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HAYAT MEDICAL COLLEGE PELVIS AND PERINEIUM By Solomon Seyoum (MSC in Anatomy, MPH) October, 2024 G.c. 1  The pelvic region Introduction  Is the part of the trunk inferoposterior to the abd...

HAYAT MEDICAL COLLEGE PELVIS AND PERINEIUM By Solomon Seyoum (MSC in Anatomy, MPH) October, 2024 G.c. 1  The pelvic region Introduction  Is the part of the trunk inferoposterior to the abdomen.  Is the area of transition between the trunk and the lower limbs.  Is also the space or compartment surrounded by the pelvic girdle.  Externally, the pelvis is covered or overlapped by:  The inferior anterolateral abdominal wall anteriorly.  The gluteal region of the lower limb posterolaterally.  The perineum inferiorly. The pelvic cavity  Is enclosed by the true pelvis.  Consists of the pelvic inlet, walls, and floor. 2  Is continuous superiorly with the abdominal cavity.  Bone of pelvis  The bony pelvis’s functions are:  Transmit the weight of the body from the vertebral column to the femurs.  It contains, supports, and protects the pelvic viscera  Provides attachment for trunk and lower limb muscles.  The bony pelvis is composed of four bones:  the two hip bones, which form the lateral and anterior walls  the sacrum and the coccyx, which are part of the vertebral column and form the back wall. Pelvic girdle  Is a basin-shaped ring of bones that connects the vertebral column to the two femurs.  Is formed by three bones in the mature individual:  Right and left hip bones 3  Fig. Lateral view of hip bone Hip Bone  Formed by the fusion of ilium, ischium, and pubis at the end of teenage years.  At birth- the three primary bones are joined by hyaline cartilage.  At puberty- the 3 bones are separated by a Y-shaped triradiate cartilage.  The bones begin to fuse between 15 and 17 years of age.  fusion is complete between 4  The pelvis  It is divided into greater (false) and lesser (true) pelvis by the pelvic inlet. Pelvic inlet (superior pelvic aperature)  The bony edge (rim) surrounding and defining the pelvic inlet is the pelvic brim.  It is the circular opening between the abdominal cavity and the pelvic cavity through which structures traverse between the abdomen and pelvic cavity.  It is completely surrounded by bones and joints.  It is bounded  Posteriorly by the sacral promontory.  Laterally by the iliopectineal lines  Anteriorly by the symphysis pubis. Function 5  Help structures to pass b/n the abdomen and pelvic cavity.  Pelvic outlet (inferior pelvic aperture)  It is bounded by the:  Pubic arch anteriorly.  Ischial tuberosities laterally.  Inferior margin of the sacrotuberous ligament posterolaterally.  Tip of the coccyx posteriorly. Figure - Pelvic outlet. 6  The greater (false) pelvis  It is surrounded by the superior pelvic girdle.  It is the part of the pelvis:  Superior to the pelvic inlet.  Bounded by the iliac alae posterolaterally and the anterosuperior aspect of the S1 vertebra posteriorly.  Occupied by abdominal viscera (e.g., the ileum and sigmoid colon). The lesser (true) pelvis  It is the part of the pelvis:  Between the pelvic inlet and the pelvic outlet.  Is surrounded by the inferior pelvic girdle.  Bounded by the pelvic surfaces of the hip bones, sacrum, and coccyx. 7  The lesser pelvis  Includes the true pelvic cavity and the deep parts of the perineum, specifically the ischioanal fossae. 8 Fig. Comparison of male and female bony pelvis 9 Fig. Comparison of male and female pelvis 10  Classification of pelvis  Pelvis was classified into four groups: 1- The gynecoid type  Present in about 41% of women.  Is the typical female pelvis. 2- The android type  Present in about 33% of white females and 16% of black females.  Is the male or funnel-shaped pelvis with a contracted outlet. 3- The anthropoid type  Present in about 24% of white females and 41% of black females.  Is long, narrow, and oval shaped. 4- The platypelloid type  Present in only about 2% of women 11  Fig. Types of pelvis Note  Android and anthropid type are common in male  Android and gynecoid type are common in white female  Gynecoid and anthropoid type are common in black female  Platepelloid is uncommon in 12  Joints and Ligaments of Pelvic Girdle 1- SACROILIAC JOINTS  Are synovial joints b/n  The L-shaped articular facets on the lateral surfaces of the sacrum  Similar facets on the iliac parts of the pelvic bones.  Is stabilized by three ligaments: 1- The anterior sacro-iliac ligament. 2- The interosseous sacro-iliac ligament. 3- The posterior sacro-iliac ligament. 13 Fig. Sacroiliac joint  2- PUBIC SYMPHYSIS  It is a joint b/n adjacent surfaces of the pubic bones.  Its Two major ligaments :  Superior pubic ligament  Inferior pubic ligament. 14  3- LUMBOSACRAL JOINTS  The lumbosacral joints are formed between vertebra LV and the sacrum and consist of: 1-Two zygapophysial (facet joints) joint  It Is b/n adjacent inferior and superior articular processes L5 and S1. 2- An intervertebral joint  it is formed b/n the bodies of vertebrae LV and SI disc. Ligament  Iliolumbar ligaments  lumbosacral ligaments 15  4- Sacrococcygeal joint  It is a Joint b/n the apex of the sacrum and the base of the coccyx. Ligament  Anterior sacrococcygeal ligaments  Posterior sacrococcygeal ligaments. 16  Clinical anatomy Pelvic Diameters (Conjugates)  To determine capacity of female pelvis for childbearing, diameters of lesser pelvis are noted radiographically or manually during a pelvic examination (PE).  The true (obstetrical) conjugate  The minimum anteroposterior (AP) diameter of the lesser pelvis  It is from the middle of sacral promontory to posterosuperior margin of SP.  It is the narrowest fixed distance through which baby's head must pass in a vaginal delivery.  It cannot be measured directly during a (PE) b/se of presence of the bladder. 17  Clinical anatomy The diagonal conjugate  It can be measured directly during a PE and help to estimate true conjugate.  It is measured by palpating sacral promontory with tip of middle finger, using other hand to mark level of inferior margin of the SP on the examining hand.  After the examining hand is withdrawn, the distance b/n the tip of the index finger and the marked level of the SP is measured to estimate the true conjugate, which should be 11.0 cm or greater. 18  Clinical anatomy The interspinous distance  It is the narrowest part of the pelvic canal through which a baby's head must pass at birth but it is not a fixed distance. During a pelvic examination  if the ischial tuberosities are far enough apart to permit three fingers to enter the vagina side by side,  the subpubic angle is considered sufficiently wide to permit passage of an average fetal head at full term. 19  Pelvic Fractures  Weak areas of the pelvis, where fractures often occur, are the:  pubic rami,  acetabula,  region of the SIJ  alae of the ilium.  Pelvic fractures may cause injury to  pelvic soft tissues, 20  PELVIC CAVITY  It is the funnel-shaped.  It is the inferoposterior part of the abdominopelvic cavity.  It is continuous with the abdominal cavity at the pelvic inlet.  It Contains:  the terminal parts of the ureters, the urinary bladder, rectum, pelvic genital organs, blood vessels, lymphatics, and nerves.  it also contains loops of small intestine (mainly ileum) and large intestine (appendix and transverse and/or sigmoid colon).  It is limited inferiorly by the musculofascial pelvic diaphragm.  It is bounded posteriorly by the coccyx and inferiormost sacrum  The bodies of the pubic bones, and the pubic symphysis form 21 an anteroinferior wall FIGURE. Thoracic and abdominopelvic cavities. 22  PELVIC CAVITY Walls and Floor of Pelvic Cavity The pelvic cavity has:  an anteroinferior wall  two lateral walls  a posterior wall.  pelvic floor The anteroinferior pelvic wall:  Is formed primarily by the bodies and rami of pubic bones and pubic symphysis.  It Participates in bearing the weight of the urinary bladder. The lateral pelvic walls:  Are formed by the right and left hip bones  Covered by the fleshy attachments of the obturator internus muscles 23  PELVIC CAVITY POSTERIOR WALL (POSTEROLATERAL WALL AND ROOF)  In the anatomical position, the posterior pelvic wall consists of  a bony wall and roof in the midline (formed by the sacrum and coccyx)  musculoligamentous posterolateral walls, formed by the ligaments associated with the sacroiliac joints and piriformis muscles. ligaments include the anterior sacroiliac, sacrospinous, and sacrotuberous ligaments. 24  PELVIC CAVITY Pelvic floor  Is formed by the funnel-shaped pelvic diaphragm, which consists of:  The levator ani and coccygeus muscles  Fascias covering the superior and inferior aspects of these muscles.  The pelvic diaphragm stretches between the anterior, the lateral, and the posterior walls of the lesser pelvis.  An anterior gap between the medial borders of the levator ani muscles of each side (urogenital hiatus) gives passage to the urethra and, in females, the vagina 25  Muscles of pelvic walls and floor Lateral wall contain Obturator internus  Proximal Attachment=Pelvic surfaces of ilium and ischium; obturator membrane  Distal Attachment=Greater trochanter of femur  Innervation = Nerve to obturator internus (L5, S1, S2)  Main Action = Rotates thigh laterally; assists in holding head of femur in acetabulum. 26  Muscles of pelvic walls and floor Posterolateral wall contain Piriformis  Proximal Attachment  Pelvic surface of S2-S4 segments; superior margin of greater sciatic notch and sacrotuberous ligament  Distal Attachment=Greater trochanter of femur  Innervation – Anterior rami of S1 and S2  Main Action - Rotates thigh laterally; abducts thigh; assists in holding head of femur in acetabulum 27  Muscles of pelvic walls and floor Floor contains pelvic diaphragm composed of : 1. Coccygeus (ischiococcygeus)  Proximal Attachment=Ischial spine  Distal Attachment= Inferior end of sacrum and coccyx  Innervation – Branches of S4 and S5 spinal nerves  Action - Forms small part of pelvic diaphragm that supports pelvic viscera; flexes coccyx. 28  Muscles of pelvic walls and floor 2. Levator ani (puborectalis, pubococcygeus, and iliococcygeus) Proximal Attachment=Body of pubis; tendinous arch of obturator fascia; ischial spine Distal Attachment=Perineal body; coccyx; anococcygeal ligament; walls of prostate or vagina, rectum, and anal canal Innervation – Nerve to levator ani (branches of S4), inferior anal (rectal) nerve, and coccygeal plexus Action - Forms most of pelvic diaphragm that helps support pelvic viscera and resists increases in intra-abdominal pressure to assist in maintaining urinary and fecal continence 29  Fig. Muscles of Floor and walls of pelvis. GURE. Puborectalis muscle. 30  Injury to Pelvic Floor  Weakening of the levator ani and pelvic fascia from stretching or tearing during childbirth.  May decrease support for the vagina, bladder, uterus, or rectum, or alter the position of the neck of the bladder and the urethra.  These changes may cause:  Urinary stress incontinence= Characterized by dribbling of urine when intra- abdomenal pressure is raised during coughing and lifting.  Lead to the prolapse of one or more pelvic organs. e.g. Cystocele. 31  NEUROVASCULAR STRUCTURES OF PELVIS Pelvic Arteries  Six main arteries enter the lesser pelvis of females:  The paired internal iliac and ovarian arteries  The unpaired median sacral and superior rectal arteries.  Four main arteries enter the lesser pelvis of males.  The paired internal iliac.  The unpaired median sacral and superior rectal arteries Internal iliac artery (IIA)  Is the principal artery of the pelvis.  Supplies most of the blood to pelvic viscera and some to musculoskeletal part of pelvis.  It also supplies branches to the gluteal region, medial thigh regions, and the perineum.  It arises from the common iliac artery at the level of the IV disc b/n the L5 and S1.  It divide into anterior and posterior divisions (trunks) at the32 superior edge of the greater sciatic foramen.  Pelvic Arteries Anterior division of Internal Iliac Artery (IIA)  The branches of the anterior division of the IIA are: 1- Umbilical Artery  Conduct deoxygenated blood to the placenta  Runs a short pelvic course, gives off superior vesical arteries, then obliterates, becoming medial umbilical ligament  Distributed to Superior aspect of urinary bladder and, in some males, ductus deferens (via superior vesical arteries and artery to ductus deferens). 2- Obturator Artery  It Runs anteroinferiorly on obturator fascia of lateral pelvic wall, exiting pelvis via obturator canal  Within the pelvis, the obturator artery gives off muscular branches, a nutrient artery to the ilium, and a pubic branch.  It supplies Pelvic muscles, nutrient artery to ilium, head of femur, and muscles of medial compartment of thigh  Form Anastomosis with Inferior epigastric (via pubic branch); umbilical 33  Pelvic Arteries 3- Inferior Vesical Artery  Occurs only in males and replaced by the vaginal artery in females.  It Passes subperitoneally in lateral ligament of bladder, giving rise to prostatic artery and occasionally the artery to the ductus deferens  It is distributed to Inferior aspect of male urinary bladder, pelvic part of ureter; prostate, and seminal glands; occasionally ductus deferens  Forms Anastomosis with Superior vesical artery. 4- Vaginal Artery  Is the homolog to the inferior vesical artery in males.  It Divides into vaginal and inferior vesical branches  Distribution:  Vaginal branch: lower vagina, vestibular bulb, and adjacent rectum;  inferior vesical branch: fundus of urinary bladder  Forms Anastomosis with Vaginal branch of uterine artery, superior vesical artery 34  Pelvic Arteries 5- Uterine Artery  It usually arising separately and directly from the internal iliac artery  It descends on the lateral wall of the pelvis, anterior to the internal iliac artery, and passes medially to reach the junction of the uterus and vagina.  As it passes medially, the uterine artery passes directly superior to the ureter.  On reaching the side of the cervix, the uterine artery divides into A- Descending vaginal branch- Supplies the cervix and vagina B- Ascending branch  Bifurcates into ovarian and tubal branches.  anastomose with the ovarian and tubal branches of the ovarian artery. 35  Pelvic Arteries 6- Middle Rectal Artery  It may arise independently from the internal iliac artery, or it may arise in common with the inferior vesical artery or the internal pudendal artery.  It Descends in pelvis to inferior part of rectum  Distribution: Inferior part of rectum, seminal glands, prostate (vagina)  Forms Anastomosis with Superior and inferior rectal arteries 7- Internal Pudendal Artery  It gives the artery that supply the perineal structure  It Exits pelvis via greater sciatic foramen, enters perineum (ischioanal fossa) via lesser sciatic foramen, passes via pudendal canal to UG triangle  Distribution: Main artery of perineum, including muscles and skin of anal and urogenital triangles, erectible bodies.  Forms Anostomosis: with (Umbilical artery; prostatic branches of inferior vesical artery in males) 36  Pelvic Arteries 8- Inferior Gluteal Artery  Is the larger terminal branch of anterior division of the IIA.  It Exits pelvis via greater sciatic foramen  It supplies the muscles and skin of the buttock and the posterior surface of the thigh.  Forms Anastomosis with Deep femoral artery (via medial and lateral circumflex femoral arteries). Posterior Division of Internal Iliac Artery. gives rise to 1- Iliolumbar artery:  Iliac branch - supplies the iliacus muscle and ilium  A lumbar branch - supplies the psoas major and quadratus lumborum muscles.  Forms anastomosis with Circumflex iliac artery and 4th (and lowest) lumbar artery 2- Lateral sacral (superior and inferior) arteries:  Its spinal branches supply the spinal meninges. 37  Some its branches supply erector spinae muscles of back and skin  Pelvic Arteries 3- Superior gluteal artery:  The largest branch of the posterior division.  Supplies the Piriformis, 3 gluteal muscles and tensor fasciae latae. OVARIAN ARTERY  It crosses pelvic brim, descends in suspensory ligament of ovary  Arises from the abdominal aorta.  It has: an ovarian branch and a tubal branch, which supply the ovary and uterine tube, respectively.  It also supply Abdominal and/or pelvic ureter  Forms anastomosis with Uterine artery via tubal and ovarian branches. MEDIAN SACRAL ARTERY  Arises from the abdominal aorta  Descends close to midline over L4 and L5 vertebrae, sacrum, and coccyx  Supply Inferior lumbar vertebrae, sacrum, and coccyx 38  Forms anastomosis with Lateral sacral artery (via medial sacral  Pelvic Arteries SUPERIOR RECTAL ARTERY  Is the direct continuation of the inferior mesenteric artery.  It Crosses left common iliac vessels and descends into pelvis between layers of sigmoid mesocolon  It Supply superior part of rectum  It forms anastomosis with Middle rectal artery; inferior rectal (internal pudendal) artery. 39  Fig- Arteries of pelvis 40  Pelvic Veins  Various plexuses within the lesser pelvis (rectal, vesical, prostatic, uterine, and vaginal) unite and are drained mainly by tributaries of the internal iliac veins. The internal iliac veins  Form superior to the greater sciatic foramen  It merge with the external iliac veins to form the common iliac veins (CIVs).  The CIVs at the level of vertebra L4 or L5 to form the IVC. The superior rectal vein  drains into the inferior mesenteric vein of the hepatic portal system. The lateral sacral veins  They anastomose with the internal vertebral venous plexus, providing an alternate collateral pathway to reach either the inferior or superior vena cava.  It may also provide a pathway for metastasis of prostatic or ovarian cancer to vertebral or cranial sites. 41  Pelvic Veins The iliolumbar veins  from the iliac fossae of the greater pelvis usually drain into the common iliac veins instead. The median sacral veins  coalesce to form a single vein that joins either the left common iliac vein or the junction of the two common iliac veins to form the inferior vena cava. The ovarian veins or testicular veins  follow the course of the corresponding arteries;  on the left, they join the left renal vein  on the right, they join the inferior vena cava in the abdomen. 42 FIGURE- Pelvic veins. 43  Lymph Nodes of Pelvis 1- External iliac lymph nodes:  Lie above the pelvic brim, along the external iliac vessels.  They receive lymph:  Mainly from the inguinal lymph nodes.  They also receive lymph from pelvic viscera  Drain into the common iliac nodes. 2- Internal iliac lymph nodes:  Clustered around the anterior and posterior divisions of the internal iliac artery and the origins of the gluteal arteries.  They receive drainage from  Inferior pelvic viscera, deep perineum, and gluteal region.  Drain into the common iliac nodes. 3- Sacral lymph nodes:  Lie in the concavity of the sacrum  They receive lymph from posteroinferior pelvic viscera  Drain either to internal or common iliac nodes. 44  Lymph Nodes of Pelvis 4- Common iliac lymph nodes:  Lie superior to the pelvis, along the common iliac blood vessels.  Receive drainage from the three main groups listed above.  These nodes begin a common route for drainage from the pelvis that passes next to the lumbar (caval/aortic) nodes. Fig. Lymph Nodes of Pelvis 45  Pelvic Nerves  The pelvis is innervated mainly by  the sacral and coccygeal spinal nerves  the pelvic part of the autonomic nervous system.  Obturator nerve  Arises from the anterior rami of spinal nerves L2-L4 in the abdomen (greater pelvis) and enters the lesser pelvis.  It Leave the pelvis through obturator canal.  Supply the medial thigh muscles.  No pelvic structures are supplied by the obturator nerve. Lumbosacral trunk  Is formed when the descending part of the L4 nerve unites with the anterior ramus of L5 nerve at or immediately superior to the pelvic brim.  The trunk passes inferiorly, on the anterior surface of 46 the ala of the sacrum, and joins the sacral plexus.  Pelvic Nerves Sacral plexus  Is located on the posterolateral wall of the lesser pelvis.  Most of its branches pass through the greater sciatic foramen.  Some of examples of nerves arising from sacral plexus:  The sciatic nerve is the largest nerve in the body. It is formed as the large anterior rami of spinal nerves L4-S3  The pudendal nerve is the main nerve of the perineum and the chief sensory nerve of the external genitalia. S2 to S4  The superior gluteal nerve from L4 to S1  The inferior gluteal nerve from L5 to S2 FIGURE Somatic nerves of pelvis—the sacral plexus. 47  Pelvic Nerves Coccygeal plexus  Is a small network of nerve fibers formed by the anterior rami of S4 and S5 and the coccygeal nerves.  It supplies part of levator ani, and the sacrococcygeal joint.  The anococcygeal nerves from S4 to Co  Arises from coccygeal plexus and pierce coccygeus and anococcygeal ligament  Supply a small area of skin b/n tip of coccyx and the anus. 48 FIG. Nerves and nerve plexuses of pelvis. 49  Pelvic autonomic nerves  Autonomic nerves enter the pelvic cavity via four routes: 1-Sacral sympathetic trunks:  Provide sympathetic innervation to the lower limbs. 2- Periarterial plexuses:  Postsynaptic, sympathetic, vasomotor fibers to superior rectal, ovarian, and internal iliac arteries and their derivative branches. 3- Hypogastric plexuses:  Most important route by which sympathetic fibers are conveyed to the pelvic viscera. 4- Pelvic splanchnic nerves:  Are pathway for parasympathetic innervation of pelvic viscera and descending and sigmoid colon. 50  The sacral sympathetic trunks  Are the inferior continuation of the lumbar sympathetic trunks.  Each of the sacral trunks usually has four sympathetic ganglia.  The sacral trunks descend on the pelvic surface of the sacrum and converge to form the small median ganglion impar (coccygeal ganglion) anterior to the coccyx.  It descend posterior to the rectum in the extraperitoneal connective tissue and send communicating branches (gray rami communicantes) to each of the anterior rami of the sacral and coccygeal nerves.  They also send small branches to the median sacral artery and the inferior hypogastric plexus.  The primary function of the sacral sympathetic trunks is  to provide postsynaptic fibers to the sacral plexus for sympathetic innervation of the lower limb. The periarterial plexuses of the ovarian, superior rectal, and internal iliac arteries  Are minor routes by which sympathetic fibers enter the pelvis. 51  The hypogastric plexuses (superior and inferior)  Are networks of sympathetic and visceral afferent nerve fibers.  The superior hypogastric plexus  Its main part is a prolongation of the intermesenteric plexus, which lies inferior to the bifurcation of the aorta.  It carries fibers conveyed to and from the intermesenteric plexus by the L3 and L4 splanchnic nerves.  It enters the pelvis, dividing into right and left hypogastric nerves, which descend on the anterior surface of the sacrum.  These nerves descend lateral to the rectum within hypogastric sheaths  It merge with the pelvic splanchnic nerves to form the right and left inferior hypogastric plexuses. 52  The hypogastric plexuses (superior and inferior)  The inferior hypogastric plexuses  contain both sympathetic and parasympathetic fibers as well as visceral afferent fibers, which continue to the pelvic viscera Here they form sub-plexuses collectively referred to as the pelvic plexuses.  In both sexes, sub-plexuses are associated with the lateral aspects of the rectum and inferolateral surfaces of the bladder.  In the male sub-plexuses are also associated with the prostate and seminal glands.  In females, sub-plexuses are also associated with the cervix of the uterus and the lateral fornices of the vagina. 53  Pelvic splanchnic nerves  Arise in the pelvis from the anterior rami of spinal nerves S2-S4 of the sacral plexus.  They convey presynaptic parasympathetic fibers derived from the S2-S4 spinal cord segments and visceral afferent fibers from cell bodies in the spinal ganglia of the corresponding spinal nerves.  The greatest contribution of these fibers is usually from the S3 nerve.  the sympathetic component  produces vasomotion  inhibits peristaltic contraction of the rectum and  The parasympathetic fibers distributed within the pelvis  stimulate contraction of the rectum and bladder for defecation and urination, respectively.  Parasympathetic fibers in the prostatic plexus penetrate the pelvic floor to reach the erectile bodies of the external genitalia, producing erection. 54 FIGURE-Autonomic nerves of pelvis. 55  PELVIC VISCERA The pelvic viscera include the 1- Distal parts of the urinary system - Pelvic part of ureter - bladder - Pelvic part of urethra 2- Reproductive system. - Female internal genital organs - Male internal genital organs 3- Digestive tract - rectum  The pelvic urinary organs 57  The pelvic urinary organs The pelvic urinary organs are the: Pelvic portions of the ureters, which carry urine from the kidneys. Urinary bladder, which temporarily stores urine. Urethra, which conducts urine from the bladder to the exterior 58  Ureters  Are muscular tubes, 25-30 cm long  Connect the kidneys to the urinary bladder.  Are retroperitoneal.  The ureter enters the lessor pelvis by crossing the bifurcation of the common iliac artery or the beginning of the EIA.  The pelvic parts of the ureters:  run on the lateral walls of the pelvis  parallel to the anterior margin of the greater sciatic notch.  B/n the parietal pelvic peritoneum and the IIAs.  Ureter curve anteromedially, superior to the levator ani, and enter the urinary bladder opposite the ischial spine. 59  Ureters  The inferior ends of the ureters are surrounded by the vesical venous plexus.  The ureters pass obliquely through the muscular wall of the urinary bladder in an inferomedial direction, entering the outer surface of the bladder ~ 5 cm apart.  Their internal openings into the lumen of the empty bladder are separated by ~ 2.5cm  The oblique passage ureters in to wall of bladder provides a valve like action, which prevents a reverse flow of urine toward the kidneys as the bladder fills.  Urine is transported down the ureters by means of peristaltic contractions  In females  the ureters passes medial to origin of uterine artery and continues to the level of the ischial spine, where it is crossed superiorly by uterine artery. 60  It then passes close to the lateral part of the fornix of the vagina  Ureters  In males  the only structure that passes between the ureter and the peritoneum is the ductus deferens. It crosses the ureter within the ureteric fold of peritoneum.  It enters the posterosuperior angle of the bladder, just superior to the seminal gland. FIGURE- Right half of the pelvis 61 showing relations of the ureter and vas deferens.  Ureters  In the pelvis, the ureter is crossed by:  the ductus deferens in men  the uterine artery in women Constrictions  The ureter possesses three constrictions:  where the renal pelvis joins the ureter in the abdomen  where it crosses the pelvic brim to enter the pelvis  where it pierces the bladder wall. 62  Clinical anatomy Ureteric Calculi 63  Ureters The arterial supply  Ureteric branches extending from the common iliac, internal iliac and ovarian arteries.  The terminal parts of the ureter  in females are supplied by branches of the uterine arteries.  in male are supplied by: the inferior vesical arteries. The venous drainage  Parallels the arterial supply, draining to veins with corresponding names. Lymphatic vessels  pass primarily to common and internal iliac nodes. 64  Ureters Innervation of Ureters.  The nerves to the ureters derive from adjacent autonomic plexuses (renal, aortic, superior and inferior hypogastric).  The ureters are primarily superior to the pelvic pain line.  Afferent (pain) fibers from the ureters follow sympathetic fibers in a retrograde direction to reach the spinal ganglia and spinal cord segments of T11-L1 or L2  Ureteric pain is usually referred to the ipsilateral lower quadrant of the abdomen, especially to the groin (inguinal region). 65 Fig. Innervation of ureters.  Urinary bladder  Is a hollow viscus with strong muscular walls.  Is characterized by its distensibility.  Is a temporary reservoir for urine.  Varies in size, shape, position, and relationships according to its content and the state of neighboring viscera.  When empty, the adult urinary bladder :  It is located in the lesser pelvis, lying partially superior to and partially posterior to the pubic bones.  It is separated from pubic bones by the potential retropubic space (of Retzius)  It lies mostly inferior to the peritoneum, resting on the  pubic bones and pubic symphysis anteriorly  prostate (males) or anterior wall of the vagina posteriorly.  The bladder is relatively free within the extraperitoneal 66  Urinary bladder  In females  The posterior aspect of the bladder rests directly upon the anterior wall of the vagina  Paracolpium is the tendinous arch of the pelvic fascia to which lateral part of vagina attaches on. It provides an indirect but important factor in supporting the urinary bladder. 67  Urinary bladder  In infants and young children  The urinary bladder is in the abdomen even when empty.  By 6 years of age  The bladder usually enters the greater pelvis  It is not located entirely within the lesser pelvis until after puberty. An empty bladder in adults  It lies almost entirely in the lesser pelvis, its superior surface level with the superior margin of the pubic symphysis. When the bladder fills  It enters the greater pelvis.  In some individuals  a full bladder may ascend to the level of the umbilicus. Fig. The bladder of an infant lies almost 68 entirely in the abdominal cavity FIGURE. Viscera in hemisected male and female pelvis. 69  Urinary bladder The bladder has four surfaces:  Superior, two inferolateral and posterior surfaces. When empty, the bladder is somewhat tetrahedral and externally has:  An apex, body, fundus, and neck. The apex of the bladder  Points toward the superior edge of the symphysis pubis when the bladder is empty.  the median umbilical ligament continues from it superiorly up the anterior abdominal wall to the umbilicus. The fundus of the bladder  Is opposite the apex, formed by the somewhat convex posterior wall. The body of the bladder  Is the major portion of the bladder b/n apex and fundus. The fundus and inferolateral surfaces 70  Urinary bladder The neck of the bladder  It surrounds the origin of the urethra at the point where the two inferolateral surfaces and the base intersect.  The neck is the most inferior part of the bladder and also the most 'fixed' part.  lies inferiorly and rests on the upper surface of the prostate.  It is held in position by ligaments that are thickenings of the pelvic fascia. These are:  Puboprostatic ligaments in the male. It is paired fibromuscular bands which blend with the fibrous capsule of the prostate, which surrounds the neck of the bladder and adjacent part of the urethra.  Pubovesical ligaments in the female. It is a pair of tough fibromuscular bands, which connect the neck and pelvic part of the urethra to the posteroinferior aspect of each pubic bone: It help support the bladder together with the perineal membrane 71  Urinary bladder  Only the superior surface is covered by peritoneum.  In males the fundus is separated from the rectum  centrally by only the fascial rectovesical septum  laterally by the seminal glands and ampullae of the ductus deferentes.  In females  the fundus is directly related to the superior anterior wall of the vagina. 72  Urinary bladder  The walls of the bladder  Are composed chiefly of the detrusor muscle.  Toward the neck of the male bladder, the muscle fibers form the involuntary internal urethral sphincter.  This sphincter contracts during ejaculation to prevent retrograde ejaculation of semen into the bladder.  In males, the muscle fibers in the neck of the bladder are continuous with the fibromuscular tissue of the prostate  In females these fibers are continuous with muscle fibers in the wall of urethra. 73  Urinary bladder The trigone of the bladder  The mucous membrane of the greater part of the empty bladder is thrown into folds that disappear when the bladder is full.  The area of m/m covering internal surface of the base of the bladder is called the trigone.  It is Formed:  superiorly by The right and left ureteric orifices  inferiorly by internal urethral orifice The ureteric orifices are encircled by loops of detrusor musculature that tighten when the bladder contracts to assist in preventing reflux of urine into the ureter.  The uvula of the bladder  It is a slight elevation of the trigone.  It is usually more prominent in older men owing to enlargement of the posterior lobe of the prostate. 74 Fig. Urinary bladder and prostatic urethra 75  Clinical anatomy Cystocele—Hernia of Bladder  Loss of bladder support in females by damage to the pelvic floor during childbirth  laceration of perineal muscles or a lesion of the nerves supplying them  rupture of the fascial support of the vagina, the paracolpium  can result in collapse of the bladder onto the anterior vaginal wall. 76  Suprapubic Cystotomy  Surgical approach to the pubic symphysis for the introduction of in-dwelling catheters or instruments without traversing the peritoneum and entering the peritoneal cavity. 77  Urinary bladder  The main arteries supplying the bladder are branches of the IIA  The superior vesical arteries  Supply anterosuperior parts of the bladder.  In males, the inferior vesical arteries  Supply the fundus and neck of the bladder.  In females, the vaginal arteries  Replace the inferior vesical arteries and send small branches to posteroinferior parts of the bladder.  The obturator and inferior gluteal arteries  Also supply small branches to the bladder. 78  Urinary bladder The veins draining blood from the bladder  The veins form the vesical venous plexus which drains into the internal iliac vein.  In males, the vesical venous plexus  It is continuous with prostatic venous plexus and combined plexus complex envelops the fundus of the bladder and prostate, the seminal glands, the ductus deferentes, and the inferior ends of the ureters.  It also receives blood from the deep dorsal vein of the penis, which drains into the prostatic venous plexus.  It mainly drains through the inferior vesical veins into the internal iliac veins  It may drain through the sacral veins into the internal vertebral venous plexuses.  In females, the vesical venous plexus  Envelops the pelvic part of the urethra and the neck of the bladder  Receives blood from the dorsal vein of the clitoris, 79 and  Urinary bladder Lymph Drainage- Internal and external iliac nodes. Innervation of Bladder Parasympathetic fibers  Arise as the pelvic splanchnic nerves from the second, third, and fourth sacral nerves.  They pass through the inferior hypogastric plexuses to reach the bladder wall.  Stimulate contraction of the detrusor muscle of the bladder wall.  Inhibit the action of the internal urethral sphincter. Sympathetic fibers  Are conveyed from inferior thoracic and upper lumbar spinal cord (T11-L2 or L3 spinal cord levels) levels to the vesical (pelvic) plexuses primarily through the hypogastric plexuses and nerves.  Inhibit contraction of the detrusor muscle of the bladder wall.  Stimulate closure of the internal urethral sphincter to prevent reflux of semen into the bladder. 80  Urinary bladder Visceral afferent fibers  Conveying reflex information and pain sensation from subperitoneal viscera (inferior to pelvic pain line) follow parasympathetic fibers retrogradely to the S2-S4 spinal ganglia  Those conducting pain from the bladder roof (superior to the pelvic pain line) follow sympathetic fibers retrogradely to the T11-L2 or L3 spinal ganglia. FIG -Innervation of bladder and urethra 81  PROXIMAL (PELVIC) MALE URETHRA  The male urethra is a muscular tube (18-22 cm long).  It conveys urine from the internal urethral orifice of the urinary bladder to the external urethral orifice  It also provides an exit for semen (sperms and glandular secretions).  For descriptive purposes, the urethra is divided into four parts  Intramural (preprostatic) part  Prostatic urethra  Intermediate (membranous) part  Spongy urethra  The pelvic male urethra includes  Intramural (preprostatic) part  The preprostatic part of the urethra  it is about 0.5- 1 cm long  It extends from the base of the bladder to the prostate  It is surrounded by internal urethral sphincter  It is a circular cuff of smooth muscle fibers  Its contraction prevents retrograde movement of semen into the bladder during ejaculation.  The prostatic part of the urethra  It is 3 to 4 cm long  It is surrounded by the prostate.  It is a part of urethra where the connection between the urinary and reproductive tracts in men occurs  The urethral crest  a longitudinal midline fold of mucosa in this region.  The prostatic sinus  The depression on each side of the urethral crest  the ducts of the prostate empty into these two sinuses  The seminal colliculus  a circular elevation formed along Midway the urethral crest  In men, it is used to determine the position of the prostate gland during transurethral transection of the  The prostatic part of the urethra  The prostatic utricle  A small blind-ended pouch that opens onto the center of the seminal colliculus.  On each side of the prostatic utricle is the opening of the ejaculatory duct.  Arterial Supply and Venous Drainage of Proximal Male Urethra. Arterial supply to the proximal parts of the urethra  by prostatic branches of the inferior vesical and middle rectal arteries.  Arterial Supply and Venous Drainage of Proximal Male Urethra. The veins from the proximal two parts of the urethra  drain into the prostatic venous plexus.  Innervation of Proximal Male Urethra.  The nerves are derived from the prostatic plexus (mixed sympathetic, parasympathetic, and visceral afferent fibers).  The prostatic plexus is one of the pelvic plexuses (an inferior extension of the vesical plexus) arising as organ-specific extensions of the inferior hypogastric plexus. FIG. Innervation of bladder and urethra.  FEMALE URETHRA  It is approximately 4 cm long and 6 mm in diameter.  It passes anteroinferiorly from the internal urethral orifice of the urinary bladder to the external urethral orifice.  The musculature surrounding the internal urethral orifice of the female bladder is not organized into an internal sphincter.  In females, the external urethral orifice is located in the vestibule directly anterior to the vaginal orifice.  The urethra passes with the vagina through the pelvic diaphragm, external urethral sphincter, and perineal membrane.  FEMALE URETHRA  The paraurethral glands (or Skene glands)  Urethral glands are present, particularly in the superior part of the urethra.  One group of glands on each side of urethra  These glands have a common paraurethral duct, which opens (one on each side) near the external urethral orifice.  The inferior half of the urethra is located in the perineum  FEMALE URETHRA  Blood is supplied to the female urethra by  the internal pudendal and vaginal arteries  The veins follow the arteries and have similar names  FEMALE URETHRA Innervation of Female Urethra.  The nerves to the urethra arise from the vesical (nerve) plexus and the pudendal nerve.  Visceral afferents from most of the urethra run in the pelvic splanchnic nerves, but the termination receives somatic afferents from the pudendal nerve.  Both the visceral and the somatic afferent fibers extend from cell bodies in the S2-S4 spinal ganglia.