Human Anatomy - Pelvis PDF

HUMAN ANATOMY PART II PELVIS BY Jerzy Gielecki M.D, Ph.D Anna Żurada M.D, Ph.D Lab. session 2 1. THE PERINEUM......................................................................................... 1.1. Boundaries of the perineum.........................................................................

HUMAN ANATOMY PART II PELVIS BY Jerzy Gielecki M.D, Ph.D Anna Żurada M.D, Ph.D Lab. session 2 1. THE PERINEUM......................................................................................... 1.1. Boundaries of the perineum............................................................................... 2. THE PELVIC DIAPHRAGM........................................................................ 2.1. Structure of the pelvic diaphragm.................................................................... 2.2. Fascia enclosing the pelvic diaphragm.............................................................. 3. THE UROGENITAL DIAPHRAGM............................................................. 3.1. The base of the urogenital diaphragm.............................................................. 3.2. The muscular layer.............................................................................................. 4. THE DEEP PERINEAL POUCH................................................................. 5. MUSCLES ASSOCIATED WITH THE EXTERNAL GENITAL ORGANS................................................................................................. 6. THE SUPERFICIAL PERINEAL FASCIA................................................... 7. THE SUPERFICIAL PERINEAL POUCH................................................... 8. THE ISCHIOANAL FOSSA......................................................................... 8.1. Boundaries of the fossa....................................................................................... 8.2. Contents of the fossa........................................................................................... 9. ARTERIAL SUPPLY OF THE PERINEUM................................................. 10.INNERVATION OF THE PERINEUM........................................................ 20 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 11.VENOUS DRAINAGE OF THE PERINEUM.............................................. 12.HOMOLOGY OF STRUCTURES IN THE MALE AND FEMALE PERINEUM.................................................................................................... Male reproductive organs 13. MALE INTERNAL GENITAL ORGANS................................................... 13.1. The testes................................................................................................................ 13.2. The epididymis....................................................................................................... 13.3. The ductus deferens.............................................................................................. 13.4. Arterial supply of the testis, epididymis and ductus deferens.......................... 13.5. Venous drainage of the testis, epididymis and ductus deferens....................... 13.6. Lymphatic drainage of the testis, epididymis and ductus deferens................. 13.7. Innervation of the testis, epididymis and ductus deferens................................ 13.8. The spermatic cord................................................................................................ 14. MALE EXTERNAL GENITAL ORGANS.................................................. 14.1. The scrotum........................................................................................................... 14.2. Arterial supply of the scrotum............................................................................. 14.3. Innervation of the scrotum................................................................................... 14.4. The penis................................................................................................................ 14.5. Arterial supply of the penis.................................................................................. 14.6. Venous drainage of the penis............................................................................... 14.7. Lymphatic drainage of the penis......................................................................... J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 21 15. ACCESSORY GLANDS IN MALE REPRODUCTIVE SYSTEM.............. 15.1. The prostate........................................................................................................... 15.2. Arterial supply of the prostate............................................................................. 15.3. Venous drainage of the prostate.......................................................................... 15.4. Lymphatic drainage of the prostate.................................................................... 15.5. The bulbourethral glands..................................................................................... 15.6. The seminal vesicles.............................................................................................. 15.7. Arterial supply of the seminal vesicles................................................................ 15.8. Innervation of the seminal vesicles...................................................................... 22 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 1. The perineum The perineum (perineum) is a diamond shaped area represented by the lowest region of the trunk, which is located between the thighs and the lower part of the buttocks. 1.1. Boundaries of the perineum The perineum and the pelvic outlet share the same ligamentous and osseous boundaries:  anterior - pubic symphysis,  posterior - the coccyx,  anterolateral - on each side, the ischiopubic rami and ischial tuberosities,  posterolateral - on each side, tuberosities of ischium and the sacrotuberous ligaments. The perineal region is normally divided into an anterior and a posterior triangle by an imaginary line which joins the anterior regions of the ischial tuberosities (linea interischialica). a. The urogenital triangle (trigonum urogenitale), located in front of the line, contains the genitalia and the terminal region of the urinary tract. b. The anal triangle (trigonum anale) posterior to the line, contains the anal canal and anus. Pubic symphysis Obturator foramen Ischiopubic rami Urogenital triangle * A Anal canal B * * Ischial tuberosity Anal triangle behind line A-B Sacrotuberous ligament Sacrum and coccyx Fig. 2.1. The perineal region J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 23 2. The pelvic diaphragm The funnel-shaped pelvic diaphragm separates the pelvic cavity (above) from the perineum. Iliac crest Iliacus muscle Psoas major muscle Cavity of pelvis Rectum Acetabulum Obturator internus muscle Levator ani muscle Ischiorectal fossa Anal canal Fig. 2.2. Coronal section through the posterior part of the pelvis. 2.1. Structure of the pelvic diaphragm The pelvic diaphragm (diaphragma pelvis) is formed by two muscles: a. The levator ani muscle (musculus levator ani), which can be subdivided into three parts:  the puborectalis muscle (musculus puborectalis) is U-shape muscular sling around the anorectal junction. Some fibers of this muscle constitute the levator prostatae and pubovaginalis, 24 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd  the pubococcygeus muscle (musculus pubococcygeus), which is the main part of the levator ani muscle (origin: the pubis; insertion: the coccyx and anococcygeal ligament),  the iliococcygeus muscle (musculus iliococcygeus) arises on each side of the tendinous arch of the obturator fascia, passes medially and posteriorly, and attaches to the coccyx and to the anococcygeal ligament. b. The coccygeus muscle (musculus coccygeus) is situated against the posterior part of the iliococcygeus muscle and it forms the smaller part of the pelvic diaphragm. Pubic tubercle Pubic symphysis Puboprostatic ligaments Obturator nerve, artery and vein Prostate and urethra Obturator internus muscle Levator ani muscle Tendinous arch of obturator fascia Junction of rectum and anal canal Coccygeus muscle Spine of ischium Piriformis muscle Sacrum and coccyx Fig. 2.3. The pelvic diaphragm. The pelvic diaphragm is an elastic sling, which is formed by the combined musculature of the levator ani muscles (puborectalis, pubococcygeus and iliococcygeus muscles) with the coccygeus muscle. The abrupt transition from rectum to anus is represented by the fine line where the puborectalis muscle encircles the rectum. The terminal region of the anal canal is surrounded by voluntary (under human control) muscles known as the external anal sphincter. The external anal sphincter consists of a superficial and a deep portion. The fusiform superficial sphincter surrounds the terminal part of the involuntary internal anal sphincter. Anteriorly, it is attached to the perineal body and bulbospongiosus muscle, while posteriorly it is firmly anchored to the coccyx. The deep portion of the external anal sphincter is circular in shape and gains its support J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 25 by fusing with the levator ani muscle superiorly. In the absence of defecation and/or passage of flatus, the anal opening is kept in a closed position by the action of the voluntary anal sphincters. The pelvic diaphragm constitutes the pelvic floor and supports pelvic viscera. Acting together with the muscles of the abdominal wall, the levator ani muscle and coccygeus muscle compress the abdominal and pelvic contents. 2.2. Fascia enclosing the pelvic diaphragm The pelvic diaphragm is enclosed between two layers of the fascia: a. The superior fascia of the pelvic diaphragm (fascia diaphragmatis pelvis superior), which covers superior surface of the pelvic diaphragm, continues laterally as the pelvic parietal fascia (fascia pelvis parietalis), a continuation of the internal abdominal fascia, transversal fascia and the obturatory fascia (fascia obturatoria). b. The inferior fascia of the pelvic diaphragm (fascia diaphragmatis pelvis inferior), covers the inferior surface of the levator ani muscle, and the medial wall of the ischioanal fossa. 3. The urogenital diaphragm The urogenital diaphragm - U.G., (diaphragma urogenitale) is a three layer structure (fascia, muscle, fascia) filling the triangular area bordered by the ischiopubic rami. The U.G. diaphragm is traversed by the membranous urethra in the male and by the urethra and vagina in the female. 3.1. The base of the urogenital diaphragm The base, the free-border of the triangle, is formed by the fusion of two fascia layers: a. The posterior region of the inferior fascia of the U.G. diaphragm - perineal membrane, (fascia diaphragmatis urogenitalis inferior), is a relatively thick fascia, and it is derived from the muscles it encloses (deep transverse perinei muscles and the sphincter urethrae muscle). Previously it was noted that this layer also forms the roof of the superficial perineal pouch (space). This membrane is pierced by the urethra and ducts of the bulbourethral glands in the male and by the urethra and vagina in the female. Additional passages are encountered for the nerves and vessels subserving structures of the superficial perineal pouch located external to this membrane. b. the posterior border of the superior fascia of the U.G. diaphragm (fascia diaphragmatis urogenitalis superior), is derived from the endopelvic fascia, perhaps from its continuity with the fascia of the obturator internus muscle. The superior fascia forms the floor of the anterior recess of the ischioanal fossa. This fascial layer and the extent of the fatty layer within the anterior recess was probed by digital examination in a previous dissection (see ischioanal fossa, below). 26 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd The posterior free-border of the U.G. diaphragm corresponds to the imaginary line interconnecting the ischial tuberosities to split the perineum into its two triangles. The apex of the triangle does not reach the pubic symphysis. Instead, the union of the anterior region of the two fascial layers (inferior and superior fascia of the U.G. diaphragm) forms the transverse perineal ligament. 3.2. The muscular layer The muscular layer, intermediate in position, is formed by skeletal muscles: a. The paired deep transverse perineus muscles (musculus perinei transversus profundus), which are attached to the medial surfaces of the ischial rami and pass transversely into the perineal body. b. The sphincter urethrae muscle (in male, musculus sphincter urethrae) or the urethrovaginal sphincter muscle (in female, musculus urethrovaginalis). In male, the latter muscle covers the bulbourethral glands (of Cowper) located on each side of the membranous urethra. The ducts of these glands perforate the perineal membrane to drain the seminal fluid (secreted by the bulbourethral glands) into the bulb of the penil urethra. In female the urethrovaginal sphincter muscle compress the vagina and urethra. 4. The deep perineal pouch The deep perineal pouch or the deep perineal space, (spatium perinei profundum) is a narrow flat space lined above and below by the superior and inferior fascial layers of the U.G. diaphragm. The two layers of the fascia are attached laterally to the pubic arch and join each other at the apex of the triangle and also posteriorly at the base of the triangle. The narrow interfascial region of the U.G. diaphragm is neither a pouch, nor a space, since it is packed with the following contents in the anatomy of the male and female (see below): 4.1. Contents of the deep perineal pouches in the two sexes STRUCTURE  Deep transverse perineus muscle  Compresses vagina  Sphincter urethra muscle  Compresses urethra  Compresses vagina  Urethra (membranous portion)  Vagina  Bulbourethral glands (of Cowper)  Drain into urethra (penile)  Branches of pudendal nerve to:  Muscles of deep perineal pouch  Dorsum of penis or clitoris MALE J. St. Gielecki and A. Żurada -HUMAN ANATOMY + + + + + + FEMALE + + + + + + + - + + Copyright © 2019 MedRadEd 27 (dorsal nerve of penis/clitoris)  Branches of internal pudendal a.  artery to the bulb (of penis)  artery to the vestibule  urethral artery  deep artery of penis/clitoris  dorsal artery of penis/clitoris  Tributaries of internal pudendal vein 5. + + + + + + + + + + + + Muscles associated with the external genital organs a. The superficial transverse perineus muscle (musculus transversus perinei superficialis), which is covered by the deep (muscular) fascia, is located along the inferior surface of the posterior "free-border" of the urogenital diaphragm. The muscle extends between the ischial tuberosities and the perineal body. b. The ischiocavernosus muscle (paired muscle, musculus ischiocarvenosus), surrounds the crura of the penis/clitoris. These erectile bodies are attached along the ischiopubic rami and are superficially covered, in sequence, by ischiocavernosus muscle and its fascia (also known as the deep fascia or muscular fascia). c. The bulbospongiosus muscle (musculus bulbospongiosus) and its fascia cover the bulb of the penis. The unpaired corpus spongiosum penis is traversed by the spongy portion of the urethra (male only). The superficial aspect of the bulb is covered by the paired bulbospongiosus muscles, which are united along the midline. Superficially, a fascial layer covers the muscles. The posterior end of the bulb is penetrated by the urethra which crosses the length of the corpus spongiosum as the spongy urethra to open at the glans penis. The perineal body, also known as the central tendinous point of the perineum (centrum tendineum perinei), is a fibromuscular structure attached to the middle of the posterior border of the urogenital diaphragm. This fibrous thickening is formed by the fusion of fascia and fibers of the musculature of the urogenital diaphragm (sphincter urethrae and deep transverse perineal muscle) with muscular fasciculi from the pelvic diaphragm (pubococcygeus muscle of levator ani muscle) and perineal attachment of the external anal sphincter muscle. The perineal body has significance in obstetric and gynecological procedures of the perineal area. 6. The superficial perineal fascia After reflecting the skin of the perineum, note that the superficial perineal fascia (fascia perinealis superficialis), like that of the abdominal wall, consists of a superficial adipose (fatty) layer and a deeper fibrous (membranous) layer. The fatty layer of this region continues up from the thighs and posteriorly into the ischioanal (ischiorectal) fossa (the fatty tissue of the anal triangle which is concentrated on the lateral aspect of the anus). Upon reaching the scrotum and skin of penis, the fatty layer diminishes to a monocellular film, which blends with the fibrous layer of the superficial 28 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd perineal fascia. In the lower abdominal and perineal region of the male, the subcutaneous fibrous layer displays several extensions, fusions and attachments with fascia of surrounding structures resulting in multiple eponyms attributed to the same (fibrous) layer: a. superficial abdominal fascia (fibrous layer of Scarpa), b. superficial fascia around the penis, b. Darto's fascia/ muscle lining the skin of the scrotum, c. Colle's fascia over the superficial perineal pouch. Along the midsagittal plane, the fibrous layer of the subcutaneous perineal fascia attaches along the septum of the scrotum and to the midline of the fibrous raphe lining the superficial aspect of the bulbospongiosus muscle. Laterally, it attaches to the ischiopubic rami and posteriorly it blends with the fascial lining of the free border of the urogenital diaphragm. These fascial attachments are often verified clinically in the perineum of the male by regional entrapment of extravasated body fluids following injuries of the erectile tissue and/or urethra. The attachments of this fascial layer in the female perineum, differ only in respect to their medial attachment along the intervening vaginal walls. 7. The superficial perineal pouch The superficial perineal pouch (spacium perinei superficiale) represents a specific region of the urogenital triangle bounded inferiorly by the fibrous layer of the superficial perineal fascia and superiorly by the perineal membrane (inferior fascia of the urogenital diaphragm). Table 7.1. Contents of the superficial perineal pouches in the two sexes Structure  central tendinous point of the perineum +  superficial transverse perineus muscle  root of the penis / clitoris  bulb of the penis / the bulbs of the vestibule +  proximal part of the spongy urethra  contents of the scrotum  greater and lesser vestibular glands  branches-internal pudendal vessels & nerves + 8. Male + + + + - Female + + + + + + + The ischioanal fossa The borders of the ischioanal fossa /ischiorectal fossa, (fossa ischiorectalis) are best observed after splitting the pelvis to study the blood vessels and nerves associated with the muscle and fasciae of the lateral pelvic walls. The canal is formed by splitting the inferior margin of the fascia of the obturator J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 29 internus muscle along the lateral wall of the fat-filled ischioanal fossa. The pudendal canal courses about 4 to 5 cm above the medial aspect of the ischial tuberosity to conduct the vessels mentioned above, and the nerve to the posterior aspect of the urogenital (U.G.) diaphragm. 8.1. Boundaries of the ischioanal fossa  the base is formed by the deep fascia and perineal skin,  anteriorly it continues into the anterior recess of the ischiorectal fossa (superior to the urogenital diaphragm) ,  medially - by the inferior fascia of the urogenital diaphragm,  laterally - by the obturatory fascia (contains the pudendal canal (canalis pudendalis) formed by two layers of the obturatory fascia , it contains the internal pudendal artery & vein and pudendal nerve),  apex is located about 6 cm above the ischial tuberosity. 8.2. Contents of the ischioanal fossa  the inferior rectal artery (arteria rectalis inferior) branch of the internal pudendal artery,  the inferior rectal nerves (nervi rectales inferiores) branch of the internal pudendal nerve,  fatty and connective tissue. 9. Arterial supply of the perineum The perineum is supplied by the branches of one artery - the internal pudendal artery. The superficial perineal veins are tributaries of the femoral vein (which drains into the external iliac vein) while the deeper veins collect into the internal iliac vein (via the prostatic or vesical plexus and the internal pudendal vein). The internal pudendal artery (I.P.A., arteria pudenda interna), a branch of the internal iliac artery (arteria iliaca interna), leaves the cavity of the true (lesser) pelvis by passing laterally, between the piriformis and coccygeus muscle, to reach the inferior rim of the greater sciatic foramen. Next, the vessel loops around the external aspect of the ischial spine and/or attachment of sacrospinous ligament to enter the lesser sciatic foramen by which it gains access to the perineal structures. At the 30 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd posterior aspect of the medial wall of ischial tuberosity, the I.P.A., the accompanying veins, and the pudendal n. (P.N.), enter the pudendal canal. Branches of the (I.P.A.) (the I.P.A. has the same distribution and virtually the same branches as the pudendal nerve): a. Branches given within the length of the pudendal canal:  inferior rectal artery (arteria rectalis inferior) passes through the fat of the ischioanal fossa to supply the external anal sphincter mm. and the skin of the anal region,  perineal artery (arteria perinealis) runs over the superficial transverse perineus muscle and passing between the bulbospongiosus and ischiocavernosus muscles supplies all three muscles of the superficial perineal pouch. The artery gives off a posterior scrotal/labial branch, which provides afferent branches to the posterior wall of scrotum (skin and tunica dartos). The I.P.A. next reaches the posterior border of the deep perineal pouch where it may stay superficial to the inferior membrane of the U.G. diaphragm (perineal membrane), or most likely, it passes above the perineal membrane to enter the deep perineal pouch (D.P.P.). Within the D.P.P. the I.P.A. breaks into its terminal branches as follows: b. Branches given off within the deep perineal pouch: (next page)  branches to musculature of the deep perineal pouch (sphincter urethrae and deep transverse perineus muscles, in the male; mixture of fibers of sphincter urethrae and vagina in the female).  artery to the bulb of penis /or vestibule in female (arteria bulbi penis aut arteria bulbi vestibuli) gives off a branch to bulbourethral gland (male), then the parent artery passes through the perineal membrane, enters the bulb (penis or vestibule) to supply the bulb and posterior segment of the corpus spongiosum penis.  urethral artery (arteria urethralis) pierces the membrane to enter the corpus spongiosum, which it follow to the glans of penis,  deep artery of the penis/clitoris (arteria profunda penis /clitoridis), pierces the membrane to enter the center of each corpus cavernosus penis (clitoris),  the dorsal artery of the penis/clitoris (arteria dorsalis penis /clitoridis) leaves the anterior region of the U.G. diaphragm, passes through the suspensory ligament of the penis (clitoris) to enter the dorsal aspect of the penis where it runs deep to Buck's fascia (derived from fascia of bulbospongiosus muscle). 10. Innervation of the perineum The perineum is supplied by the branches of one nerve - the pudendal nerve. Branches of the pudendal nerve are: a. inferior rectal nerve (nervus rectalis inferior) - to the external anal sphincter, b. perineal nerves (nervi perineales) with its: - deep branch (or motor fibers) to all perineal muscles, - posterior scrotal (labial) branches (sensory). J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 31 c. dorsal nerve of the penis/clitoris (nervus dorsalis penis/clitoris) to erectile tissue and skin. 11. Venous drainage of the perineum Tributaries of the external iliac vein is: superficial dorsal vein of penis / clitoris (vena dorsalis superficialis penis/clitoridis) is a single structure, which passes towards the pubic symphysis, without accompanying arteries and/or nerves, to drain, by splitting into a right and left branch, into the external pudendal vein (a tributary of the greater saphenous vein or of femoral vein). Tributaries of the internal iliac vein (vena iliaca interna). a. deep dorsal vein of penis/clitoris (vena dorsalis penis/clitoridis) - on each side the vein is bordered by a dorsal artery (of penis) and lateral to the artery, branches of the dorsal nerve of penis (clitoris). The deep dorsal vein (of penis/clitoris) does not course through the deep perineal pouch. The vein leaves the penis (clitoris) to pass between the transverse perineal and arcuate pubic ligaments to drain into the prostatic plexus of veins (male) or vesical plexus of veins (female), b. deep vein of penis/clitoris (vena penis/clitoris profunda) - collects blood from the cavernous tissue before draining into the internal pudendal vein from which blood passes into the prostatic or vesical venous plexus, c. rectal plexus of veins (plexus venosus rectalis). 12. Homology of structures in the male and female perineum MALE PERINEUM FEMALE PERINEUM Bulbourethral glands (Cowper's) Greater vestibular glands (Bartholin's) Scrotum Labia majora Corpus spongiosum Labia minora and the bulb of the vestibule Penis Urethra Prostatic (via prostate gland) Membranous (via UG diaphragm) Spongy (via corpus spongiosum) 32 Clitoris Urethra J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 13. Male internal genital organs 13.1. The testes The testes are paired, ovoid in shape, male reproductive organs, which are suspended by the spermatic cords in the scrotum. The testis (testis) is covered by the tunica albuginea (tunica albuginea). The testes are also covered by visceral and parietal layers of the tunica vaginalis. The visceral layer of the tunica vaginalis (lamina visceralis) covers tunica albuginea testis and epididymis. A testis has:  two surfaces - medial and lateral  two margins - anterior and posterior  two ends - superior and inferior a. The septa testis (septula testis) divides the stroma testis into lobules. The stroma testis is composed of the seminiferous tubules (tubuli seminiferi). The main function of the testes is production of the male gamete cells (spermatozoa) and male sex hormones called androgens. b. Descent of the testes The testes enter the inguinal canal after birth and descend through the canal into the scrotum. Normally the stalk of the processus vaginalis obliterates after birth and one part surrounds the testis. This part is called the tunica vaginalis. 13.2. The epididymis The epididymis (epididymis) is a structure located on the superior and posterolateral surfaces of the testis (comma-shaped). It is composed of :  the head (superior part) - which is composed of the lobules of the epididymis  the body - contains the efferent ductules J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 33  the tail - continuous as the ductus deferens 13.3. The ductus deferens The ductus deferens (ductus deferens) is a muscular tube which conveys the sperm cells from the tail of the epididymis (of testes) to the point of union with the ducts of the seminal vesicles. Both, the ductus deferens and excretory duct form the ejaculatory duct (ductus ejaculatorius). Along its ascent (40-45 cm), each ductus deferens passes through the spermatic cord and inguinal canal to enter the cavity of the lesser (true) pelvis. The ductus deferens can be divided into four parts: a. testicular part (pars testicularis) accompanies epididymis b. portion in the spermatic cord (pars funicularis) ascends in the spermatic cord, c. inguinal part (pars inguinalis) passes through the inguinal canal, d. pelvic part (pars pelvica) passes along the lateral wall of the pelvis and turns into the urinary bladder. Near the bladder the ductus deferens enlarges and forms the ampulla of the ductus deferens (ampulla ductus deferentis). In cross sections, this retroperitoneal tube passes from lateral to medial over the ureter to reach the posterior aspect of the bladder. (The mnemonic of this relation is: bridge [ductus] over water [ureter]). The ureters descend medially and parallel to the saccules of the seminal vesicles. 13.4. Arterial supply of the testis, epididymis and ductus deferens a. the testicular artery (arteria testicularis) from the abdominal aorta, b. the artery of ductus deferens (arteria ductus deferentis) from the internal iliac artery or the umbilical artery, c. the cremasteric artery (arteria cremasterica) from the inferior epigastric artery. 13.5. Venous drainage of the testis, epididymis and ductus deferens a. pampiniform plexus (plexus pampiniformis) b. right and left testicular veins (venae testiculares dextrae and sinistrae) which drain into the inferior vena cava and left renal vein 13.6. Lymphatic drainage of the testis, epididymis and ductus deferens The lymph from the testis and epididymis drains into the superficial inguinal lymphatic nodes (nodi lymphatici inguinales superficiales). 34 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 13.7. Innervation of the testis, epididymis and ductus deferens Sympathetic fibers from the testicular plexus (from the celiac plexus) and the parasympathetic from CN X (nervus vagus). 13.8. The spermatic cord The spermatic cord (funiculus spermaticus) begins at the deep inguinal ring, runs through the inguinal canal, and ends at the posterior border of the testis. Contents of the spermatic cord: a. the ductus deferens, b. the testicular artery, c. the artery of the ductus deferens, d. the cremasteric artery, e. the pampiniform plexus, f. the genital branch of the genitofemoral nerve, g. the sympathetic and parasympathetic fibres of the ductus deferens, h. associated lymph vessels. 14. Male external genital organs 14.1. The scrotum The scrotum (scrotum) consists of a few layers, which are presented below in order from the outermost to the innermost one: a. the skin, b. the external spermatic fascia (fascia spermatica externa), which contains the dartos muscle (tunica dartos), is the continuation of the cutaneous fascia of the anterior abdominal wall; the superficial fascia divides the scrotum into two halves: the left and right half, it is indicated by the scrotal raphe, c. the cremasteric fascia (fascia cremasterica) is the continuation of the superficial fascia of the anterior abdominal wall, e. the cremaster muscle (musculus cremaster) is the continuation of the the internal oblique and transverse muscle aponeurosis, J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 35 f. the internal spermatic fascia (fascia spermatica interna) is a continuation of the abdominal transversal fascia. 14.2. Arterial supply of the scrotum a. anterior scrotal branches (rami scrotales anteriores) from the external pudendal arteries, b. posterior scrotal branches (rami scrotales posteriores) from the internal pudendal artery. Veins correspond to the arteries. 14.3. Innervation of the scrotum a. genitofemoral nerve (nervus genitofemoralis) supplies the dartos muscle and the cremaster muscle, b. anterior scrotal nerves (nervi scrotales anteriores) from the ilioinguinal nerve, c. posterior scrotal nerves (nervi scrotales posteriores) from the pudendal nerve. Fig. 2.4. Male genital organs. 14.4. The penis 36 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd The penis (penis) is a male organ of copulation (homologous with the clitoris in the female), and is the common way out for urine and semen. The penis can be divided into two portions: a. the root of the penis, b. the body of the penis, c. glans penis. The root of the penis begins near the inferior region of the pubic symphysis where the three tubes separate into the left and right cavernous body of penis (corpus cavernosum penis) and the spongious body of penis (corpus spongiosum penis). The separation of the two corpora cavernosa forms the crura (lat. pl. of crus, a leg) of the penis. The left and right crus is covered by the corresponding ischiocavernosus muscle (musculus ischiocavernosus) which, in turn, is superficially lined by the muscular fascia. The root portion of corpus spongiosum is slightly enlarged to form the bulb of the penis (bulbus penis). Located between the corpora cavernosa, the bulb is firmly attached to the perineal membrane (inferior fascia of the urogenital diaphragm). The corpus spongiosum contains the spongy urethra (pars spongiosa urethrae). The body of the penis has no muscles and consists of the corpora cavernosa and the corpus spongiosum. The root and body of the penis are composed of the cavernous erectile tissue. The glans of penis is located distally, it is an expanded part of the corpus spongiosum, and enters there the external orifice of the urethra (near a tip of the glans). There, on the glans is the highest concentration of the sensory nerve endings in comparison with the rest of the penis. Pubic symphysis Corpus cavernosum penis Corpus spongiosum penis Bulbospongiosus muscle Ischiocavernosus muscle Superficial transverse perineal muscle Sphincter ani externus muscle Coccyx Fig. 2.5. Inferior aspect of the male perineum. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 37 14.5. Arterial supply of the penis Arteries, which supply the penis are branches from the internal pudendal artery (arteria pudenda interna): a. the dorsal arteries of the penis (arteriae dorsales penis) pass on both sides of the dorsal vein, b. the deep arteries of the penis(arteriae profundae penis) pierce the crura and pass within the corpora cavernosa; they can be observed in a cross section of the cavernous bodies, c. the artery of the bulb (arteria bulbi vestibuli), d. the artery of the urethrae (arteria urethralis). 14.6. Venous drainage of the penis a. The unpaired deep dorsal vein of the penis (vena dorsalis penis profunda) is located deep to the deep fascia of the penis (Buck's fascia). On its lateral aspects the vein is accompanied by the left and right dorsal artery and nerve (of the penis). The deep dorsal vein receives blood from the cavernosus spaces and enters the lesser pelvis by passing between the arcuate pubic ligament (on the inferior aspect of the pubic symphysis) and the transverse perineal ligament (on the anterior region of the urogenital diaphragm). It drains into the prostatic plexus of veins (prostatic venous plexus, plexus venosus prostaticus). b. The paired superficial dorsal veins (venae superficiales dorsales penis) drain blood from the superficial coverings of the penis. These veins return blood into the external pudendal veins (venae pudendae externae ) and next into the femoral veins. c. The paired deep veins of the penis (venae profundae penis), which are located inside the corpora cavernosa, return blood into the internal pudendal vein (venae pudendae internae). 14.7. Lymphatic drainage of the penis a. Almost all lymph (except the glans penis) is returned into the superficial inguinal lymph nodes (nodi lymphatici inguinales superficiales). b. The lymph from glans penis is returned to the deep inguinal lymph nodes (nodi lymphatici inguinales profundi). 38 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd Fig. 2.6. The male urethra. 15. Accessory glands in the male reproductive system Neck of bladder Median lobe of prostate Prostate Prostatic utricle Levator ani muscle Urethra Fig. 2.7. Localization of the prostatic gland on the midsagittal section. J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 39 15.1. The prostate The prostate (prostata) is the largest accessory gland, and is located in the true pelvic cavity at the neck of the urinary bladder. Here it surrounds the first 4 cm of the male (prostatic) urethra. The normal prostate resembles a 20 – 30 g "buckeye nut", which measures about 4 cm at the base, 2 cm in its anterior to posterior length and 3 cm in height. The glans has : a. base - is penetrated by the urethra and related to the caudal region of the urinary bladder, b. apex - the inferior region of the glans, rests on the superior (deep) layer of the urogenital diaphragm, c. four surfaces:  anterior surface - is convex, it extends between apex and base,  posterior surface - triangular in shape, it is in contact with the ampulla of the rectum and can be easily palpated by examining with a finger in the rectum (per rectum examination),  two lateral surfaces. Usually the prostate is divided into three lobes: a. two lateral lobes - between them, on the posterior surface, a groove is marked in the midline plane by the ejaculatory ducts, b. the middle lobe is located between the ejaculatory ducts and the urethra, which are situated posteriorly to the uvula of the urinary bladder. The clinicians often divide the gland into five lobes which relate to the urethra:  the anterior lobe, in front of the urethra,  the posterior lobe, behind the urethra, inferior to the entrance of the ejaculatory ducts,  the median lobe, located posteriorly to the urethra and above the ejaculatory ducts,  the two lateral lobes unite the anterior and posterior lobes, and are penetrated by the ejaculatory ducts (union of ductus deferens with the duct of the seminal vesicle). Relations of the prostate The prostate is located in the true pelvis in the infraperitoneal space.  anteriorly - is located the pubic symphysis,  posteriorly - the rectum,  superiorly - the urinary bladder,  inferiorly - it is supported by the urogenital diaphragm,  laterally - the levator ani muscle. The supporting components of the prostate:  rectovesical ligament - extends between the rectum and the urinary bladder,  puboprostatic ligament - between the pubic symphysis and the prostate,  the urogenital diahragm,  the urethra - stabilizes with the urinary bladder and urogenital diaphragm. The prostate is enclosed in the fibrous capsule (true capsule), and also by outer capsule, which is the sheath from the pelvic fascia. Between them the prostatic venous plexus is situated. The alkaline secretion produced by the prostatic glandular tissue maintains the integrity of the sperm cells and 40 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd their mobility. It is transported by the prostatic ductules and ducts (about 30 in number), which enter into the prostatic sinus on both sides of the posterior wall of the urethra. Sacrum represented in pieces 1 Plane of brim of pelvis 2 3 4 1/3 Peritoneum Anterior abdominal wall 1/3 Bladder Pubic symphysis 1/3 Prostate 5 Coccyx Rectum Spincter urethrae Urethra Levator ani muscle Anal canal Fig. 2.8. Midsagittal section through the male pelvis. 15.2. Arterial supply of the prostate The prostate is supplied by branches from the internal iliac artery: a. the inferior vesical artery (arteria vesicalis inferior), b. the middle rectal artery (arteria rectalis medialis). 15.3. Venous drainage of the prostate J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 41 The prostatic veins form the prostatic venous plexus, which is located outside the true capsule, and drain mainly into the internal iliac vein. However, the prostatic venous plexus communicates also freely with the vesical venous plexus. 15.4. Lymphatic drainage of the prostate Most of lymph produced in the prostate is drained into the internal iliac and sacral lymphatic nodes (nodi lymphatici iliaci interni et nodi lymphatici sacrales). The enlargement of the middle lobe with advancing age often obstructs the flow of urine. This obstruction can be removed by insertion of a surgical instrument called the rectoscope into urethra. Sometimes the prostate is surgically removed, and that is called a prostectomy. 15.5. The bulbourethral glands Two yellowish bulbourethral glands - Cowper's glands (glandulae bulbo-urethrales) are situated posterolaterally to the membranous urethra in male. The bulbourethral glands are oval in shape (about 0,5-0,8 cm in diameter) have long ducts of the bulbourethral glands (ductus glandulae bulbo-urethralis) about 3.5-4.0 cm in length, which pass through the urogenital diaphragm, and open into the proximal part of spongy urethra. 15.6. The seminal vesicles The paired seminal vesicles (vesiculae seminales) resemble small bags (5 cm long, 2 cm in width and 1.5 cm thick) filled with raisins which rest upon the posterior border of the urinary bladder. The alkaline secretion produced by these glands is added to the seminal fluid - the seminal vesicles do not store sperm. The duct of each seminal vesicle narrows significantly near the prostate and joins the corresponding ductus deferens to form one of the two ejaculatory ducts, which enters the lateral lobe of the prostate. The fluid is expelled into the excretory duct during orgasm, when the seminal vesicles are contracted. 42 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd Relations of the seminal vesicles  the seminal vesicles lie parallely and laterally to the descending part of the vas deferens,  posteriorly:  the upper region of the vesicles is separated from the rectum by the intervention of peritoneal lining of the rectovesical pouch,  inferiorly, in the absence of this peritoneal pocket, the posterior surfaces of the vesicles are separated from the rectum by the connective tissue. Ductus deferens Seminal vessicle Prostate Pelvic diaphragm Fig. 2.9. Relations of the deferent ducts and the seminal vessicles (fundus of the urinary bladder). 15.7. Arterial supply of the seminal vesicles The arteries, which supply the seminal vesicles come from the inferior vesical arteries, artery of the ductus deferens and middle rectal artery. Veins, which drain the seminal vesicles are homologous with the arteries. 15.8. Innervation of the seminal vesicles J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd 43 The seminal vesicles receive sympathetic fibers from the inferior hypogastric plexus and parasympathetic fibers from the pelvic splanchnic nerves. 44 J. St. Gielecki and A. Żurada -HUMAN ANATOMY Copyright © 2019 MedRadEd