Paired kidneys are responsible for removal of useless products of protein metabolism and excess of salts and water from the blood. The kidneys in adult measure about 10-12 cm in length, 5-6 cm in width and 2.5 -3.5 cm in thickness.
The organs lay on the posterior abdominal wall (on the level between Th11-L3) and they are situated retroperitoneally (posteriorly to the peritoneum), both of them are in contact with the diaphragm (posterosuperiorly) and are capped by the adrenal gland (anteromedially). Each kidney is obliquely set because its upper pole is nearer the midline (3.5-4cm) than its lower pole (5.5-6 cm). Superior poles of both kidneys are protected by thoracic cage. The right kidney lies on the slightly lower level then the left one, due to the presence of the liver on the right side. The left kidney’s upper pole extends above the posterior segment of the eleventh rib. The superior pole of the right kidney extends above posterior segment of the right twelfth rib.
Each kidney (ren) is located: • on the ventral surface of the quadratus lumborum muscle • laterally to the psoas muscle and the vertebral column.
The kidney has:
upper & lower poles (extremitas seu polus superior et inferior),
anterior & posterior surface (facies anterior et posterior),
lateral (convex) & medial (concavity with renal sinus) margin (margo lateralis s. convexus et margo medialis s.concavus)
The concave medial border of the kidney contains the renal hilus (hilum, hilus renalis), through which the renal pelvis and vein leave the kidney, and also the renal artery enters there to the kidney. The hila are located about the level of the transpyloric plane. At the hilus opens medially the renal sinus, the cavity of the kidney.
The renal vessels and the renal pelvis, the distended pre-ureteric portion of the urinary tract, are arranged in the following order:
This layer arises from the prevertebral fascia. It divides into two layers:
anterior layer
posterior layer
The fascia splits inferiorly into two leaflets and fuse superiorly and lateraly for enclosing the kidney and suprarenal gland. It sourounds the kidney and suprarenal gland. The renal fat is associated with the kidney and it also sourounds kidney and suprarenal gland and it is called fat capsule (capsula adiposa). The renal fascia fuses around the renal vessels and forms the periuretral sheath.
The medulla is formed by 10 -20 renal pyramids. Every pyramid contains:
the proximal straight tubules (tubulus rectus proximalis)
the Henle’s loops (ansa Henlei)
the distal straight tubules (tubulus rectus distalis)
the collecting tubules
The collecting system of the kidney is composed of three elements:
minor calyces, which fuse and join to form 2-4 major calyces
major calyces, which fuse and join to form renal pelvis
the renal pelvis narrows to form the ureter
The urine empties into minor calyces from the collecting tubules. The minor calyces envelop the renal papillae and urine pierces the tip of the renal papillae.
The renal arteries (arteriae renales) arise from the lateral aspect of the abdominal aorta and divide into branches near the hilum. The left and right renal arteries arise usually between L1 and L2, just below origin of the superior mesenteric artery. The right renal artery passes posteriorly to the inferior caval vein.
The left and right renal arteries give rise to the inferior suprarenal arteries outside the kidney and the arterial twigs to the ureter.
The renal arteries divide into segmental arteries within the renal sinus.
The interlobar arteries arise from each segmental artery. Each interlobar artery enters a renal column. Each gives off the arcuate arteries, which run across the bases of the pyramids between the cortex and medulla.
The kidneys are supplied by the coeliac plexus, which gives fibres (sympathetic fibres from coeliac plexus and parasympathetic fibres from cranial nerve X) to the renal plexus.
The ureters are the excretory tubes which convey urine from the kidneys to the bladder. The ureters are thick-walled, muscular tubes in which peristaltic waves occur at that time when urine passes along the tube. They are 25-30 cm long. Each ureter descends retroperitoneally from the renal pelvis (L2) to the urinary bladder (S4).
Cours of each ureter has two stages:
abdominal part
pelvic part
In the abdomen, each ureter descends retroperitoneally and in its abdominal course the ureter courses anteriorly to the psoas major muscle, then crosses over the proximal part of the external iliac artery from lateral to medial side, to enter the cavity of the true pelvis.
The gonadal vessels cross anteriorly to the middle 1/3 of the ureters. The right ureter descends close to the right margin of the I.V.C. while the left ureter passes inferiorly under the descending colon. After crossing over the pelvic brim, near the sacral promontory (promontorium, level of L5/S1), the ureter enters the cavity of the true (lesser) pelvis. The pelvic portion of the ureter runs along the lateral wall of the true pelvis, then it turns medially to enter the posterior aspect (the fundus) of the urinary bladder.
In males, near the bladder, ductus deferens loops over the ureter to reach the seminal vesicles and prostate. In the mnemonic for this crossing over there is a “bridge” (ductus) over “water” (ureter). In females, the ureter passes deeply to the uterine vessels, near the ischial spine, a place of great danger during hysterectomy procedures.
Two suprarenal endocrine glands (glandulae suprarenales) are situated on the upper poles of the kidneys. They are asymmetrical.
The right gland is pyramidal in shape and lies in the front of the right crus of the diaphragm behind the inferior vena cava and bare area of the liver.
The leftgland is crescent and its lower end reaches the hilum of the kidney. It lies in the front of the left crus of the diaphragm, and behind the splenic vessels and the pancreas.
The main function of the highly muscular urinary bladder is storage of urine to an average capacity of 500 ml.
It is located within the true pelvic cavity, rests on the lining of the inner aspect of the pubis and floor of the pelvis. The superior surface of the empty bladder reaches the pubic crest, and as the organ fills with urine it distends superiorly into the abdominal cavity to reach, under extreme conditions, the umbilical region. The superior surface of the bladder is covered with a sheet of peritoneum which continues with the peritoneal reflections over the uterus, in the female, and along the upper anterior surface of the rectum in the male.
The bladder shape vary with the amount of the urine it contains and also is determined by organs, which are closlely related to it.
The apex (apex vesicae) – anterior end of the urinary bladder. The median umbilical ligament (remanat of the embryonic urachus) arises from the apex and (enclosed in the peritoneum) forms the median umbilical fold (pica umbilicalis mediana)
The neck – inferolateral part connecting the apex and the body
The body
The fundus of the urinary bladder (base) – posteroinferior surface.
The wall of the bladder consists of the muscular part (smooth muscles) and the mucous membrane.
Mucous membrane is loosly connected to the muscular layer exept the area located in the fundus, which is triangular in shape and is called trigone of the bladder (trigonum vesicae). The ureteric orifices are located in the two upper angels of the trigone of the bladder. The interureteric fold is sutuated horizontaly between them. In the lower angle of the trigone of the bladder there is the internal urethral orifice (ostium urethrae internum).
The smooth muscles of all layers form the detrusor muscle (musculus detrusor urinae). Fibres of all layers run toward to the neck of the bladder and form the internal sphincter (musculus sphincter vesicae).
The superior surface of the bladder in the male is covered by the peritoneum and comes in contact with coils of the small intestine. In the female, with an empty bladder, the superior surface of the organ is overlapped by the uterus.
The two inferolateral surfaces of the bladder are positioned against the fat-filled retropubic space which is traversed by a multitude of veins (prostatic or vesical tributaries of the internal iliac vein). The inferolateral surfaces of the bladder meet at the neck of the organ which relates to the prostate, in the male, and the pelvic diaphragms (pubococcygeal part of the levator ani muscles) in the female pelvis.
The posterior surface or the base of the bladder is related to the seminal vesicles and ampullae of ductus deferens and rectum in the male pelvis. In the female, the base relates to the anterior wall of the vagina and to the supravaginal part of uterine cervix.
All veins from bladder drain into the internal iliac vein and correspond to adequate arteries. The vesical venous plexus envelops the base of the bladder and prostate and comunicates freely with the prostatic plexus in male, the veins from the seminal vesicles, and ductus deferentes.
From the superior part of the bladder lymph drains into external iliac lymphatic nodes, and next to the common iliac nodes. From the inferior part of the bladder lymph drains into the internal lymphatic nodes, and next to the common iliac nodes.
The main function of the urethra is to convey urine from the bladder to the external environment – external urethral orifice, and to allow the passage of sperm between the prostate and the tip of the penis during ejaculation in male. In male it also provides seminal fluid. The male urethra is represented by a 15 – 20 cm long passage lined by a few types of epithelium. The normal transverse width of urethra, 5 to 6 mm, can be stretched up to 26 mm for examination of the urinary tract and bladder.
Prostatic part – 2.5 to 4.5 cm long, the prostatic urethra extends between the internal urethral orifice and the superior fascia of the urogenital diaphragm. It passes through the prostata downwards as a anteriorly concave curve. This part is the widest and dilatable part of the male urethra, which is narrowest in the superior and inferior segment of the prostatic urethra.
Spongy part – 14 to 15 cm – the longest part of the urethra passes through the root and body of the penis, within corpus spongiosum of the superficial perineal pouch
Pubic symphysis
Suspensory ligament of penis
Corpus cavernosum penis
Prepuce
Glans penis
External urethral orifice
Corpus spongiosum penis
Scrotum
Spongy part of urethra
Bulb of penis
Intermediate part
Prostatic urethra
Intramural part
Internal orifice
Urinary bladder
Prostate
Course and relations of the male urethra.
Prostate
Ejaculatory duct
Prostatic ducts
Proximal part
Urethral crest
Seminal colliculus
Prostatic utricle
Distal part
The beginning part of the male urethra opened and seen from above.
The bulbourethral glands of the male are located on either side of the urethra as the latter passes between the muscular fasciculi of the sphincter urethrae muscle of the deep perineal pouch.
The female urethra is a 4 cm long and 5 mm width muscular tube. The superior part of the female urethra is coresponding to the prostatic part of the male urethra and inferior part is adequate to the membranaceus part. The female urethra originates in the apex of the urinary bladder, passes posteriorly, and next inferiorly to the pubic symphysis. The female urethra lies anteriorly to the vagina and ends in the vestibule of the vagina as external urethral orifice, which is located between the labia minora, below the clitoris and in front of the vaginal opening. It is surrounded there by the sphincter urethrae muscle. The female urethra with the vagina passes through the uretrogenital diaphragm and the perineal membrane.
The female urethra can be divided into four parts:
Intramural (intraparietal) portion – inside the bladder’s wall
Supradiaphragmatic portion – above the uretrogenital diaphragm, runs along the anterior wall of the vagina
Diaphragmatic portion – surrounded by the sphincter urethrae muscle
Infradiaphragmatic portion – between the paraurethral glands
There are the paraurethral glands on each side of the female urethra, which are homologous to the prostate in male. The ducts from the paraurethral glands open near the external urethral orifice in the vestibule of the vagina.
It’s origin is located in front to the sacroiliac joint on the lewel fifth lumbar vertebra as the terminal branch of the common iliac artery.
End of the vessel:
It divides into two terminal branches: inferior gluteal and pudendal arteries.
Course of the vessel:
It passes downwords and behind the internal iliac vein /located behind and partly medialy to the artery/ along the pelvic wall and is covered medialy by the parietal peritoneum. It is main artery, which supplies all pelvic viscera, perineum and postero-anterior side of the tight.
Branches:
It gives of many branches which arise from it, as two main trunks: anterior and posterior.
Anterior trunk runs posteriorly into the grater sciatic foramen. It gives off only parietal braches.
Posterior trunk passes anteriorly to the piriform muscle and ends at the inferior part of the greater sciatic foramen.
Inferior gluteal artery arises from the anterior trunk and leaves the pelvic cavity through inferior part of the grater sciatic foramen. It supplies the gluteal region and posterior side of the tight.
Levator ani muscle
Obturator internus muscle
Prostate
Sphincter urethrae muscle
Urethra
Umbilical artery
Obturator nerve
Obturator artery
Obturator vein
Relations of the obturatory nerves and vessels on the coronal section.
Inferior vesical artery, which in female partly supply the vagina. In male it gives off the prostatic branch. Both the superior and inferior vesical arteries supply the urinary bladder.
In female: uterine artery or in male: artery of the ductus deferens.
Artery of the ductus deferens passes in the spermatic cord.
The uterine artery supplies the uterus, vagina, ovary and uterine tube. It pasess into the isthmus of the uterus, where the vaginal branch (ramus vaginalis) arises and crosses anteriorly the ureter.
Near the margin of the uterus the uterine artery ascends along the lateral margin of the uterus (there it gives off uteral branches), and next it divides into terminal branches:
Internal pudendal artery is one of two terminal branches of the internal iliac artery and supplies mostly external genital organs and perineum.
inferior rectal artery
perineal artery
artery to the bulb of vestibule or artery to the bulb of penis
urethral artery
deep artery of penis or deep artery of clitoris
dorsal artery of penis or dorsal artery of clitoris
Suprapiriform part of major sciatic foramen
Infrapiriform part of major sciatic foramen
Minor sciatic foramen
Obturator foramen
Space for vessels
Aortical bifurcation
Common iliac arteries
Sacral median artery
Iliolumbar artery
Lateral sacral arteries
Superior gluteal artery
Inferior gluteal artery
Internal pudendal artery
Branches of the internal iliac artery
The perineum
The 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.
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.
The urogenital triangle, located in front of the line, contains the genitalia and the terminal region of the urinary tract.
The anal triangle posterior to the line, contains the anal canal and anus.
Pubic symphysis
Obturator foramen
Ischiopubic rami
Urogenital triangle
Ischial tuberosity
Anal triangle behind line A-B
Sacrum and coccyx
Sacrotuberous ligament
Anal canal
The perineal region
The pelvic diaphragm
The funnel-shaped pelvic diaphragm separates the pelvic cavity (above) from the perineum.
Iliac crest
Iliacus muscle
Psoas major muscle
Acetabulum
Obturator internus muscle
Ischiorectal fossa
Anal canal
Levator ani muscle
Cavity of pelvis
Rectum
Coronal section through the posterior part of the pelvis.
The puborectalis muscle is U-shape muscular sling around the anorectal junction. Some fibers of this muscle constitute the levator prostatae and pubovaginalis.
The iliococcygeus muscle 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.
The coccygeus muscle 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
Obturator internus muscle
Tendinous arch of obturator fascia
Coccygeus muscle
Piriformis muscle
Sacrum and coccyx
Spine of ischium
Junction of rectum, and anal canal
Prostate and urethra
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 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.
The pelvic diaphragm is enclosed between two layers of the fascia:
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).
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.
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.
The posterior region of the inferior fascia of the U.G. diaphragm – perineal membrane, 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.
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). 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.
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.
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 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.
The deep perineal pouch
The deep perineal pouch or the deep perineal space, is a narrow flat space lined above and below by the superior and inferior fascial layers of the urogenital 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 urogenital 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):
The superficial transverse perineus muscle, 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.
The ischiocavernosus muscle (paired muscle), 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).
The bulbospongiosus muscle 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, 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.
The superficial perineal fascia
After reflecting the skin of the perineum, note that the superficial perineal fascia, 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 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:
Superficial abdominal fascia (fibrous layer of Scarpa),
Superficial fascia around the penis,
Darto’s fascia/ muscle lining the skin of the scrotum,
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.
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).
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
male only: contents of the scrotum
female only: greater and lesser vestibular glands
branches-internal pudendal vessels & nerves
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 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 diaphragm.
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
The inferior rectal artery branch of the internal pudendal artery
The inferior rectal nerves branch of the internal pudendal nerve
Fatty and connective tissue.
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.), 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 posterior aspect of the medial wall of ischial tuberosity, the I.P.A., the accompanying veins, and the pudendal nerves (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):
Perineal artery 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.
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 urogenital 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:
Branches of the I.P.A. given off within the deep perineal pouch:
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 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.
The dorsal artery of the penis/clitoris leaves the anterior region of the diaphragm, passes through the suspensory ligament of the penis (clitoris) to enter the dorsal aspect of the penis where it runs deep to the deep fascia of the penis (derived from fascia of bulbospongiosus muscle).
Innervation of the perineum
The perineum is supplied by the branches of one nerve – the pudendal nerve.
Superficial dorsal vein of penis/clitoris 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).
Deep dorsal vein of penis/clitoris: 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).
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.
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. The testes are also covered by visceral and parietal layers of the tunica vaginalis. The visceral layer of the tunica vaginalis covers tunica albuginea testis and epididymis.
The septa testis divides the stroma testis into lobules. The stroma testis is composed of the seminiferous tubules. The main function of the testes is production of the male gamete cells and male sex hormones called androgens.
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.
The 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. 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:
Pelvic part 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. 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.
The external spermatic fascia, which contains the dartos muscle, 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.
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 and the spongious body of 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 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. Located between the corpora cavernosa, the bulb is firmly attached to the perineal membrane. The corpus spongiosum contains the spongy urethra.
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.
The unpaired deep dorsal vein of the penis 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.
The paired superficial dorsal veins drain blood from the superficial coverings of the penis. These veins return blood into the external pudendal veins and next into the femoral veins.
The prostate 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.
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)
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).
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 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.
Neck of bladder
Median lobe of prostate
Urethra
Levator ani muscle
Prostate
Prostatic utricle
Localization of the prostatic gland on the midsagittal section.
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.
Most of lymph produced in the prostate is drained into the internal iliac and sacral lymphatic nodes.
Clinical comments: 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.
Two yellowish bulbourethral glands (Cowper’s glands) 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 about 3.5-4.0 cm in length, which pass through the urogenital diaphragm, and open into the proximal part of spongy urethra.
The paired seminal vesicles 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.
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.
The uterus is a thick (2-3 cm), pear shaped muscular female reproductive organ, measuring about 7-8 cm in length, 4-5 cm in width, which occupies the central region of the true pelvis.
The uterus is divided into four regions:
The fundus, superior, rounded part of the uterus or the part located above the entrance of the uterine tubes. The regions where the entrances of the paired uterine tubes are located are called cornua of the uterus.
The body, the region between fundus and isthmus, superior two thirds of the organ.
The isthmus, a 1 cm constricted region between the body and the cervix.
The cervix, is a 2 cm long region, half of which penetrates the posterior region of the vagina, which is called the infravaginal part. In opposition to that, the supravaginal part of cervix is defined as a region between the isthmus and posterior vaginal wall.
The cavity of the uterus is triangular in shape. The cervical canal appears as a spindle-shaped channel which narrows, anteriorly at the ostium, and posteriorly at the isthmus. The uterine ostium is a small aperture at the vaginal end of the cervical canal.
The supporting components of the uterus are as follows:
The cardinal ligament or the transverse cervical ligament is important for stabilization of the cervix in the midline position. It extends from the lateral pelvic wall to the cervix of the uterus and lateral side of the vagina.
The round ligament passes under the anterior layer of the broad ligament, from the point of the organ, which is located anteroinferiorly to the entrance of the uterine tube, to the deep inguinal ring.
The broad ligament, double layer fold of the peritoneum – extends from the lateral sides of the uterus to the floor and lateral walls of the pelvis. It contains the uterine artery, extraperitoneal tissue (parametrium), ovarian artery and vein, venous plexus. The round ligaments and uterine tubes are enclosed between layers of the broad ligament. It also gives an attachment for the ovaries as double-layer mesovarium and for the uterine tubes as mesosalpinx.
The suspensory ligaments of the ovary, fold of the peritoneum, which is prolongation of the broad ligament; it passes from the lateral end of the ovary to the lateral pelvic wall.
Anteriorly the body of uterus relates to the vesicouterine pouch of peritoneum (peritoneum is reflected from the posterior margin of the superior surface of the urinary bladder into the fundus of the uterus), which separates the bladder from the uterus. This region of the bladder also relates to the supra vaginal region of the cervix. The vaginal cervix is related to the anterior and lateral fornices of the vagina.
Posteriorly the body of uterus comes in contact with the peritoneal lining of the rectouterine pouch (of Douglas), and coils of ileum or sigmoid colon. The peritoneum, which is reflected from the fundus into the ampulla of the rectum, separates the uterus from the rectum.
Laterally, the body of uterus is related to the broad ligament and uterine vessels. The supravaginal region of the cervix contacts laterally with the descending ureters, which cross inferiorly to the uterine artery 2 cm from the cervix.
The uterus has a vesical and an intestinal surface. The relations of the uterus vary with the amount of urine in the bladder and feces in the rectum. Normally, the organ is inclined anteriorly over an empty bladder. In addition, the uterus displays two angular displacements: an angulation between its body and its cervix (anteflexion), and a larger angle (90 to 110o) with the vagina (anteversion).
the middle layer (myometrium), which is the muscular part of the uterine wall. It is a layer of smooth muscles, which normally is about 15 mm thin and increases about 100 times in length during pregnancy.
The main artery of the uterus is the uterine artery, which is a branch from the internal iliac artery. It arises as the third branch from the internal iliac artery and runs medially between layers of the broad ligament.
The uterine artery is divided into three parts:
The first portion: descends medially and anteriorly.
The second portion: passes horizontally, superiorly to the ureter, which crosses that part 2 cm laterally from the cervix of the uterus. This part gives off a branch, which supplies the cervix of the vagina.
The third portion: ascends along lateral side of the body of the uterus and gives off many branches to the uterus. At the end, it turns laterally just below the entrance of the uterine tube and runs along the uterine tube to the ovary and anastomoses (unites) with the ovarian artery.
The uterine vein accompanies adequate artery and drains to the internal iliac vein. The veins of the uterus form the uterine venous plexus, which is located on each side of the cervix, and is connected freely with the rectal, vesical and vaginal plexuses. The uterine venous plexus drains into the internal iliac vien through the uterine vein.
The lymph from the fundus is drained into the superficial inguinal lymphatic nodes (nodi lymphatici inguinales superficiales) through lymphatic vessels going with the round ligament.
Also from the fundus and superior part of the body lymph passes through lymphatic vessels within the suspensory ligament of the ovary to the lumbal lymphatic nodes.
The paired uterine tubes – Fallopian tubes (tuba uterina s. oviductus) are located on the left and right upper borders of the broad ligament and extend laterally from the cornua of the uterus. They end freely in the peritoneal cavity not so far from the ovaries. The main function of the Fallopian tube is transport of the oocytes from the ovary (the ova is directed by the ciliated epithelium of the tube to the uterine cavity) and sperm from uterus to the ampulla, where fertilization usually takes place. The portion of the broad ligament adjacent to the tube is known as the mesosalpinx.
Each (10 cm long, 1 cm width) tube is divided into four parts:
The infundibulum, resembling the mouth of a trumpet, represents the expanded lateral projection, by which the tube communicates with the peritoneal cavity. The rim of this structure has a multitude of finger-like projections, the fimbriae (20-30 of them), which overlie the ovary.
The intramural part, is shortest segment, which passes through muscular part of the uteral wall and terminates at the aperture of the uterine ostium, by which the tube connects to the cavity of uterus.
The tubal branches come from two opposite directions. The tubal branch from the uterine artery passes laterally and anastomises with another tubal branch from the ovarian artery
It receives sympathetic fibres from the coeliac plexus (upper part of the tubal plexus) and from the inferior hypogastric plexus. The uterine tube receives parasympathetic fibres from the 10th cranial nerve, and splanchnic pelvic nerves.
The ovaries (4 by 2 cm, weighing 2 – 4 g, oval in shape) are bilateral primary sex female organs, which occupy the right and left ovarian fossa of the lateral pelvic wall.
Each ovary is covered by cuboidal epithelium, which blends with the peritoneal lining of the mesovarium, however the oocytes are expelled during ovulation into the peritoneal cavity.
Each ovary has:
Anterior margin with hilum of the ovary and mesovarium (mesoovarian border of the ovary)
The suspensory ligaments of the ovary is an additional attachment, which is the lateral prolongation of the broad ligament. It provides the ovarian vessels and nerves, which enter to the hilum of the ovary through the mesovarium.
The ligament of the ovary extends from the lateral angle of the uterus to the uteral end of the ovary. It contains the ovarian branch from the uterine artery.
Relations of the ovary:
The ovary is located within the ovarian fossa of the lateral pelvic wall, which is a shallow depression within the parietal peritoneum. It is situated below the terminal line of the pelvis and in front to the sacroiliac joint.
The ovarian fossa is bounded by medial umbilcal ligament in front and by the ureter and internal iliac artery. Superiorly, the ovarian fossa is bounded by the external iliac vessels.
Sectioned ovary may be divided into:
Outer layer – cortex – contains most of the ovarian follicules.
Inner layer – medulla – composed of hormonally functional stroma.
Follicules and corpora lutea may enlarge the ovary to the diameter of 6 cm without being thought to be pathologically distended.
The ovary is supplied by the ovarian arteries, which arise from the abdominal aorta just below the origin of the renal arteries, descend to the pelvic brim, cross superiorly the external iliac arteries, next pass within the suspensory ligaments of the ovary and enter the ovary through the hilum. In addition, the ovary is supplied by the ovarian branch of the uterine artery. It runs from the uterine artery laterally within the ligament of the ovary and anastomoses with the ovarian artery.
The ovarian vein leaves the hilum and forms the pampiniform plexus near the ovary, between the layers of the broad ligament. On both sides the ovarian veins ascend from the pampiniform plexuses. The right ovarian vein enters to the IVC, but the left ovarian vein joins the left renal vein.
The vagina is female organ of copulation. It is a distensible muscular tube (7 to 9 cm in length) which extends between vestibule of the vagina and uterus.
The organ consists of two walls which are in contact except at their upper end. The posterior vaginal wall (12 cm long) is slightly longer than the anterior wall (9 cm long). The vagina descends anteroinferiorly. It pierces the urogenital diaphragm together with the sphincter uretrae muscle.
Assuming the bladder is empty, the posterior portion of the vagina receives the neck of the uterus at an angle of about 900. This angle increases as the bladder fills and elevates the fundus of the uterus. In cross sectional anatomy the lower part of the organ resembles an exaggerated letter H with a long horizontal bar limited by two short parallel lines. Only in the superior end where the cervix of the uterus enters the vagina, anterior and posterior walls are not in apposition. The vaginal recess around the cervix is called the fornix.
The relations of the vagina are as follows:
Anteriorly: bladder, terminal parts of the ureters and urethra.
Posteriorly: recto-vaginal pouch (space), rectum and anal canal.
Laterally: broad ligament and ureter, levator ani.
Inferiorly: perineal body, vestibule of the vagina.
External orifice of the vagina is sourrounded by the sphincter of the vaginal muscle.
Umbilical artery
Obturator nerve
Obturator artery
Obturator vein
Suspensory ligament of the ovary
Ovary
Obturator internus muscle
Mesometrium
Levator ani muscle
Vagina
Ureter
Mesolapinx
Meso-ovarium
Ligament of the ovary
Folds of the peritoneum around the female reproductive organs.
The labia majora are two folds of skin, which contain large amount of fatty tissue, situated on each side of the pudendal cleft. They meet posteriorly at the posterior labial commissure and anteriorly at the anterior labial commissure. They are embryologically homologous to the male scrotum.
The labia minora are delicate folds, which are located between the labia majora and they border the vestibule of the vagina. The labia minora join together superiorly to the clitoris at the prepuce of the clitoris and posteriorly in young female they meet at the frenulum of the labia minora, which is incised during labour (episiotomy).
The vestibule of the vagina is a space bounded laterally by the labia minora anteriorly by frenulum of the clitoris, posteriorly by the frenulum of the labia minora. There opens the external urethral orifice, about 2.5 cm below the clitoris and anteriorly to the vaginal orifice. The vaginal orifice is closed by the hymen during childhood and may be only a few cm in diameter in virgins.
The clitoris is 2 -3 cm long, and is an organ corresponding in female to the penis in male. It is located posteriorly to the anterior labial comissure and anteriorly to the prepuce of the clitoris.
The clitoris consists of:
root
body (composed of by two crura and two corpora cavernosa)
glans
The clitoris enlarges during tactile stimulation, but not significantly.
Each bulb of the vestibule (2.5 cm) is covered by the corresponding bulbospongiosus muscle and its fascia. The bulb of the vestibule is composed of erectile tissue and is situated on both sides of the vaginal orifice.
The posterior end of the bulb (male) is penetrated by the urethra which crosses the length of the corpus spongiosum as the spongy urethra to open at the glans penis.
The (female) urethra opens independently between vagina and clitoris without passing through erectile tissue of the corpus spongiosum.
The posterior ends of each bulb of the vestibule are in contact with a small (0.5 cm) nodular mass formed by the greater vestibular gland. The bulbs of the vestibule and the greater vestibular glands are located deep to the labia minora.
The greater vestibular gland – Bartholin’s gland is about 0.5 cm in diameter, round in shape and secretes lubricating mucus into the vestibule of the vagina.
All the veins from the vulva drain into the internal pudendal vein and next into the internal iliac vein except two external pudendal veins – they receive blood from the anterior labial veins and return blood to the femoral vein.
