functions of the vagina are to serve as a canal for menstrual fluid, form the inferior portion of the birth canal, receive the penis and ejaculate during sexual intercourse, communicate with the cervical canal superiorly in the vestibule of the vagina inferiorly The vagina is typically collapsed with its lateral walls in contact Superior to the vaginal orifice (the opening), the anterior and posterior walls contact each other, forming a transverse potential cavity -- it is H shaped in cross-section, except for the cervix, where they are held apart because of the cervix being there The vagina lies posterior to the urinary bladder and urethra, the latter projecting along the midline of its inferior anterior wall. The vagina lies anterior to the rectum, passing between the medial margins of the levator ani (puborectalis) muscles The vaginal fornix, the recess around the cervix, includes anterior, posterior and lateral parts The vaginal fornix, the recess around the cervix, has anterior, posterior, and lateral parts. The posterior vaginal fornix is the deepest part and is closely related to the recto-uterine pouch. Four muscles compress the vagina, acting as sphincters: pubovaginalis, external urethral sphincter, urethrovaginal sphincter, and bulbospongiosus The anatomical relations to the vagina anteriorly, the fundus of the urinary bladder and the urethra laterally the levator ani and the visceral pelvic fascia and the ureters and then posteriorly, the from inferior to superior, the anal canal, rectum and rectal uterine pouch The arteries supplying the superior part of the vagina derive from the uterine arteries. The arteries supplying the middle and inferior parts of the vagina derive from the vaginal and internal pudendal arteries Only the inferior one fifth to one quarter of the vagina is somatic in terms of innervation. Innervation of this part of the vagina is from the deep perineal nerve, a branch of the pudendal nerve, which conveys sympathetic and visceral afferent fibers but no parasympathetic fibers. Making it sensitive to touch and temperature Most of the vagina (superior three quarters to four fifths) is visceral in terms of its innervation. Nerves to this part of the vagina and to the uterus are derived from the uterovaginal nerve plexus, which travels with the uterine artery at the junction of the base of the (peritoneal) broad ligament and the superior part of the (fascial) transverse cervical ligament. The uterovaginal nerve plexus is one of the pelvic plexuses that extend to the pelvic viscera from the inferior hypogastric plexus. Sympathetic, parasympathetic, and visceral afferent fibers pass through this plexus. Visceral afferent fibers conducting pain impulses from the intraperitoneal uterine fundus and body (superior to the pelvic pain line) follow the sympathetic innervation retrograde to reach cell bodies in the inferior thoracic–superior lumbar spinal ganglia Pain impulses from the uterine body and the vagina below the pelvic pain line follow parasympathetic fibers retrograde through the uterovaginal and inferior hypogastric plexuses and the pelvic splanchnic nerves to cell bodies in the S2 to S4 spinal sensory ganglia Visceral pain fibers, do have clinical significance because of childbirth -- all other visceral afferent fibers from the vagina that do not concern pain follow the parasympathetic route During childbirth, damage to the pelvic floor can cause loss of bladder support, leading to more mobility of the pelvic organs. This can result in a urethrocele, which is basically a change in the angle of the urethra. A rectocele, in which the rectum protrudes into the vaginal lumen. A cystocele, where you see the bladder protruding through the vaginal wall. An enterocele, which is when the upper posterior vaginal wall prolapses from the rectovaginal pouch where intestines have pushed through You can also get a uterovaginal prolapse, which is where the uterus itself starts to collapse The pelvic organ prolapse quantification system (POP-Q) is a systematic method for quantifying and describing the different prolapses -- it relies on specific measurements of nine defined points with the point of reference being the hymen or the ring POPQ: 1st degree: prolapse of the organ halfway to the hymen 2nd degree: prolapse of the organ to the hymen 3rd degree: prolapse of the organ past the hymen 4th degree: maximum descent of the organ Obstetrical trauma, during long or difficult labor, can cause weakness, necrosis, or tears in the vagina wall and sometimes beyond IBD, surgical complications, diverticulitis can also impact the vagina Injuries to the vagina lead to abnormal pathways or fistulas. There can be a fistula between the bladder and the uterus, you can have urine enter the vagina vesicovaginal or you can get uretovaginal, which is from the ureter to the vagina. Urethrovaginal fistulas as well. You can get rectovaginal fistulas as well with fecal matter coming in The rectum can prolapse, usually due to repeated trauma, but can also happen in starvation, in which the fat bodies of the ischioanal fossa disappear -- they are one of the last fat pads to go so that is seen in severe malnutrition General anesthesia: used for emergency procedures Renders the mother unconscious Clinicians monitor the maternal and fetal values Childbirth occurs passively Regional anesthesia/analgesia: Types: epidural, spinal, pudendal block Numbs specific body areas Allows the mother to be conscious and assist in labor Epidural block: one of the most popular forms of anesthesia for childbirth popular for participatory childbirth Administered at the L3-L4 level Anesthetizes birth canal, pelvic floor and the perineum without affecting the lower limbs Mother aware of contractions Spinal anesthesia: you can get a spinal headache from this Administered into the spinal subarachnoid space at L3-L4 Complete anesthesia below the waist Temporary block of motor and sensory functions Used for limited duration procedures ◦ you cannot push as much since it is mostly blocked -- but it is usually short term Pudendal nerve block: Provides local anesthesia over S2-S4 dermatomes Numbs perineum and lower vagina Does not affect uterine contractions ◦ This process is disruptive and can involve instruments being close to the infants head to get to the pudendal nerve Look at the big ones and where they are going!!! The superior bladder drains to the external iliac lymph node The testicle and the and the ovary go the lumbar region The lower part of the bladder goes to the internal iliac There is a weird divide at the end of the rectum on the anal wall that divides the mucosal lining The tip of the fundus of the uterus goes to the superficial inguinal lymph nodes The perineum is the shallow compartment of the body bounded by the pelvic outlet and separated from the pelvic cavity by fascia covering the inferior pelvic diaphragm, formed by the levator ani and coccygeus The perineal fasciae are subcutaneous tissue that has a fatty later and a deep membranous layer (Colles Fascia, or superficial perineal fascia) and the deep perineal fascia The osteofibrous structures that mark the boundaries of the perineum are going to be the: pubic symphysis, anteriorly ischiopubic rami (combined inferior pubic rami and ischial rami), anterolaterally ischial tuberosities, laterally sacrotuberous ligaments, posterolaterally inferiormost sacrum and coccyx, posteriorly A transverse line joining the anterior ends of the ischial tuberosities divides the diamond-shaped perineum into two triangles, the oblique planes of which intersect at the transverse line (Fig. 6.51A– C). The anal triangle lies posterior to this line. The anal canal and its orifice, the anus, constitute the major deep and superficial features of the triangle, lying centrally surrounded by ischio-anal fat. The urogenital (UG) triangle is anterior to this line. In contrast to the open anal triangle, the UG triangle is “closed” by a thin sheet of tough, deep fascia, the perineal membrane, which stretches between the two sides of the pubic arch, covering the anterior part of the pelvic outlet The perineal membrane thus fills the anterior gap in the pelvic diaphragm (the urogenital hiatus; Fig. 6.52A) but is perforated by the urethra in both sexes and by the vagina of the female The membrane and the ischiopubic rami to which it attaches provide a foundation for the erectile bodies of the external genitalia—the penis and scrotum of males and the pudendum or vulva of females—which are the superficial features of the triangle The midpoint of this line is the central line of the perineum known as the perineal body or the central tendon on the perineum The perineal body is the site of convergence and interlacing of fibers of several muscles, including the following: Bulbospongiosus External anal sphincter Superficial and deep transverse perineal muscles Smooth and voluntary slips of muscle from the external urethral sphincter, levator ani, and muscular coats of the rectum The fatty layer of the subcutaneous tissue also pads the external female genitalia and the perineal fascia is continuous with the Dartos fascia of the penis and scrotum The deep perineal fascia is also known as the investing or Gallaudet fascia closely surrounds the ischiocavernosus, bulbospongiosus, and superficial transverse perineal muscles and it attaches laterally to the ischiopubic rami Anteriorly, the deep perineal fascia blends with the suspensory ligament in males and with the suspensory ligament of the clitoris in females -- it is then continuous with the deep fascia covering the external oblique muscle of the abdomen and the rectus sheath The superficial perineal pouch is a potential space between the perineal fascia and the perineal membrane, bounded laterally by the ischiopubic rami In males, the superficial perineal pouch contains the: root (bulb and crura) of the penis and associated muscles (ischiocavernosus and bulbospongiosus) proximal (bulbous) part of the spongy urethra superficial transverse perineal muscles deep perineal branches of the internal pudendal vessels and pudendal nerves In females, the superficial perineal pouch contains the: clitoris and associated muscle (ischiocavernosus) bulbs of the vestibule and surrounding muscle (bulbospongiosus) greater vestibular glands superficial transverse perineal muscles related vessels and nerves (deep perineal branches of the internal pudendal vessels and pudendal nerves) The deep perineal pouch is bounded inferiorly by the perineal membrane, superiorly by the inferior fascia of the pelvic diaphragm, and laterally by the inferior portion of the obturator fascia (covering the obturator internus muscle) In both sexes, the deep perineal pouch contains part of the urethra, centrally the inferior part of the external urethral sphincter muscle, above the center of the perineal membrane, surrounding the urethra anterior extensions of the ischio-anal fat bodies In males, the deep perineal pouch contains the intermediate part of the urethra, the narrowest part of the male urethra deep transverse perineal muscles, immediately superior to the perineal membrane (on its superior surface), running transversely along its posterior aspect bulbo-urethral glands, embedded within the deep perineal musculature dorsal neurovascular structures of the penis In females, the deep perineal pouch contains the proximal part of the urethra a mass of smooth muscle in the place of deep transverse perineal muscles on the posterior edge of the perineal membrane, associated with the perineal body dorsal neurovasculature of the clitoris The pudendal canal is a passageway in the obturator that contains the pudendal artery, vein and nerve and the nerve to the obturator internus that enter at the lesser sciatic notch inferior to the ischial spine It then gives rise to the rectal artery and rectal nerve upon entering And it gives rise to the perineal nerve and the artery towards the end of the canal The scrotal nerves are called the labial nerves in females The dorsal nerve of the penis or clitoris, is a primary sensory nerve serving the male or female organ specifically the sensitive glans of the distal ends Know these arteries and their paths!!!! The anal canal is the final part of the large intestine and the GI tract From the superior aspect of the pelvic diaphragm to the anus is 2.5-3.5 cm long Your internal anal sphincter is an involuntary sphincter surrounding the superior two thirds of the anal canal and is formed by a thickening of the circular muscle layer contraction is maintained by sympathetic fibers from the superior rectal and hypogastric plexuses Relaxation or inhibition is triggered by parasympathetic fibers via the pelvic splanchnic nerves ◦ intrinsically related to peristalsis or extrinsically It temporarily relaxes in response to rectal distention by feces or gas Voluntary contraction of the puborectalis muscle and external anal sphincter is required to prevent defacation or flatulence The ampulla relaxes after initial distention and tonus returns until the next peristalsis or significant distension The external anal sphincter is a large voluntary sphincter forming a broad band around the inferior two thirds of the anal canal attached anteriorly to the perineal body and posteriorly to the coccyx via the anococcygeal ligament It blends with the puborectalis muscle superiorly Consists of subcutaneous, superficial, and deep parts; these are zones rather than muscle bellies and are often indistinct The external anal sphincter is supplied mainly by S4 through the inferior rectal nerve (Fig. 6.57), although its deep part also receives fibers from the nerve to the levator ani, in common with the puborectalis, with which it contracts in unison to maintain continence when the internal sphincter is relaxed (except during defecation). The anorectal junction, indicated by the superior ends of the anal columns, is where the rectum joins the anal canal. This is where the terminal branches of the superior rectal artery and vein are At this point, the wide rectal ampulla abruptly narrows as it traverses the pelvic diaphragm. The inferior ends of the anal columns are joined by anal valves. Superior to the valves are small recesses called anal sinuses. When compressed by feces, the anal sinuses exude mucus, which aids in evacuation of feces from the anal canal. The inferior comb-shaped limit of the anal valves forms an irregular line, the pectinate line (dentate line) (Fig. 6.59), that indicates the junction of the superior part of the anal canal (visceral; derived from the embryonic hindgut) and the inferior part (somatic; derived from the embryonic proctodeum). The pectinate line is where you will see a color difference in the mucosa above and below The pectinate line indicates the junction of the superior part of the anal canal The anal canal superior to the pectinate line differs from the inferior part in its histology, arterial supply, innervation and its venous and lymphatic drainage Arterial supply: Superior to the pectinate line: Superior Rectal artery Inferior to the pectinate line: Inferior rectal artery Middle rectal anastomoses with the other two Venous drainage: internal rectal venous plexus in both directions around the pectinate line ◦ drains to the superior rectal vein above the pectinate line ◦ drains to the inferior rectal vein below the pectinate line Lymphatic drainage: Superior to the pectinate line: internal iliac lymph nodes Inferior to the pectinate line: superficial inguinal lymph nodes Innervation: Superior to the pectinate line: visceral from the inferior hypogastric plexus Inferior to the pectinate line: somatic from the inferior anal (rectal) nerves off the pudendal nerve The inferior is sensitive to pain, touch and temperature ◦ the rest not so much, but you can still get some sensory because of stretching into other surrounding muscles An episiotomy is an incision of the perineum and inferoposterior vaginal wall to enlarge the vaginal opening, decrease traumatic tearing of the perineum and prevent uncontrolled, jagged tears of the perineal muscles Current practice in the US are less common and procedures are reserved for specific situations when there is arrested or protracted descent of the fetus, when instruments like obstetrical forceps are needed and when there is fetal distress A median episiotomy is when you make an incision of the perineal body, this is done so the resulting scar is similar to the surrounding tissue with potential to be self-limiting The risks of a median episiotomy are sphincter damage and anovaginal fistulae Associated complications are severe lacerations, long-term incontinence, pelvic prolapse and anovaginal fistulae There are also mediolateral episiotomies that appear to result in a lower incidence of severe laceration, they are less likely to be associated with damage to the anal sphincters and canal because the incision is a median incision that then turns laterally as it proceeds posteriorly that circumvents the perineal body and prevents further tearing of the anus  fractures of the pelvic girdle and specifically those involving separation of the the pubic symphysis and the puboprostatic ligaments often lead to rupture of the intermediate portion of the urethra This injury will cause urine and blood to escape into the deep perineal pouch and can move superiorly through the urogenital hiatus and spread extraperineally around the prostate and bladder A common site of rupture for the spongy urethra and urine extraversation is the bulb of the penis which typically results from a forceful blow to the perineum, such as like a straddle injury from falling onto a beam and can occur from the incorrect passage of a transurethral catheter that fails to navigate the urethral angle When the corpus spongeousum and spongy urethra rupture, urine extravasates into the superficial perineal space The direction of urine flow is determined by the attachments of the perineal fascia and urine can spread into the loose connective tissue of the scrotum, around the penis, and superiorly beneath the membranous layer of subcutaneous connective tissue of the inferior anterior abdominal wall The urine cannot travel far into the thighs because the membranous layer of superficial perineal fascia blends with the fascia latte which envelops the thigh muscle just below the inguinal ligaments Urine cannot move posteriorly into the anal triangle due to the continuity of the superficial and deep layers of perineal fascia around the superificial perineal muscles and the posterior edge of the perineal membrane Rupture of a blood vessel in the superficial perineal pouch due to trauma would result in the blood being contained in the pouch following the same pattern as the urine The male urethra is divided into four parts: intramural (preprostatic), prostatic, intermediate, and spongy The intermediate (membranous) part of the urethra begins at the apex of the prostate and traverses the deep perineal pouch, surrounded by the external urethral sphincter. It then penetrates the perineal membrane, ending as the urethra enters the bulb of the penis PL to the end of the intermediate part of the urethra is the bulbourethral glands, which ducts open into the spongy urethra The spongy (penile) urethra begins at the distal end of the intermediate part of the urethra and ends at the male external urethral orifice, which is slightly narrower than any of the other parts of the urethra. The narrowest part of the male urethra is the male external urethral orifice!!! The distal urethra gets blood from the dorsal artery of the penis and lymphatics drain into the internal iliac nodes from the intermediate urethra and the deep inguinal nodes from the spongy urethra Innervation of the male urethra for the intermediate part you get autonomic innervation via the prostatic nerve plexus which OG from the inferior hypogastric plexus and sympathetic innervation from the lumbar spinal nerves and parasympathetic innervation from the sacral levels via the pelvic splanchnic nerves and visceral afferent fibers that follow the parasympathetic fibers retrograde to the sacral spine through the spinal sensory ganglia The spongy urethra gets somatic innervation provided by the dorsal nerve of the penis which is a branch of the pudendal nerve. This innervation framework helps to regulate urethral function and sensation, contributing to both urinary and reproductive processes The scrotum is the cutaneous fibromuscular sac that has the line down the middle called the scrotal raphe, which is continuous with the penile raphe and the perineal raphe There are two compartments, one for each testicle and separated by the septum of the scrotum, a continuation of the dartos fascia The arteries that supply the scrotum are: terminal branches from the external pudendal arteries to the anterior Terminal branches of the superficial branches of the internal pudendal arteries to the posterior Lymphatics to the scrotum are: Superficial inguinal lymph nodes Innervation to the scrotum is: Anterior: anterior scrotal nerves from the ilio-inguinal nerve and the genital branch of the genitofemoral nerve Posterior: branches of the superficial perineal branches of the pudendal nerve and the perineal branch of the posterior cutaneous nerve of the thigh The penis consists of three cylindrical cavernous bodies of erectile tissue: 2 corpora cavernosa 1 corpus spongiousum The anatomical position the penis is considered erect with the dorsum directed anteriorly when flaccid Each cavernous body of the penis has a fibrous outer covering known as the tunica albuginia Superficial to the tunica is the deep fascia of the penis, also known as the buck fascia, which is a continuation of the deep perineal fascia strong membranous covering for the corpora cavernosa and corpus spongiosum, binding them together The corpus spongiosum contains the spongy urethra. The corpora cavernosa are fused with each other in the median plane, except posteriorly where they separate to form the crura of the penis (Figs. 6.60 and 6.62B). Internally, the cavernous tissue of the corpora is separated (usually incompletely) by the septum penis (which is typically incomplete) these anatomical features provide the structural basis for the penile function and they are important in understanding normal physio and potential pathologic complications The root of the penis, the attached part, consists of the crura, bulb, and ischiocavernosus and bulbospongiosus muscles he root is located in the superficial perineal pouch, between the perineal membrane superiorly and the deep perineal fascia inferiorly (see Fig. 6.53B, D). The crura and bulb of the penis consist of erectile tissue. Each crus is attached to the inferior part of the internal surface of the corresponding ischial ramus (see Fig. 6.52D), anterior to the ischial tuberosity The bulb is enlarged posteriorly and penetrated by the urethra from its intermediate part The body of the penis is the free pendulous part that is suspended from the pubic symphysis. Except for a few fibers of the bulbospongiosus muscle near the root of the penis and the ischiocavernosus muscle that embrace the crura, the body of the penis has no muscles The penis consists of thin skin, connective tissue, blood and lymphatic vessels, fascia, the corpora cavernosa, and corpus spongiosum containing the spongy urethra The glans penis is the distal expansion of the corpus spongiousum and it also forms the conical glands of the penis or the head. The margins of the glans penis project beyond the corpus cavernosus, forming the corona of the glans (gives it the extended range of the head) The spongy urethra opens at the tip of the glans penis via the external urethral orifice or the meatus Hypospadias is a common congential abnormality of the penis that occurs in about 1 in 300 newborns. The most common form is glanular hypospadias, where the external urethra orifice is instead located on the ventral aspect of the glans penis. Other forms include penile hypospadias where the defect is on the body of the penis And penoscrotal or scrotal hypospadias, where the defect is in the perineum The reason that ventral hypospadias (glanular hypospadias) is important is because during anatomical position, because the back end is the dorsal end Hypospadias is believed to be associated with inadequate production of androgens by the fetal testes The suspensory ligament is a condensation of deep fascia arising from the anterior pubic symphysis forms a sling that attaches to the deep fascia of the penis at the junction of its root and body The arterial supply of the penis: Dorsal arteries: ◦ run on each side of the deep dorsal vein in the dorsal groove between the corpora cavernosa to supply the fibrous tissue around the corpora cavernosa, the corpus spongiosum, the spongy urethra and the penile skin Deep arteries: ◦ Run distally near the center of the corpora cavernosa supplying the erectile tissue Bulb of the penis: ◦ supply the posterior corpus spongiosum and the urethra, as well as the bulbo-urethral gland Venous drainage: Deep dorsal vein of the penis drains the cavernous spaces Blood from the skin and subcutaneous tissue drain into the superficial dorsal vein(s) Penis: Innervation: ◦ S2-S4 spinal cord segments ◦ Sensory and sympathetic innervation by the dorsal nerve of the penis, a branch of the pudendal nerve ◦ Skin and root are supplied by the ilio-inguinal nerve Lymph from the skin of all the perineum in men drains to the superficial inguinal nodes ◦ the testes drain to the lumbar and pre-aortic lymph nodes Inability to obtain an erection may result from several causes... it could be a lesion of the prostatic plexus or cavernous nerves that result in the inability to achieve an erection A surgically implanted semi-rigid or inflatable penis prosthesis may assume the role of the erectile bodies Erectile function (ED) may occur in the absence of a nerve insult if you have something like CNS issues, Endocrine issues, Pituitary or Testicular disorders that can result in reduced Testosterone. Nerve fibers that are failing to stimulate erectile tissue. Blood supply is lacking. IN many cases, erection can be achieved with the assistance of oral medications or injections that increase blood flow directly to that area that cause relaxation of smooth muscle Male Perineal Muscles: Bulbospongiosus muscles: ◦ compress the bulb of the penis and corpus spongiosum ◦ Empty spongy urethra of residual urine and semen ◦ Assist erection by compressing the deep dorsal vein Ischiocavernosus muscles: ◦ Surround the crura of the penis ◦ Force blood into the corpora cavernosa ◦ Restrict the venous outflow to maintain erection erection: Erotic stimulation closes arteriovenous anastamoses PS stimulation (S2-S4) via the cavernous nerves Relaxation of smooth muscle in fibrous trabeculae and helicine arteries Blood flows into the cavernous spaces, causing engorgement and rigidity Compression of veins by bulbospongiosus and ischiocavernosus muscles Emission: Delivery of semen (sperm and glandular secretions) to prostatic urethra peristalsis of ductus deferens and seminal glands Addition of prostatic fluid (added to seminal fluid) Sympathetic response (L1-L2 nerves) Ejaculation: Closure of internal urethral sphincter (sympathetic, L1-L2) at the neck of the bladder (to prevent backflow) Contraction of urethral muscle (parasympathetic, S2-S4) and contraction of bulbospongiosus muscle (pudendal nerves, S2-S4) Remission: Sympathetic stimulation causes constriction of smooth muscles and helicine arteries Relaxation of bulbospongiosis and ischiocavernosus muscles Blood drainage from cavernous spaces into deep dorsal vein Female External Genitalia: The synonymous terms vulva and pudenda include the mons pubis, labia majora, labia minora, clitoris, bulbs of the vestible and greater and lesser vestibular glands The synonymous terms vulva and pudendum include all these parts; the term pudendum is commonly used clinically. The vulva serves as sensory and erectile tissue for sexual arousal and intercourse to direct the flow of urine to prevent entry of foreign material into the urogenital tract The mons pubis is the rounded, fatty eminence anterior to the pubic symphysis, pubic tubercles, and superior pubic rami. The eminence is formed by a mass of fatty subcutaneous tissue. The amount of fat increases at puberty and decreases after menopause. The surface of the mons is continuous with the anterior abdominal wall. After puberty, the mons pubis is covered with coarse pubic hairs. The labia majora are prominent folds of skin that indirectly protect the clitoris and urethral and vaginal orifices (Fig. 6.67). Each labium majus is largely filled with a finger-like “digital process” of loose subcutaneous tissue containing smooth muscle and the termination of the round ligament of the uterus (Fig. 6.68). The labium majus passes inferoposteriorly from the mons pubis toward the anus creating the pudendal cleft which houses the labia minora and the vestibule he external aspects of the labia majora of the adult are covered with pigmented skin containing many sebaceous glands and are covered with crisp pubic hairs. The internal aspects of the labia are smooth, pink, and hairless. The labia majora are thicker anteriorly where they join to form the anterior commissure. Posteriorly, in nulliparous women (those never having borne children), they merge to form a ridge, the posterior commissure, which overlies the perineal body and is the posterior limit of the vulva. This commissure usually disappears after the first vaginal birth. The labia minora are rounded folds of fat-free, hairless skin. They are enclosed in the pudendal cleft and immediately surround and close over the vestibule of vagina into which both the external urethral and vaginal orifices open. They have a core of spongy connective tissue containing erectile tissue at their base and many small blood vessels Anteriorly, the labia minora form two laminae. The medial laminae of each side unite as the frenulum of the clitoris. The lateral laminae unite anterior to (or often anterior and inferior to, thus overlapping and obscuring) the glans clitoris, forming the prepuce (foreskin) of the clitoris In young women, especially virgins, the labia minora are connected posteriorly by a small transverse fold, the frenulum of the labia minora (fourchette). Although the internal surface of each labium minus consists of thin moist skin, it has the pink color typical of mucous membrane and contains many sebaceous glands and sensory nerve endings The clitoris is an erectile organ located where the labia minora meet anteriorly (Figs. 6.67, 6.68, and 6.69A). The clitoris consists of a root, a small, cylindrical body, and the glans clitoris, the tip of the body he root is composed of the two tapered and separated proximal portions or crura of the erectile bodies, the corpora cavernosa. The crura firmly attach to the inferior pubic rami and perineal membrane and are covered inferiorly by muscle (ischiocavernosus) deep to the labia The angle and the proximal body are attached to the pubic symphysis by a suspensory ligament. The union of the crura is also joined by anterior extensions of the bulbs of the vestibule, collectively forming a bulboclitoral erectile organ [Di Marino & Lepidi, 2014] (Fig. 6.69B). Within the body, the corpora are ovoid in cross-section with their apposed surfaces forming a central septum (Fig. 6.69C). They are bound by surrounding clitoral fascia. The distal body and glans are commonly covered by a loose fold of skin, the prepuce, or hood of the clitoris In contrast to the penis, the clitoris is not functionally related to the urethra or to urination. It functions solely as an organ of sexual arousal. The clitoris is highly sensitive and enlarges on tactile stimulation. The glans clitoris is the most highly innervated part of the clitoris and is densely supplied with sensory endings. The vestibule of the vagina is the space surrounded by the labia minora into which the orifices of the urethra and vagina and the ducts of the greater and lesser vestibular glands The external urethral orifice is located 2–3 cm postero-inferior to the glans clitoris and anterior to the vaginal orifice. On each side of the external urethral orifice are the openings of the ducts of the para- urethral glands. Openings of the ducts of the greater vestibular glands are located on the upper, medial aspects of the labia minora, in 5 and 7 o’clock positions relative to the vaginal orifice in the lithotomy position. The bulbs of the vestibule are paired masses of elongated erectile tissue, approximately 3 cm in length (Fig. 6.68). The bulbs lie along the sides of the vaginal orifice, superior or deep to (not within) the labia minora, immediately inferior to the perineal membrane (see Fig. 6.52D, E). They are covered inferiorly and laterally by the bulbospongiosus muscles extending along their length. The bulbs of the vestibule are homologous with the bulb of the penis. The greater vestibular glands (Bartholin glands), approximately 0.5 cm in diameter, are located in the superficial perineal pouch - secreting mucus during sexual arousal The lesser vestibular glands are small glands on each side of the vestibule of the vagina that open into it between the urethral and vaginal orifices. These glands secrete mucus into the vestibule, which moistens the labia and vestibule. These glands are normally not palpable but can become infected in something called bartholenitis Bartholin gland cysts can swell without infection and mucin accumulates Bartholin gland absesses or infections are super tender and are managed by antibiotics Arterial supply to the vulva: External and internal pudendal arteries: ◦ mostly internal ◦ The labial arteries and clitoral arteries are branches off the internal pudendal Venous drainage of the vulva: Internal pudendal vein tributaries Erectile sinus engorgement during excitement of the sexual response causes increased clitoral and bulb size consistency Innervation: mons pubis and anterior labia are innervated by the anterior labial nerves, derived from the ilio- inguinal nerve and the genital branch of the genitofemoral nerve The posterior aspect is supplied by the perineal branch of the posterior cutaneous nerve of the thigh laterally and the pudendal nerve centrally Lymphatic drainage of the female perineum: Lymphatic drainage from the skin of the perineum and the anoderm inferior to the pectinate line of the anorectum and the inferiomost vagina, vaginal orifice and vestibule drain into the superficial inguinal nodes Lymphatic drainage from the clitoris, vestibular bulb, and anterior labia drain to the deep inguinal nodes Lymphatic drainage from the urethra drains to the internal iliac or sacral nodes In Class Monday - 07/01/2024 Pelvis and Head Structures Female Pelvis: First organ after the pubic symphysis is the bladder Urethra is ensheathed in external urethral sphincter Vagina is posterior the the urethra and runs up to the Uterus Female perineum: lots of muscles for specific functions Vaginal opening ◦ labia majora ◦ labia minora ◦ medial to these is the clitoris ◦ Deep layer: ‣ bulbospongiousus - clitoral erection -- men penile erection innervated by perineal nerves ‣ Urethral muscle? ‣ Levator Ani Muscle nerve to levator ani -- all of them Puborectalis - up front and centered and ensheaths the rectum Pubococcygeus Iliococcygeus ‣ Ischiocavernosus muscles innervated by perineal nerve assist bulbospongiousus muscle in maintaining erection ‣ Bartholin glands - secrete fluid that helps lubricate the vagina can get bartholin cysts which just require antibiotics Case #1: Pelvic Organ Prolapse!! Case #2: Ureteral injury secondary to recent surgery Case #3: Pelvic exam: ◦ signs of infection ◦ signs of trauma ◦