Which arteries supply the anal canal inferior to the pectinate line, surrounding muscles, and peri-anal skin?
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Inferior rectal arteries.
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Which arteries supply the anal canal inferior to the pectinate line, surrounding muscles, and peri-anal skin?
Inferior rectal arteries.
What is the mediastinum of the testis?
A thickened ridge on the internal posterior aspect of the tunica albuginea from which septa extend inward between lobules of seminiferous tubules.
What forms the epididymis?
Convolutions of the epididymal ducts.
What are the posterior attachments of the deep membranous layer?
Posterior margin of perineal membrane and perineal body.
Where do the inferior cluneal nerves arise and emerge from?
Deep to and from the inferior border of the gluteus maximus.
Which veins drain into the internal iliac veins?
Middle rectal veins.
Through which structure does the genitofemoral nerve's genital branch emerge?
Through or near the superficial inguinal ring.
What shape are the ischio-anal fossae?
Large fascia-lined wedge-shaped spaces.
Which arteries supply the testes?
The testicular arteries from the abdominal aorta and the artery of the ductus deferens.
What is the course of the inferior anal (rectal) nerve?
Passes medially from the area of the ischial spine and traverses the ischio-anal fat body.
What are the lateral boundaries of the ischio-anal fossae?
Ischium and the inferior part of obturator internus.
What are the medial boundaries of the ischio-anal fossae?
External anal sphincter and the medial part of levator ani.
What is the pudendal cleft?
The space between the labia majora when the thighs are adducted, containing the labia minora and vestibule.
To what is the deep perineal fascia fused anteriorly in males?
Suspensory ligament of penis.
What is the perineum?
The diamond-shaped shallow compartment bounded by the pelvic outlet.
What is the pathway of sperm from the seminiferous tubules to the spongy urethra?
Seminiferous tubules → straight tubules → rete testis → efferent ductules → head of epididymis → body of epididymis → tail of epididymis → ductus deferens → ejaculatory duct → prostatic urethra → membranous urethra → bulbous urethra (in bulb of penis) → spongy urethra.
What forms the inferior boundary of the deep perineal pouch?
The perineal membrane.
What forms the lateral boundary of the deep perineal pouch?
The inferior portion of the obturator fascia.
What are the common contents of the deep perineal pouch in both sexes?
Part of the external urethral sphincter and anterior extensions of ischio-anal fat pads.
What are the contents of the deep perineal pouch in females?
Proximal part of the urethra, vaginal hiatus, deep transverse perineal muscles, sphincter urethrovaginalis, compressor urethrae, external urethral sphincter, and dorsal neurovasculature to the clitoris.
Which muscles are found in the deep perineal pouch of females?
Deep transverse perineal muscles, sphincter urethrovaginalis, compressor urethrae, and external urethral sphincter.
What is the function of the bulbourethral glands in males?
They secrete a pre-ejaculate fluid that lubricates the urethra.
Where does the left testicular vein drain?
Into the left renal vein.
Where do the lymphatics of the testes drain?
Into the right and left lumbar nodes and preaortic nodes.
Where do the crura of the clitoris attach?
To the inferior pubic rami and the perineal membrane deep to the labia.
Where does the intermediate part of the male urethra begin and end?
It begins at the apex of the prostate and ends as the urethra enters the bulb of the penis.
What are the two dilated areas of the spongy urethra?
The intrabulbar fossa in the bulb of the penis and the navicular fossa in the glans of the penis.
What is the origin of the bulbospongiosus muscle in males?
Median raphe on ventral surface of bulb of penis, perineal body.
What are the contents of the superficial perineal pouch in females?
Clitoris and ischiocavernosus, bulbs of vestibule and bulbospongiosus, greater vestibular glands, superficial transverse perineal muscles, deep perineal branch of internal pudendal vessels, and pudendal nerves.
What are the three cylindrical cavernous bodies of erectile tissue in the penis?
Paired corpora cavernosa dorsally and a single corpus spongiosum ventrally.
How is the perineum divided?
By a transverse line joining the anterior ends of the ischial tuberosities into the anal triangle posteriorly and the urogenital triangle anteriorly.
Which artery forms anastomoses with the superior and inferior rectal arteries?
Middle rectal artery.
Which veins are part of the caval system?
Inferior rectal veins.
What are the lateral attachments of the deep membranous layer?
Fascia lata of superomedial thigh.
What are the components of the vulva?
Mons pubis, labia majora, labia minora, clitoris, bulbs of the vestibule, greater and lesser vestibular glands.
What arteries supply blood to the epididymis?
Testicular artery and artery of the vas deferens.
Where do the posterior labial/scrotal nerves arise and what is their course?
Arise in the anterior (terminal) end of the pudendal canal and pass medially and superficially.
What neurovascular structures are found in the deep perineal pouch of females?
Dorsal neurovasculature to the clitoris.
With what is the deep perineal fascia continuous?
Deep fascia covering external oblique muscle.
To what is the deep perineal fascia fused anteriorly in females?
Suspensory ligament of the clitoris.
What structures are contained within the pudendal canal?
The internal pudendal artery and vein, the pudendal nerve, and the nerve to obturator internus.
Which arteries supply the male urethra?
The dorsal artery of the penis.
What is the insertion of the bulbospongiosus muscle in males?
Perineal membrane, dorsal aspect of corpus spongiosum, corpora cavernosa, fascia of bulb of penis.
Which structures are supplied by the artery of the bulb of penis/vestibule?
Bulb of penis/bulb of vestibule and bulbourethral gland/greater vestibular gland.
What is the tunica albuginea?
The tunica albuginea is the outer covering of each cavernous body in the penis.
What is the perineal body?
A central tendon at the midpoint of the line dividing the perineum.
What does the external pudendal artery (superficial and deep branches) supply in females?
Mons pubis and anterior aspect of labia.
Where is the body of the penis suspended from?
The body of the penis is suspended from the pubic symphysis.
What is the superficial fatty layer of the perineal fascia continuous with in females?
The substance of labia majora and mons pubis, and anteriorly and superiorly with abdominal Camper fascia.
Where do the ducts of the paraurethral glands open?
On each side of the external urethral orifice.
How are the testes suspended in the scrotum?
By the spermatic cords.
What is the rete testis?
A network of canals in the mediastinum of the testis where seminiferous tubules are joined by straight tubules.
Where does the lymph from the area inferior to the pectinate line drain?
Superficial inguinal nodes.
What are the contents of the deep perineal pouch in males?
Intermediate part of the urethra, deep transverse perineal muscles, bulbourethral glands, and dorsal neurovascular structures of the penis.
What forms the apex of the ischio-anal fossae?
The apex is superiorly where levator ani arises from the obturator fascia.
What forms the wide base of the ischio-anal fossae?
The wide base is inferiorly at the skin of the anal region.
Where does the right testicular vein drain?
Into the inferior vena cava (IVC).
Which muscles does the deep perineal fascia invest?
Ischiocavernosus, bulbospongiosus, and superficial transverse perineal muscles.
To what is the deep perineal fascia attached laterally?
Ischiopubic rami.
Into how many parts is the male urethra subdivided?
Four parts: Intramural (preprostatic), Prostatic, Intermediate, and Spongy.
What separates the perineum from the pelvic cavity?
The fascia covering the inferior aspect of the pelvic diaphragm.
Which muscles are part of the pelvic diaphragm?
Levator ani and coccygeus.
Where does the perineal artery arise and what does it supply?
Arises within pudendal canal and supplies superficial perineal muscles and scrotum of male/vestibule of female.
Describe the course of the anal canal.
The anal canal begins as the rectal ampulla narrows proximal to the puborectalis of levator ani and descends posteroinferiorly between the anococcygeal ligament and perineal body.
Which lymph nodes drain the spongy urethra?
Deep inguinal nodes.
What is the insertion of the bulbospongiosus muscle in females?
Pubic arch and fascia of corpora cavernosa of clitoris.
What are the attachments of the external anal sphincter?
The external anal sphincter attaches anteriorly to the perineal body, posteriorly to the coccyx, and superiorly it blends with the puborectalis.
What is the function of the Dartos muscle in the scrotum?
It attaches to the skin and causes wrinkling of the scrotum.
What is the main action of the ischiocavernosus muscle?
Maintains erection of penis or clitoris by compressing outflow.
What is the pectinate (dentate) line and what does it indicate?
The pectinate (dentate) line indicates the junction of the superior and inferior parts of the anal canal. The superior part is visceral and derived from the embryonic hindgut, while the inferior part is somatic and derived from the embryonic proctodeum.
Which artery supplies the anal canal superior to the pectinate line?
Superior rectal artery.
Which nerve gives rise to the anterior labial/scrotal nerves?
Ilioinguinal nerve (L1).
Which nerve's perineal branch arises deep to the inferior border of the gluteus maximus?
Perineal nerve from posterior cutaneous nerve of the thigh (S1-S3).
Which plexus provides innervation superior to the pectinate line?
Inferior hypogastric plexus.
Which nerves provide innervation inferior to the pectinate line?
Inferior anal nerves from the pudendal nerve.
What is the anterior attachment of the deep membranous layer in females?
Continuous with Scarpa fascia of abdomen after passing superiorly to fatty layer of labia majora.
What is the mons pubis?
A rounded fatty eminence anterior to the pubic symphysis, pubic tubercles, and superior pubic rami, covered with coarse pubic hairs after puberty.
How long is the ductus deferens?
25 cm.
What are the anterior boundaries of the ischio-anal fossae?
Bodies of the pubic bones.
What artery supplies blood to the ductus deferens?
Deferential artery from the superior (occasionally inferior) vesical artery.
What is the origin of the external anal sphincter muscle?
Skin and fascia surrounding the anus, coccyx via anococcygeal ligament.
Which artery leaves the pelvis through the greater sciatic foramen and enters the perineum via the lesser sciatic foramen?
Internal pudendal artery.
What forms the lateral boundaries of the superficial perineal pouch?
Ischiopubic rami and obturator internus.
Which veins drain the male urethra?
The dorsal vein of the penis.
What are the posterolateral boundaries of the perineum?
The sacrotuberous ligaments.
What does the deep artery of penis/clitoris supply?
Erectile tissue of corpora cavernosa of penis or clitoris via helicine arteries.
What is Buck's fascia?
Buck's fascia is the deep fascia of the penis, superficial to the tunica albuginea and a continuation of the deep perineal (Gallaudet) fascia.
Where is the perineal body located?
Deep to the skin with little subcutaneous tissue, posterior to the vestibule of the vagina/bulb of the penis, and anterior to the anus and anal canal.
What is the glans penis?
The glans penis is the distal conical expansion of the corpus spongiosum.
What replaces the superficial fatty layer in the urogenital triangle in males?
The dartos muscle in the penis and scrotum.
What is the innervation of the anterior surface of the scrotum?
Anterior scrotal nerves of the ilioinguinal nerve.
What is the innervation of the anterolateral surface of the scrotum?
Genital branch of the genitofemoral nerve.
Where do the ducts of the lesser vestibular glands open?
Into the vestibule between the urethral and vaginal orifices.
Into which vein does the superior rectal vein drain?
Inferior mesenteric vein.
Where are the ischio-anal fossae located?
On each side of the anal canal.
What is the function of the epididymis?
Sperm storage and maturation.
Where does the perineal nerve arise and what is its course?
Arises near the entrance to the pudendal canal and parallels the parent nerve to the end of the canal, passing medially.
What neurovascular structures are found in the deep perineal pouch of males?
Dorsal neurovascular structures of the penis.
What are the posterior boundaries of the ischio-anal fossae?
Sacrotuberous ligament and gluteus maximus.
What are the labia minora?
Rounded folds of fat-free, hairless skin with a core of spongy connective tissue and erectile tissue at their base, forming two laminae anteriorly.
What happens to the posterior commissure after the first vaginal birth?
It disappears.
What forms the prepuce of the clitoris?
The lateral laminae of the labia minora unite anterior to the glans clitoris to form the prepuce.
What are the anterior boundaries of the perineum?
The pubic symphysis.
What does the posterior scrotal/labial artery supply?
Skin of scrotum or labia majora and minora.
What is the internal anal sphincter and what stimulates its contraction?
The internal anal sphincter is an involuntary sphincter that surrounds the superior 2/3 of the anal canal. Its contraction is stimulated by sympathetic fibers from the superior rectal and hypogastric plexuses.
What is the innervation of the intermediate part of the male urethra?
Prostatic nerve plexus from the inferior hypogastric plexus (autonomic).
What is the main action of the bulbospongiosus muscle in females?
Supports and fixes perineal body/pelvic floor, acts as a 'sphincter' of the vagina, assists in erection of clitoris, compresses greater vestibular gland.
What are anal columns and what do they contain?
Anal columns are longitudinal ridges in the superior half of the mucosa of the anal canal, containing terminal branches of the superior rectal artery and vein.
What is the scrotal raphe?
An indication of bilateral embryonic formation of the scrotum, continuous with the penile raphe and perineal raphe.
What is the origin of the superficial transverse perineal muscles?
Passes along inferior aspect of posterior border of perineal membrane to perineal body.
What is the arterial supply of the penis?
The arterial supply of the penis includes the dorsal arteries of the penis, deep arteries of the penis, arteries of the bulb of the penis, and branches of the external pudendal arteries.
What nerves are involved in the innervation of the penis?
S2-S4
Dorsal nerve of penis(Sensory and symp)
Ilioinguinal nerve(Skin of root)
Cavernous nerves(Erection)
What is the innervation of the posteroinferior surface of the scrotum?
Perineal branch of the posterior cutaneous nerve of the thigh.
Where do the labial veins drain?
Into the internal pudendal vein.
What forms the superior boundary of the deep perineal pouch?
The inferior fascia of the pelvic diaphragm.
What is the tunica albuginea?
The tough fibrous outer surface of the testes.
What is the tunica vaginalis?
A closed peritoneal sac covering the surface of the testis, except where it attaches to the epididymis and spermatic cord.
Which nerve exits the pelvis via the infrapiriform part of the greater sciatic foramen?
Pudendal nerve (S2-S4).
What is the pampiniform venous plexus?
A network of veins that drains into the right and left testicular veins.
What is another name for the deep perineal fascia?
Gallaudet fascia or investing fascia.
Describe the labia majora.
Prominent folds of skin filled with loose subcutaneous tissue, containing smooth muscles and the termination of the round ligament of the uterus, passing inferoposteriorly from the mons pubis toward the anus.
What is the primary content of the spermatic cord?
Ductus deferens.
What is the clitoris composed of?
A root and a small cylindrical body composed of 2 crura, 2 corpora cavernosa, and the glans clitoris.
What is the venous drainage of the ductus deferens?
Testicular vein and distal pampiniform plexus.
What is the main action of the external anal sphincter?
Constricts anal canal during peristalsis, supports and fixes perineal body and pelvic floor.
What does the inferior rectal artery supply?
Anal canal inferior to pectinate line, anal sphincters, and peri-anal skin.
What is the extent of the anal canal?
The anal canal extends from the superior aspect of the pelvic diaphragm to the anus.
What are the main parts of the penis?
The penis consists of a root, body, and glans.
What is the origin of the bulbospongiosus muscle in females?
Perineal body.
What is the external anal sphincter and where is it located?
The external anal sphincter is a voluntary sphincter that forms a broad band on each side of the inferior 2/3 of the anal canal.
What are the two layers of the scrotum?
Heavily pigmented skin and Dartos fascia.
What is the insertion of the ischiocavernosus muscle?
Inferior and medial aspects of crus, perineal membrane medial to crus.
What are anal valves and sinuses?
Anal valves are formed by the union of anal columns inferiorly, with depressions above them called anal sinuses.
Which veins drain the scrotum?
Veins accompanying the arteries, draining into the external pudendal veins.
Where does lymph drainage of the penis occur?
Lymph drainage of the penis occurs in the superficial inguinal nodes.
What is the function of the greater vestibular glands?
To secrete mucus into the vestibule during sexual arousal.
Which nerves provide parasympathetic innervation to the erectile bodies of vulva?
Cavernous nerves from the uterovaginal plexus.
What is the anterior attachment of the deep membranous layer in males?
Dartos fascia of scrotum and penis.
What are the functions of the vulva?
Sensory and erectile tissue for sexual arousal and intercourse, directs the flow of urine, prevents entry of foreign material into the urogenital tract.
What is the venous drainage of the epididymis?
Pampiniform plexus from the testicular vein.
What is the course of the deep perineal nerve?
Arises in the anterior (terminal) end of the pudendal canal and passes medially then deeply in the superficial perineal pouch.
What is the innervation of the testes?
The testicular nerve plexus on the testicular artery, originating from T10 and/or T11.
What is the anterior recess of the ischio-anal fossae?
Extensions into the urogenital triangle superior to the perineal membrane.
What forms the floor of the superficial perineal pouch?
Perineal (Colle’s) fascia.
What forms the roof of the superficial perineal pouch?
Perineal membrane.
What is the terminal part of the large intestine called?
The terminal part of the large intestine is called the anal canal.
What are the lateral boundaries of the perineum?
The ischial tuberosities.
What is the main action of the bulbospongiosus muscle in males?
Supports and fixes perineal body/pelvic floor, compresses bulb of penis to expel last drops of urine/semen, assists erection by compressing outflow.
What inhibits the contraction of the internal anal sphincter?
The contraction of the internal anal sphincter is inhibited by parasympathetic fibers from the pelvic splanchnic nerves.
What is the innervation of the spongy urethra?
Dorsal nerve of the penis from the pudendal nerve (somatic).
What is the origin of the ischiocavernosus muscle?
Internal surface of ischiopubic ramus and ischial tuberosity.
What indicates the anorectal junction?
The anorectal junction is indicated by the superior ends of the anal columns.
What is the main action of the superficial transverse perineal muscles?
Supports and fixes perineal body/pelvic floor to support abdominopelvic viscera, resists increased intra-abdominal pressure.
What is the origin of the external urethral sphincter?
Surrounds urethra superior to perineal membrane, ascends anterior aspect of prostate, fibers enclose vagina (urethrovaginal sphincter).
What is the main action of the external urethral sphincter?
Compresses urethra, urethrovaginal sphincter portion also compresses vagina.
What is the function of the lesser vestibular glands?
To secrete mucus into the vestibule to moisten the labia and vestibule.
What is the innervation of the external anal sphincter?
Inferior anal (rectal) nerve.
What are the contents of the superficial perineal pouch in males?
Root (bulb and crura) of penis, ischiocavernosus and bulbospongiosus, proximal part of spongy urethra, superficial transverse perineal muscles, deep perineal branch of internal pudendal vessels, and pudendal nerves.
Which lymph nodes drain the intermediate part of the male urethra?
Internal iliac nodes.
What are the posterior boundaries of the perineum?
The inferior-most sacrum and coccyx.
Which areas are supplied by the dorsal artery of penis/clitoris?
Deep perineal pouch, skin of penis, fascia of penis or clitoris, distal corpus spongiosum of penis, spongy urethra, and glans penis or clitoris.
What is the function of the corpus spongiosum?
The corpus spongiosum contains the spongy urethra and is separated from the corpora cavernosa by the intercavernous septum of deep (Buck) fascia.
Which muscles attach to the perineal body?
Bulbospongiosus, external anal sphincter, superficial and deep transverse muscles, external urethral sphincter, and levator ani.
What is the function of the suspensory ligament of the penis?
The suspensory ligament of the penis is a deep fascia from the anterior pubic symphysis that passes inferiorly and splits to form a sling, attaching to the deep (Buck) fascia of the penis at the junction of the root and body.
Where do the ducts of the greater vestibular glands open?
At the upper medial aspects of the labia minora.
Where are the greater vestibular glands (Bartholin glands) located?
In the superficial perineal pouch, on each side of the vestibule of the vagina
Which nerves provide innervation to the posterior labia?
Posterior labial nerves from the pudendal nerve.
What does the external pudendal artery (superficial and deep branches) supply in males?
Anterior aspect of scrotum and skin at root of penis.
What structures make up the root of the penis?
The root of the penis consists of the crura, bulb, ischiocavernosus muscles, and bulbospongiosus muscle.
What are the layers of the perineal fasciae?
Superficial (subcutaneous tissue) and deep (Gallaudet/investing) fascia.
Which lymph nodes drain the scrotum?
Superficial inguinal nodes.
What is the innervation of the posterior surface of the scrotum?
Posterior scrotal nerves of the pudendal nerve.
What are the bulbs of the vestibule and where are they located?
Paired masses of elongated erectile tissue lying along the sides of the vaginal orifice immediately inferior to the perineal membrane.
Lymph drainage of external female genitalia?
Superficial inguinal LN
What is the origin of the deep transverse perineal muscle?
Passes along superior aspect of posterior border of perineal membrane to perineal body and external anal sphincter.
What is the innervation of the external urethral sphincter?
Dorsal nerve of penis/clitoris.
Which muscle covers the bulbs of the vestibule inferiorly and laterally?
The bulbospongiosus muscles.
Which nerves provide innervation to the anterior labia?
Anterior labial nerves from the ilioinguinal nerve.
What determines the size of the vaginal orifice?
The condition of the hymen, which is a thin annular fold of mucus membrane.
Where does the deep membranous layer(Colles fascia) not extend?
Into the anal triangle.
What are the contents of the ischio-anal fossae?
Fatty tissue, internal pudendal vessels and pudendal nerve(Pudendal canal), inferior rectal nerves and vessels, posterior scrotal nerve and vessels, perineal branch of S4, perforating cutaneous (cluneal) nerves, and lymphatics.
Where do the contents of the pudendal canal enter the canal?
Lesser sciatic notch
What is the pudendal canal and where is it located?
Horizontal passageway within the obturator fascia, lining the medial aspect of the obturator internus and the lateral wall of the ischio-anal fossae.
Where does the lymph from the area superior to the pectinate line drain?
Internal iliac nodes(common iliac, and lumbar nodes.)
Which arteries supply the scrotum?
Posterior Scrotal Branches
Anterior Scrotal branches
Cremasteric Artery
How is the venous drainage of the penis organized?
Cavernous spaces: Deep dorsal vein of penis(Prostatic plexus)
Skin: Superficial dorsal veins to superficial external pudendal vein
What arteries supply the external female genitalia?
External pudendal arteries and labial and clitoral branches of the internal pudendal artery.
