Urogenital Triangle

Gross Anatomy


Urogenital Triangle - Male and Female


Anatomy Tables for Today's Topic

Muscles of the Urogenital Triangle
Nerves of the Urogenital Triangle
Arteries of the Urogenital Triangle
Veins of the Urogenital Triangle
Viscera of the Urogenital Triangle

Muscles of the Urogenital Triangle

Muscle Origin Insertion Action Innervation Artery Notes
bulbospongiosus, in female perineal body and fascia of the bulb of the vestibule perineal membrane and corpus cavernosum of the clitoris compresses the vestibular bulb and constricts the vaginal orifice deep branch of the perineal nerve (from pudendal nerve) perineal a. skeletal muscle
bulbospongiosus, in male central tendinous point and the midline raphe on the bulb of the penis perineal membrane, dorsal surface of the corpus spongiosum, deep penile fascia compresses the bulb of the penis, compresses the spongy urethra deep branch of the perineal nerve (from pudendal nerve) perineal a. expels the last drops of urine from urethra; expels semen during ejaculation
ischiocavernosus medial surface of the ischial tuberosity and the ischiopubic ramus corpus cavernosum and crus of the penis/clitoris compresses the corpus cavernosum deep branch of the perineal nerve (from pudendal nerve) perineal a. ischiocavernosus m. is closely applied to the surface of the crus penis/clitoris
transverse perineus, deep medial surface of the ischial ramus contralateral muscle and perineal body/central tendinous point fixes and stabilizes the perineal body/central tendinous point deep branch of perineal nerve from pudendal nerve internal pudendal a. superficial and deep transverse perineus muscles are separated by the perineal membrane
transverse perineus, superficial medial surface of the ischial ramus contralateral muscle and the perineal body/central tendinous point fixes and stabilizes perineal body/central tendinous point deep branch of perineal nerve from pudendal nerve perineal a. superficial and deep transverse perineus muscles are separated by the perineal membrane

Nerves of the Urogenital Triangle

Nerve Source Branches Motor Sensory Notes
dorsal n., of the clitoris pudendal n. no named branches sympathetic motor innervation to skin skin of the shaft of the clitoris the terminal branch of the pudendal n.
dorsal n., of the penis pudendal n. no named branches sympathetic motor innervation to skin skin of the shaft of the penis the terminal branch of the pudendal n.
labial, anterior ilioinguinal n. no named branches none skin of the anterior aspect of the labium majus communicates with the genital br. of the genitofemoral n.
labial, posterior perineal n. (a branch of the pudendal n.) no named branches none skin of the posterior aspect of the labium majus communicates with the perineal br. of the posterior femoral cutaneous n.
pudendal n. ventral primary rami of spinal nerves S2-S4 (sacral plexus) inferior rectal n., perineal n., dorsal n. of the clitoris/penis its branches supply: external anal sphincter, bulbospongiosus m., ischiocavernosus m., superficial & deep transverse perineus mm., sphincter urethrae m., sphincter urethrovaginalis, compressor urethrae its branches supply: skin of the anus, posterior scrotum/labium majus, clitoris/penis pudendal n. passes through the pudendal canal formed by fascia on the medial surface of the obturator internus m.
rectal, inferior pudendal n. no named branches external anal sphincter skin of the anus inferior rectal nerve is one of the first branches of the pudendal n.
scrotal, anterior anterior cutaneous br. of the ilioinguinal n. no named branches none skin of the anterior aspect of the scrotum anterior scrotal n. is the continuation of the ilioinguinal n. at the superficial inguinal ring; it communicates with the genital br. of the genitofemoral n.
scrotal, posterior perineal n., from the pudendal n. no named branches none skin of the posterior aspect of the scrotum posterior scrotal n. communicates with the perineal br. of the posterior femoral cutaneous n.

Arteries of the Urogenital Triangle

Artery Source Branches Supply to Notes
of bulb of penis internal pudendal a. no named branches bulb of the penis and associated tissues artery of the bulb of the penis courses within the deep perineal space to enter the deep surface of the bulb
of bulb of vestibule internal pudendal a. no named branches bulb of the vestibule and associated tissues artery of the bulb of the vestibule courses within the deep perineal space to enter the deep surface of the bulb
deep, of clitoris internal pudendal a. no named branches corpus cavernosum of the clitoris deep a. of the clitoris and dorsal a. of the clitoris are the terminal brs. of the internal pudendal a.
deep, of penis internal pudendal a. no named branches corpus cavernosum of the penis deep a. of the penis and dorsal a. of the penis are the terminal brs. of the internal pudendal a.
dorsal, of clitoris internal pudendal a. no named branches superficial tissues of the clitoris dorsal a. of the clitoris and deep a. of the clitoris are the terminal brs. of the internal pudendal a.
dorsal, of penis internal pudendal a. no named branches superficial tissues of the penis dorsal a. of the penis and deep a. of the penis are the terminal brs. of the internal pudendal a.
labial, posterior perineal a. no named branches posterior aspect of the labium majus posterior labial a. courses through the superficial perineal space
perineal internal pudendal a. posterior labial/scrotal; deep br. posterior aspect of the scrotum/labium majus; muscles of the superficial perineal space perineal a. courses superficial to the superficial transverse perineus m.; it courses with the perineal n.
pudendal, deep external femoral a. unnamed muscular branches origins of pectineus m., adductor longus m.; scrotum/labium majus deep external pudendal a. may arise from the medial circumflex femoral a.
pudendal, internal internal iliac a., anterior division inferior rectal a., perineal a., artery of the bulb of the clitoris/penis, urethral a., deep clitoral/penile a., dorsal clitoral/penile a. anus, muscles of the superficial and deep perineal spaces, clitoris/penis, posterior aspect of the scrotum/labium majus internal pudendal a. is the primary blood supply to the perineum
pudendal, superficial external femoral a. no named branches skin and superficial fascia of the upper medial thigh, skin of the pubic region superficial external pudendal a. is one of three superficial branches of the femoral a. near the inguinal ligament (see also: superficial circumflex iliac a., superficial epigastric a.)
rectal, inferior internal pudendal a. no named branches anus, ischioanal fossa inferior rectal a. anastomoses with the middle rectal a. and the superior rectal a.
scrotal, posterior perineal a. no named branches posterior aspect of the scrotum posterior scrotal a. passes superficial to the superficial transverse perineus m.

Veins of the Urogenital Triangle

Vein Tributaries Drains Into Regions Drained Notes
of clitoris, deep dorsal many unnamed tributaries vesical venous plexus erectile tissue of the clitoris deep dorsal v. of the clitoris passes anterosuperior to the urogenital diaphragm (between the arcuate pubic ligament and the transverse ligament of the perineum) to enter the pelvic cavity; an unpaired vein
of clitoris, superficial dorsal no named tributaries superficial external pudendal v. skin and superficial fascia of the clitoris superficial dorsal v. of the clitoris is located superficial to the deep fascia of the clitoris
of penis, deep dorsal many unnamed tributaries prostatic venous plexus erectile tissue of the penis deep dorsal v. of the penis passes anterosuperior to the urogenital diaphragm (between the arcuate pubic ligament and the transverse ligament of the perineum) to enter the pelvic cavity; an unpaired vein
of penis, superficial dorsal no named tributaries superficial external pudendal v. skin and superficial fascia of the penis superficial dorsal v. of the penis is located superficial to the deep fascia of the penis
pudendal, deep external part of the drainage of the superficial dorsal v. of the penis/clitoris femoral skin and superficial fascia of the penis/clitoris; pubic region deep external pudendal v. shares its region of drainage with the superficial external pudendal v.
pudendal, internal deep dorsal v. of the penis/clitoris, v. of the bulb, posterior labial/scrotal v., inferior rectal v. internal iliac crus and bulb of the clitoris/penis; urogenital region, anal region internal pudendal v. passes through the pudendal canal
pudendal, superficial external part of the drainage of the superficial dorsal v. of the penis/clitoris great saphenous skin and superficial fascia of the penis/clitoris; pubic region superficial external pudendal v. shares its region of drainage with the deep external pudendal v.

Viscera of the Urogenital Triangle

Organ/Part of Organ Location/Description Notes
clitoris combination of 3 erectile bodies: glans clitoris and 2 corpora cavernosa clitoris clitoris is covered by smooth skin
corpus cavernosum primary erectile bodies (paired) of the penis and clitoris corpora cavernosa attach via the crura to the ischiopubic rami and the perineal membrane; each crus is covered by an ischiocavernosus muscle; supplied by the deep a. of the penis/clitoris
corpus spongiosum midline erectile body, attached to the perineal membrane at its proximal end (bulb of the penis) corpus spongiosum expands distally as the glans penis which caps the distal ends of the corpora cavernosa; it contains the spongy/penile urethra
crus clitoris lateral part of the corpus cavernosum which is attached to the ischiopubic ramus and the perineal membrane crus clitoris is covered on its superficial surface by the ischiocavernosus muscle
crus of penis lateral part of the corpus cavernosum which is attached to the ischiopubic ramus and the perineal membrane crus penis is covered on its superficial surface by the ischiocavernosus muscle
fossa navicularis dilation of the spongy/penile urethra in the glans penis the largest diameter of the penile urethra occurs here
fundiform ligament specialization of the membranous layer of superficial (Scarpa's) fascia passing from the lower abdominal wall onto the base of the penis/clitoris suspensory ligament of the penis/clitoris is a deep fascia specialization that lies deep to the fundiform ligament
glans penis/clitoridis expanded distal end of the corpus spongiosum which caps the ends of the corpora cavernosa the fossa navicularis is an expanded portion of the penile urethra that occurs in the glans
greater vestibular gland an exocrine gland located in the superficial perineal space posterior to the bulb of the vestibule greater vestibular gland is covered by the bulbospongiosus muscle; it produces a mucous secretion that drains into the vestibule of the vagina for lubrication of the vulva
hymen thin, usually incomplete septum at the inferior vaginal orifice the hymen is the remnant of the urogenital septum of the embryo, and the hymeneal caruncles are remnants of the hymen
labia majora fat-filled elevations of hair-covered skin lying on either side of the vestibule of the vagina labia majora are joined across the midline by the anterior and posterior labial commissures; they blend into each other anteriorly to form the mons pubis
labia minora paired folds of hairless skin located medial to the labia majora and extending posteroinferiorly from the clitoris the anterior end of each labium minus divides: the anterior division of each labium forms the prepuce of the clitoris and the posterior division of each labium forms the frenulum of the clitoris
perineal membrane membrane stretching across the urogenital triangle attaching to both ischiopubic rami perineal membrane is pierced by the urethra, vagina and branches of the pudendal neurovascular bundle
prepuce fold of smooth skin extending over the glans penis/clitoris the anterior divisions of the labia minora combine to form the prepuce of the clitoris
scrotum sac of hair-covered skin containing the testis in the scrotum the fatty and membranous layers of the superficial fascia (as seen in the lower abdominal wall) are fused to form the tunica dartos scroti
suspensory ligament of the penis/clitoris a specialization of deep fascia connecting the proximal end of the penis/clitoris to the pubis and pubic symphysis the fundiform ligament is a specialization of superficial fascia that lies superficial to the suspensory ligament
testis an endocrine and exocrine gland contained within the scrotum testis is the male gonad; its exocrine product is sperm which drain to the head of the epididymis via efferent ductules; its endocrine product is testosterone; the testis migrates into the scrotum shortly before birth; it is tethered to the scrotum inferiorly by the scrotal ligament (a remnant of the gubernaculum)
vagina part of the female genital canal located between the vestibule and the cervix vaginal fornices surround the cervix; the word "vagina" is derived from the Latin word for sheath
vestibule of the vagina region inferior to the hymen/hymeneal caruncles and between the labia minora vestibule of the vagina contains the external urethral orifice, the opening of the vagina and the openings of the greater vestibular glands

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Some of the material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest and Jaye Schlesinger
Published by ILOC, Inc., New York. Copyright 1995.

Content of these tables has been edited for use in this course by Patrick W. Tank, Ph.D.
Copyright 2005, Department of Neurobiology and Developmental Sciences, University of Arkansas for Medical Sciences.

Unauthorized use is prohibited.