Genitourinary Anatomy And Radiology

Inguinal canal

• Inguinal region: area that extends between the ASIS and pubic tubercle where structures exist and enter the abdominal cavity.
• Anterior retinaculum: made up of inguinal ligament and iliopubic tract that passes from the ASIS to pubic tubercle and acts as fibrous bands that retain the structure of the hip.
- The fibrous bands are thickened inferolateral-most portion of the external and internal layers of the anteriolateral abdominal wall.
- Subinguinal space: passage way of the hip flexor and neurovascular structure that supply the lower limb between the pubic bone and anterior retinaculum
• Inguinal ligament: dense band made up of the aponeurosis of the external oblique
- Some fibres pass posteriorly and form the lacunar ligament
- Lateral fibres continue along pectin pubis as the pectineal ligament
• Iliopubic tract: thickened inferior margin of the transversalis fascia that runs posterior and parallel to the inguinal ligament
• Inguinal canal: oblique passage of 4 cm long directed inferomedially through the inferior part of the anterolateral abdominal wall. Its formed during the descend of the testis.
- Content: spermatic cord (males) and round ligament of uterus (females), blood vessels, lymphatics and ilioginal nerves.
• Deep inguinal ring: internal entrance to the inguinal canal located superior to the middle of inguinal ligament and lateral to inferior epigastric artery.
- Formed by the evagination of the transversalis fascia through the walls and continues as the inner most covering (internal fascia) of the canal.
• Superficial inguinal ring: exit in which spermatic cord in males etc emerges from the inguinal canal. It is a split of the external oblique aponeurosis just superolateral to the pubic tubercle.
- Crura: medial and lateral margin of the superficial ring.
• Conjoint tendon: fusion of the inferior medial tendinous fibres of the internal oblique with aponeurotic fibres of the transverse abdominal muscle.
• Walls of the inguinal canal:
- Posterior wall: transversalis fascia, conjoint tendon
- Anterior wall: internal oblique and aponeurosis of the external oblique
- Roof: transversus abdominus fibers and internal oblique
- Floor: inguinal ligament and lacunar ligament
• Development of inguinal canal: in males
- Male gubernaculums: fibrous cord connecting the primordial testis to the anterolateral abdominal wall at the site of the deep inguinal ring
- A peritoneal diverticulum, process vaginalis, traverses the developing inguinal canal carrying the muscular and fascia layers of the anterolateral abdominal wall. The stalk of the vaginalis eventually fuses leaving the distal part as the tunica vaginalis ( a serous coat)
- The primordial scrotum is an outpouching of the skin and superficial fascia of the abdominal wall and testis passes through the inguinal canal into it. The ducts, vessel and nerves also descend, wrapped around by the musculofascial extension of the anterolateral abdominal wall.
• Intra-abdominal pressure effect: this causes the posterior wall of the canal against the anterior wall and strengthening the canal to prevent herniation.
• Inguinal hernia: protrusion of parietal peritoneum and viscera such as small intestine through a normal or abnormal opening from the cavity. 80-90% of abdominal hernias are inguinal
• Direct hernia: acquired hernia passes through or around the inguinal canal and parallel to spermatic cord.
- Predisposition: weakness of anterior abdominal wawll due to distended superficial ring, narrow inguinal falx etc.
- Herniation is medial to inferior epigastric vessel
• Indirect hernia: congenital hernia and traverses inguinal canal within the processus vaginalis (spermatic cord)
- Predisposition: patency of processus vaginalis in younger persons
- Herniation is lateral to inferior epigastric vessel

Kidney, ureter, bladder and posterior abdominal wall

• Location of kidneys: lies retroperitoneally on the posterior abdominal wall in the paravertebral gutter at level T12-L3.
• Features of kidney:
- Size: 10 cm by 5 cm by 2.5 cm
- Associations: superiorly with the diaphragm, posteriorly with the psoas major, quadratus lumborum, transverses abdominis (medial to lateral)
- Surfaces: anterior and posterior
- Coverings: fibrous capsule with fat, fascia
• Neurovascular associations: subcostal, iliogastric and ilioinguinal nerve passes diagonally across the surface of the kidney.
• Distinction between kidneys: right kidney is usually slightly inferior to the left kidney, owing to its relationship with the liver
- Left kidney is related anteriorly to stomach, spleen, pancreas, descending colon and small intestine while the right kidney is related to liver, duodenum, ascending colon
- Right renal artery is longer than left renal artery (aorta lies on the left side)
- Left renal vein is longer than right renal vein
• Nerve innervations of kidney: renal nerve plexus consisting of sympathetic and parasympathetic fibers.
• Renal pelvis: flattened funnel shaped expansion of the superior end of the ureter
- Receives two or three major calices, whom which receives two or three manor calices (receives renal papilla)
• Ureter: muscular ducts with narrow lumen (lined by transitional cells) that carry urine from the kidney to the urinary bladder.
- These run inferiorly from the apex of the renal pelvis, courses laterally to psoas major, passes over the pelvic brim at the bifurcation of the common iliac artery, crosses anteriorly to the sacroiliac joint and then to the lateral wall of the pelvis and enter the urinary bladder.
- Length: 25 cm with straight half lying in the abdomen and the curved half in the pelvis
- Relations of ureter: adhere closely to parietal peritoneum and also psoas major and transverse processes of lumbar vertebrae, common iliac artery, pelvic inlet and uterine artery
• Constriction of ureters:
- Junction of ureters and renal pelvic (pelviureteric junction)
- Ureters cross the brim of the pelvic inlet
- Terminal passage through the wall of the urinary bladder (intramural)
• Arterial supply of ureter: abdominal portion of ureter is supplied by renal arteries, with less constant branches arising from gonadal arteries, abdominal aorta and common iliac arteries
- Course: approach ureter medially and dividing to ascending and descending branches.
- Surgical significance: as a result, surgery of the posterior abdominal region may disrupt the delicate blood supply of the ureter and cause ischemia
• Nerve innervations of kidney: abdominal part of the ureter derived from the renal, abdominal aortic, and superior hypogastric plexuses. Visceral afferent fibers conveying pain sensation follow sympathetic fibers to cord segments T11-L2.
- Hence ureteric pain is usually referred to the ipsilateral lower quadrant of the anterior abdominal wall to groin
• Bladder: a distensible muscular sac that acts as a temporary reservoir for urine and varies in size, shape, position and relations according to its content and state.
- Shape: pyramidal when empty and round when full
- Location: lesser pelvis, when empty, is situated superior and posterior to the pubic bones (superior surface at level of superior margin of pubic bone)
- Surface: superior (covered by peritoneum), posterior and 2 inferiolateral
- Relations: apex of bladder points toward superior edge of pubic symphysis. Anteriorly with retropubic space. Posteriorly with vas deferens, seminal vesicle, rectum. Superiorly with perineum and intestine. Inferolaterally with pelvic diaphragm
• Ligaments of the bladder: bladder is relatively free within the extraperitoneal subcutaneous fatty tissue except for its neck which is held firms by lateral ligaments of the of bladder and tendinous arch of the pelvic fascia
- Urachus (medial umbilical ligament)
- Puboprostatic ligament in males
- Pubovesical ligaments in females
• Parts of the bladder:
- Fundus: opposite to apex
- Body: major portion of bladder between apex and fundus
- Neck: junction of fundus and inferolateral surfaces and is continuous with the prostatic urethra
- Internal urethral sphincter: involuntary muscular fibers located at the neck of the bladder that prevents ejaculation of semen into the bladder.
- Ureteric orifice: opening of ureter into bladder. These are encircled by detrusor muscles that tighten when bladder contracts to prevent reflux.
- Internal urethral orifice: inner opening of bladder into the urethra
- Trigone of bladder: the triangular area formed by the ureteric and internal urethral orifice
- Interureteric ridge: muscular connection between the ureteric orifices
- Uvula of bladder: slight elevation of the trigone
• Arterial supply of bladder: branches of the internal iliac arteries
- Superior vesical arteries supply anterosuperior parts
- In males the inferior vescial arteries supply fundus and neck while in females the vagina arteries supply those parts.
• Nerve innervation of bladder:
- Sympathetic fibers from lower thoracic and upper lumbar segments. These are also motor neurons that contract the internal urethral sphincter (urine retention)
- Parasympathetic fibers are conveyed by pelvic splanchnic nerves from S2-S4 segments. These acts as motor to detrusor muscles and inhibitory to the internal urethral sphincter (urination).

Female Internal Genitalia

• Ovary: almond shaped female gonads and endocrine gland.
- Location: near the attachment of the broad ligament on lateral wall of pelvis
- Attachment: medially by the ligament of ovary within mesovarium and laterally by the suspensory ligaments form the pelvic walls.
• Suspensory ligament: vessels, lymphatics and nerves pass to and from the superolateral aspect of the ovary within the suspensory ligament of the ovary
• Communication with the peritoneal cavity: the ovary is suspended within the peritoneal cavity. When the oocyte is expelled, it travels from inside the peritoneum into the fimbriae of the infundibulum, passing through the ampulla to the uterus, where it forms immediate connection to the outside of the body
• Uterine tube: the fallopian tube that conducts the oocytes and directs it into the uterine cavity. The tube extends posterolaterally to the lateral pelvic walls and arch anterior and superior to the ovaries.
- Length: 10cms
- Locations: lie in the mesosalpinx (small mesentery) in the free edges of the broad ligaments
• Parts of the uterine tube:
- Infundibulum: funnel shaped distal end of the tube that opens into the peritoneal cavity through fimbriated opening. The fimbria spreads over the medial surface of the ovary.
- Ampulla: widest and longest part of the tube where fertilization usually occurs
- Isthmus: thick-walled part of the tube that enters the uterine horn
- Uterine tube: short intramural segment of the tube that passes through the wall of the uterus
• Clinical significance:
- Tubal ligation: permanent form of female sterilization in which female uterine tube are severed and sealed to prevent fertilization
- Salpingitis: infection and inflammation of the fallopian tube
• Arterial supply of ovaries and uterine tube:
- ovarian arteries that arise from the abdominal aorta. The artery descend along the posterior abdominal wall and cross the external iliac vessels and enter the suspensory ligament
- ascending branches of the uterine arteries
• Venous drainage of ovaries and uterine tube: tubal vein drain into uterine venous plexus forms single uterine veins
- Left ovarian vein drains into the left renal vein
- Right ovarian vein drains into the IVC
• Uterus: thick walled, peared shaped muscular organs in which the fetus develop. The uterus is adapted for growth of the fetus and provides power of expulsion during birth.
- Location: lies in the lesser pelvis on the urinary bladder and anterior to the rectum. However the position does change with degree of fullness of bladder and rectum.
• Orientation of the uterus:
- Anteflexed: bent anteriorly relative to the cervix
- Anteverted: tipped anterosuperiorly relative to the axis of the vagina
• Parts of the uterus:
- Body of the uterus: superior two thirds of the organs
- Fundus of the uterus: rounded roof of the uterus that lies above the uterine tube orifices
- Cervix of the uterus: cylindrical narrow inferior third of the uterus
• Wall of the body of uterus:
- Endometrium: inner mucous coat, involved in the menstrual cycle
- Myometrium: middle coat of smooth muscle capable of great distension during pregnancy.
- Perimetrium: serosa or outer serous coat consisting of peritoneum supported by thin layer of connective tissue.
• Broad ligament: a double layer of peritoneum that extends from the side of the uterus to the lateral wall. Laterally the peritoneum of the broad ligament is prolonged superiorly over the vessels as the suspensory ligament of the ovary.
- Largest portion of the broad ligament is inferior to the mesosalpinx and mesovarium that serve the mesentery for the uterus itself.
• Support of uterus: dynamic support of uterus is provided by the pelvic diaphragm while passive support is by its position (the cervix is least mobile due to condensed endopelvic fascia)
- Ligament of ovary: attaches posteroinferior to the uterotubal junction
- Round ligament: attach anteroinferior to the uterotubal junction
- Cardinal ligaments: extend from cervix and lateral part of the fornix of vagina to lateral walls of pelvis (most important lateral support)
- Uterosacral ligament: pass superiorly and slightly posteriorly from the sides of the cervix to the middle of the sacrum (palpable).
• Relations of the uterus: peritoneum covers the uterus anteriorly and reflected on to the bladder while posteriorly on to the rectum.
- Anterior: vesicouterine pouch, bladder
- Posteriorly: rectouterine pouch (douglas), rectum
- Laterally: broad ligament. The uterine arteries passes above the ureter approximately 2cm lateral to the upper cervix (important as during removal of uterus, ureter maybe affected)
• Arterial supply of the uterus:
- Uterine artery: a branch of the internal iliac artery
- Ovarian artery: a branch of the aorta
• Venous and lymphatic drainage:
- Vein drainage is through the uterine venous plexus on each side of the cervix that pass into the internal iliac veins
- Lumbar lymph nodes: drains fundus and superior uterine body
- Superficial inguinal nodes: entrance of uterine tube
- Iliac inguinal nodes: most of the uterine body and cervix
• Vagina: musculomembranous tube (7-9 cm long) extending from cervix to vestibule.
- Function: canal of menstrual fluid, pelvic canal, receives the penis, communicate with cervical canal.
- Relations: anteriorly with bladder and urethra and posteriorly with Douglas pouch, rectum and perineal body, laterally with levator ani muscles, ureters and visceral pelvic fascia
• Arterial supply of vagina: uterine arteries superiorly and vaginal and internal pudendal arteries inferiorly
• Venous and lymphatic drainage of vagina:
- Vaginal veins form vaginal venous plexus along the side and linked to uterine venous plexus
- Lymph: iliac lymph nodes superiorly, internal iliac in middle and sacral and common iliac nodes inferiorly
• Innervation of vagina and uterus:
- Inferiorly somatic from deep perineal nerve (branch from pudendal)
- Superiorly autonomic innervation by the uterovaginal nerve plexus

Radiology of Male and Female Pelvic Organs

• Orientation of pelvis in standing position:
- Anterior superior iliac spine and pubic tubercle perpendicular to floor
- Urogenital triangle horizontal
• Ultrasound: common modality used to image the uterus, fallopian tube, ovaries, pelvic ligament.
- Full bladder allows images of the uterus and ovaries from abdomen. Ultrasound can not pass through air so bowel presents a problem. Full bladder is a method of displacing bowel
- For greater detail, trans-vaginal ultrasound is performed on an empty bladder
- Unless there is ascites present, broad ligament is rarely seen on CT or ultrasound
- During pregnancy, the uterus rises from the episternum
• Bimanual examination: hand in uterus and abdomen to examine size of uterus sandwiched in between
• Clinical problems of peritoneal: ovary is released intra-abdominally before being swept by the fimibrae into the fallopian tube. Thus as a result, ectopic pregnancy and blocked fallopian tubes and intra-abdominal pregnancy can occur.
• Clinical importance of uterus:
- 10-20% of uterus is retroverted making it more difficult to examine with ultrasound. Transvaginal scan is required
- Walls of the uterus always touching each forming a tiny slit. Endomestrium shows up as a white layer with the ultrasound (white halo) as the months pass.
• Clinical relations of pouch of douglas:
- Fluid from ovulation accumulate
- Pelvic inflammatory disease has oozy transudation in the pouch
• Ultrasound of male pelvis: imaging of prostate gland and testis
- Examine benign prostatic hyperplasia and prostatism
- Pelvic trauma may damage urinary bladder and urethra
- Scrotal imaging for testicular mass, testicular pain and differentiating testicular torsion and infection.
• Coloured Doppler: assess for blood flow and confirm ischaemia such as that with testicular torsion
• Epididymitis: caused by chlamydia and can get mumps or virus. Ultrasound shows up as a “ring of fire”
• Bladder wall tumour: ultra sound first. Bladder wall thicker in one area with mushroom growth from the sides. There may be blood in urine
• Syphilis and gonorrhoea: urethra stricture investigated using dye.
• Benign prostate hyperplasia: unable to pass urine as urethra is occluded. However imaging does not show narrowing of prostatic urethra as it passes through the prostate.
- Transurethral resection of prostate: removal of tissue by sharp dissection to relieve symptoms
• Clinical complications of testicle: ultrasound is a non-invasive way of imaging
- Testis in pelvis undescended so grows in a flattened manner. Associated with high risk of cancer and infertility

Radiology of Renal Tract

• Kidney obstruction: iodine absorb X-ray and shows slow excretion and dilated kidney
• Kidney stone: dye is blocked and not passing the tubule
• Renal tumour: can extend into the vein
• Pelviureteric junction obstruction: blockage of the area where ureter leaves the kidney in the renal pelvis.
- Examined with an intravenous pyelogram into which dye is injected into blood stream. X-ray will show the shape of the kidney, ureter to confirm blockage
• Vesicoureteric junction obstruction: blockage of the junction between ureter and bladder causes squeeze the urine back up (vesico-reteric reflux) causing a condition called megaureter. This is shown as large white lines of ureter from the bladder on x-ray with dye.
• Posterior urethral valves: abnormalities with the valves of the urethra that causes reverse flow of urine leading to massively dilated kidney (huge white mass)
• Renal colic: kidney stones. Presentation of loin to groin referred pain. On CT-scan shows up as white dots. If located more posterior indicated blocked ureter

Male Internal Genitalia

• Prostate: inverted cone shaped accessory organ of the male reproductive system made up of 2/3rd glandular and 1/3rd fibromuscular stroma.
- Fibrous capsule of prostate: dense and contains neurovascular structures of veins and nerves lined by a visceral layer of pelvic fascia
- Base: closely related to the neck of the bladder
- Apex: lies on the urogenital diaphragm
- Anterior surface: forms a part of the urethral sphincter separated from the pubic symphysis by retroperitoneal fat.
- Posterior surface: related to the ampulla of the rectum
- Inferolteral surface: related to the levator ani
• Anatomical lobes of prostate:
- Anterior: anterior to urethra and contains little glandular tissue
- Inferoposterior lobe: posterior to the urethra and inferior to the ejaculatory duct
- Lateral lobe: lateral to the urethra form the major part of the prostate
- Middle lobe: lies between the urethra and the ejaculator duct. Outgrowth forms partially a uvula that project into the internal urethral orifice.
• Relations of the prostate:
- Bladder superiorly
- Urogenital diaphragm inferiorly
- Retropubic space anteriorly
- Rectum posteriorly
- Pelvic diaphragm laterally
• Zones: central zone is middle lobe and peripheral zone is the remaining lobes
• Arterial supply of the prostate: prostatc arteries from branches of the internal iliac artery and the inferior vesical arteries
• Venous drainage: rich prostatic venous plexus drain into the internal iliac vein and internal vertebral veins (veins are thin walled and extensive)
• Lymphatics: internal iliac and sacral lymph nodes
• Prostatic urethra: part of the urethra that traverses the prostate.
• Urethral crest: median ridge between the bilateral grooves of prostatic sinus in the prostatic urethra
• Seminal colliculus: rounded eminence in the middle of the urethral crest with a slit like orifice that opens into the prostatic utricle. Also known as verumontanum
• Prostatic utricle: vestigial remnant of the embryonic uterovaginal canal. The ejaculatory ducts usually opens into the prostatic urethra via small opening located adjacent or within the orifice of the prostatic utricle.
• Prostatic ducts: ducts that open into grooves of the prostatic sinus on the posterior wall of the prostatic urethra.
• Bulbourethral gland: pea sized glands that lie posterolateral to the intermediate part of the urethra within the external urethral sphincter. Ducts of the gland pass into the proximal part of the spongy urethra in the bulb of penis and secretion is used in sexual arousal.
• Ductus deferens: continuations of the duct of the epididymis at the inferior pole of the testis. The duct has relative thick muscular walls and minute lumen.
• Path of the ductus deferens:
- Ascends posterior to the testis
- Penetrates the anterior abdominal wall via the inguinal canal
- Crosses the external iliac vessels and enters the pelvis
- Pass along the lateral wall of the pelvis, lies external to the parietal peritoneum (maintains direct contact)
- Ends by joining the ducts of the seminal glands as the ejaculatory duct medially
• Features of the ductus deferens:
- Ductus crosses superior to the ureter near the posterolateral angel of the bladder
- Forms the ampulla before termination
• Arterial supply of ductus deferens: Artery of the ductus deferens from the superior vesical artery. These anastomoses with the testicular artery posterior to the testis.
• Seminal vesicle: thin walled coiled tubular glands and that ends by joining the vas deferens to form the ejaculatory duct.
- Location: between the fundus of the bladder and the rectum above the prostate
- Function: secrete a thick alkaline fluid with fructose and coagulating agents that adds to prostatic secretion to form the seminal fluid (does not store sperm)
• Ejaculatory duct: slender ducts that arise by the union of vas deferens and seminal vesicles. These open on the seminal colliculus or within the prostatic utricles.
- Length: 2.5 cm long
- Course: arise near the neck of the bladder and pass anteroinferiorly through the posterior part of the prostate.

External Genitalia

• Penis: the male copulatory organ consisting of a root, body and glans.
• Root of the penis: the beginning of the penis made from two crura and a bulb
- Location: the superficial perineal pouch between the perineal membrane superiorly and deep perineal fascia inferiorly.
- crus: continuations of the corpus cavernosa muscles that diverge into two tapering process and attaches to the ischiopubic ramus anterior to the ischial tuberosity
- bulb: expanded posterior portion of the corpus spongiosum lying between the two crura and attached to the perineal membrane
- Ischiocavernosus: muscles arising from behind the crus on the inner surface of the ischium and functions to compress the crus of penis to retain blood and help stabilize erect penis
- Bulbospongiosus: in male surround lateral aspect of the bulb of penis and proximal part of the body. Function is compression of bulb of penis to expel semen/uirine and assists erection
• Body of the penis: free long shaft suspended from the pubic symphysis made from three cylindrical bodies of erectile cavernous tissue
- Corpora cavernosa: dorsal paired erectile tissue that insert distally into the glans of the penis
- Corpus spongiosum: single ventral erectile mass that expands distally to form the glan of the penis and is traversed by penile urethra
• Glan of penis: the head of the penis
• Coverings: skin, loose connective tissue and thick tubular deep fascia
- Skin: darkly pigmented relative to adjacent skin
- Tunica albuginea: outer fibrous covering or capsule of the cavernous body
- Deep fascia (buck fascia): continuation of the deep perineal fascia that forms a strong membranous covering for the corpora cavernous and corpus spongiosum.
• Arterial supply of the penis: branches of the internal pudendal artery
- Deep artery of the penis supplies the corpora cavernosa (responsible for erection)
- Artery of bulb supplies the corpus spongiosum
- Dorsal arteries of penis
• Venous drainage: venous plexus that joins the deep dorsal vein of the penis in the deep fascia
• Nerves: mainly S2-S4 pudendal nerves. Sympathetic and sensory is by the dorsal nerve of penis which is a termination branch of pudendal nerve.
• Male urethra: around 20 cm in length extending from the internal to external urethral orifices. At the end in the glan of the penis, the urethra expand out into a navicular fossa
- Prostatic urethra: widest and dilatable section that traverses prostate (3 cm)
- Membranous urethra: shortest and least dilatable section that traverses UGD (1 cm)
- Penile urethra: longest urethra hat traverses the corpus spongiosum (16 cm). The external orifice is the narrowest part of the male urethra.
• Angulations of the urethra: clinically important in catheterization as rupture can causes bleeding into the superficial perineal pouch.
- Penile part: around middle of penis
- Bulba part: located at the bulbourethral gland
• Erection: rigidity of the penis due to engorgement of the erectile tissue with blood
- Parasympathetic stimulation of S2-S4 nerve causes arterial vasodilatation and relaxation of the smooth muscles (release of NO, increase in cGMP, vasodilation)
- Blood is allowed to flow into the cavernous spaces
- Reduction in venous return occurs by the skeletal muscles ischiocavernosus and bulbospongiosus that is stimulated by the S2-S4 pudendal nerves
• Emission: delivery of semen into prostatic urethra from the vas and ejaculatory duct.
- This is a sympathetic response by L1 and L2 nerve
• Ejaculation: expulsion of semen through the external urethral orifice. This is produced by
- Clonic contracts of bulbospongiosus and ischiocavernosus (somatic)
- Contractions of internal urethral muscles (parasympathetic)
- Closure of internal vesicle sphincter at the neck of bladder (sympathetic)
• Resolution: flaccid state subsiding from erection due to:
- Sympathetic stimulation which causes constriction of smooth muscles of arteries of the cavernosa
- Increased in venous return by relaxation of the bulbospongiosus and ischiocavernosus.
• Clinical correlations:
- Injuries to male urethra: fibrosis of the deep fascia
- Hypospadia: opening of the external part of the urethra on ventral side
- Phimosis: tight foreskin
• Female external genitalia: serves as a sensory an erectile tissue for sexual arousal, direct flow of urine and prevent entry of foreign material into UG tract
• Mons pubis: rounded fatty eminence anterior to the pubic symphysis covered with coarse pubic hairs after puberty. Forms the boundary of pudendal cleft and posteriorly the folds unite to form posterior commissure
• Pudendal cleft: central depression of the external genitalia (narrow slit when legs adducted)
• Labia majora: prominent folds of skin that indirectly provide protection for urethral and vaginal orifices.
• Vestibule: space between the labia minora in which the urethra and vagina and ducts of vestibular glands open.
• Labia minora: rounded folds of fat-free hairless, pink skin that immediately surround the vestibule.
- Anteriorly the minora unite to form the frenulum and prepuce of the clitoris
- Posteriorly the minora unite to form the fourchette (posterior commissure)
• Clitoris: erectile organs of sexual arousal consisting of root, body (has crura and corpora cavernosa) and glans.
• Bulb of vestibule: paired masses of elongated erectile tissue along the sides of the vaginal orifice
• Vestibular glands (Bartholin’s gland): located on each side of the vestibule and ducts open on each side of the vaginal orifice and secrete mucus for sexual arousal.
• Muscles:
- Ischiocavernosa: originates from ischiopubic ramus and embraces the clitoris inserting to the crus and perineal membrane. Helps to maintain erection of clitoris by compressing outflow of veins.
- Bulbospongiosus: arise from the perineal body and passes on each side of lower vagina enclosing bulb and inserts into fascia of corpora cavernosa of clitoris. Acts as a sphincter of vagina and assists in erection of clitoris.

Perineum and urogenital triangle

• Perineum: region that lies inferior to pelvic diaphragm and covered by an arbetween upper medial surfaces of the two thighs.
- When the two legs are adducted forms the diamond shape
- Clinically the perineum is defined as area between the external genitalia to the anal orifice
• Boundary of the perineum:
- Anteriorly the pubic symphysis
- Anterolaterally the ischiopubic rami
- Posterolaterally the sacrotuberous ligament
- Posteriorly the coccyx
• Subdivision of perineum: transverse line joining the anterior ends of the ischial tuberosities divides the diamond-shaped perineum into two triangles. Anteriorly the urogenital triangle and posteriorly the anal triangle
• Urogenital triangle: closed by a thin sheet of tough deep fascia (perineal membrane) that stretches between the pubic. The membrane is pierced by the urethra in both sexes and by vagina of the female.
- Content of the UG triangle: UG diaphragm, root of penis/clitoris, external genitalia and urethra and vessels and nerves
• Perineal body: the central tendon of the perineum containing collagenous and elastic fibers and both skeletal and smooth muscles.
- It is the site of convergence for bulbospongiosus, external anal sphincter, superficial and deep transverse perineal muscles
- Important in females to maintain integrity of pelvic diaphragm and adjacent viscera
• Perineal fascia:
- Superficial perineal fascia: consists of the fatty layer (female is labia majora, males is dartos muscles and scrotum) and membrane layer (Colles fascia). The membranous layer does not extend into anal triangle
- Perineal membrane
- Superior fascia of UGD
• Superficial perineal pouch: potential space between the perineal membrane and superficial fascia, bounded laterally by the ischiopubic rami
- Content in male: root of penis and associated muscles, proximal spongy urethra, superficial transverse perineal muscles, deep branches of internal pudendal vessel and nerves
- Content in female: clitoris and associated muscles, bulbs of vestibule, greater vestibule glands, superficial transverse perinea muscles, deep branches of internal pudendal vessel and nerves
- Extravasations of the urogenital organs causes blood to accumulate in this space
• Deep perineal pouch: potential space bounded inferiorly by the perineal membrane and superiorly by the superior UG fascia.
- Content: deep transverse perineal muscles, urethra, vessels and nerves, urethral gland in male and vagina in female.
• Artery of the perineum: branches of internal pudendal artery
• Nerve of perineum: branches of the pudendal nerve (S2-S4)
• Pelvic diaphragm: a layer of thin muscles (levator ani) that covers the superior portion of the UG diaphragm.
- Genital hiatus: passage in the pelvic diaphragm that allows the vagina and urethra to pass through. Covered by the perineal membrane

Testis, Epididymis, Spermatic Cord

• Spermatic cord: suspensory structure of the testis
- Passes from deep inguinal ring to the scrotum at the posterior border of the testis
- Internal spermatic fascia: derived from the transversalis fascia
- Cremasteric fascia: derived from the fascia of both the superficial and deep surfaces of internal oblique muscle
- External spermatic fascia: derived from the external oblique aponeurosis and its investing fascia
• Cremaster muscle: formed by the lowermost internal oblique arising from the inguinal ligament. It reflexively draws the testis superiorly in response to cold.
- Innervated by the genital branch of the genitofemoral nerve
• Constituents of the spermatic cord:
- Ductus deferens
- Testicular artery
- Artery of ductus deferens
- Cremasteric artery
- Pampiniform venous plexus
- Sympathetic nerve fibres
- Genital branch of the genitofemoral nerve
- lymphatics vessels
- Vestige of processus vaginalis
• Scrotum: cutaneous sac consisting of heavily pigmented skin and dartos fascia.
- Dartos fascia: fat free fascia layers consisting of smooth muscle fibers. Contraction of dartos muscle causes the scrotum to wrinkle when cold.
- Dartos fascia is continuous anteriorly with the Scarpa fascia of the abdomen and posteriorly with the Colles fascia of the perinuem
• Anatomy of scrotum:
- Septum of scrotum: continuation of the dartos fascia that divide the scrotum internally into right and left compartments.
- Scrotal raphe: cutaneous ridge marking external the line of fusion of labioscrotal swelling.
• Arterial supply of scrotum: posterior scrotal branch (internal pudendal), anterior scrotal branch (femoral artery) and cremasteric artery
• Lymphatics: drain into the superficial inguinal lymph nodes
• Nerve innervation of scrotum:
- Genital branch of genitofemoral nerve
- Anterior scrotal nerves (ilioinguinal)
- Posterior scrotal nerve (pudendal)
- Perineal branch (posterior femoral cutaneous)
• Tests: male gonads suspended in the scrotum by the spermatic cord
- Tunica albuginea: tough fibrous outer surface of the testis into fibrous septa arise and extend inwards between lobules of seminiferous tubules.
- Seminiferous tubules: sperm production ducts. These are joined by straight tubules to rete testis
- Tunica vaginalis: closed peritoneal sac partially surrounding the testis. The visceral layer covers the testis and partial layer is adjacent to the internal spermatic fascia and extends upwards a short distance into the spermatic cord.
• Arterial supply of testis: testicular arteries that arise from the abdominal aorta. These passes through the inguinal canal.
• Venous drainage of testis: pampiniform venous plexus lying anterior to the vas deferens drains the testes. It is also part of the thermoregulatory system that keeps testes at a constant temperature.
- Veins of the network converge superiorly forming right testicular vein that goes to IVC and left testicular vein that enters the left renal vein
• Lymphatics: drainage follows testicular artery to right and left and preaortic lymph nodes
• Epidiymis: elongated structre on the posterior surface of the testis. It is formed by minute convolutions of the duct of the epididymis, so tightly compacted that they appear solid.
- Head: superior expanded part of the lobules formed by coil ends of efferent ductules
- Body: consists of convoluted duct of epididymis
- Tail: continuous with ductus deferens
• Crytotorchidism: congenital or acquired absence of testicles
- Undescended testis: 90% palpable in inguinal region
- Impalpable testis: located in abdomen, inguinal canal or absent
- Ectopic testis: descended testis but not located in the scrotum. Possible locations are femoral, perineal, pubopenile, and crossed.
- Pathology: testis require cooler temperature of scrotum for normal development
- Treatment: orchidectomy or orchidopexy (bringing the testis down to scrotum and suturing).
• Consequences of crytotorchism:
- failure of germ cell maturation and oligospermia
- 5-10 folds risk of testicular tumour
- Atrophic testis
- Prone to trauma
- Prone to torsion
- Cosmetic
• Hydrocele: collection of flid in the tunica vaginalis due to a patent processus vaginalis in children or misbalance in fluid production and absorption in adults.
- Treatment: ligate the patent processsus
- Clinical signs: feel of normal cord above the hydrocele, transilluminate with torch and not reducible (not hernia)
• Acute scrotum:
- Torsion of the testis: generally in adolescent with the testis twisting inside the tunica vaginalis due to abnormal attachment o the vaginalis
- Torsion of an appendage testis
- Epididymitis
- Idiopathic scrotal oedema
• Varicocele: enlargement of veins in the pampiniform plexus
- In young boy could be due to obstruction of testicular vein by a renal tumour
- Aetiology: increased pressure in testicular vein (commonly left sided)
- Pathology: warms testis (by disrupting the countercurrent heat exchange) and interfere with spermatogenesis
- Clinical presentation: infertility, dragging pain, feels like a bag of worms
- Treatment: radiology, laparoscopic high ligation or ligation of veins via a groin approach.

Pelvic diaphragm, Pelvic Nerves and Vessels

• Pelvic diaphragm: a broad thin muscular sheet made up of the coccygeus and levator ani muscles along with the superior and inferior fascias.
- Shape: funnel or gutter shaped
- Levator ani: puborectalis, pubococcygeus, iliococygeus
- Nerve innervation: S4 and pudendal nerve
• Coccyugeus: originated from the ischial spine and inserts into the lateral lower parts of the sacrum
• Levator ani: originated across the bony connection between pubic bone and ischial spine and inserts into the coccyx, anococcygeal raphe.
- Muscle fiber interdigitates in the middle along the anococcygeal ligment
• Function of pelvic diaphragm:
- Supports and maintains pelvic viscera in position
- Resistance the increase in intraabdominal pressure
- Helps in sphincteric mechanism
- Allows passage of urethra and vagina through hits genital hiatus
• Pelvic arteries:
- Bifurcation of the common iliac occurs at L4
• Internal iliac artery: bifurcation occurs at S1
- Branches of posterior division: superior gluteal, lateral sacral, iliolumbar
- Branches of anterior division: inferior gluteal, internal pudendal and obturator
• Pelvic nerves:
- Somatic nerves: lumbar is obturator L4-5 while sacral nerve is S1-S5
- Sympathetic nerves: sympathetic trunk and plexus (T11-L2)
- Parasympathetic nerves: S2-S4 and pelvic splanchnic nerve
• Weakness of pelvic visera: herniation of uterus into vagina and prolapse of bladder
• Perineal tear: laceration during birth involves
- vaginal mucosa
- skin over ischioanal fosaa
- superficial transversal perineal muscle
- May lead to dyspareania (pain during intercourse)

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