Anatomy Tables - External Female Genitalia

Osteology
Bone Structure Description Notes
pubis (TG6-03, TG6-03) an angulated bone the forms the anterior part of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis; its body forms 1/5 of the acetabulum; its symphyseal surface unites with the pubis of the opposite side to form the pubic symphysis; the superior and inferior pubic rami participate in the formation of the obturator foramen
inferior ramus inferior "limb" that passes inferolaterally from the pubic symphysis articulates with the ischial ramus to form the ischiopubic ramus; attachment site for the root of the penis (clitoris) (Latin, ramus = a branch)
pubic symphysis (N248, TG5-03) the midline joint uniting the superior rami of the two pubic bones a symphysis; a fibrocartilage interpubic disk unites the bones; the subpubic angle (at the pubic arch) in the female is greater than the subpubic angle in the male (Greek, symphysis = a growing together)
ischium (N486, TG3-04)   the "V"- shaped bone that forms the posteroinferior part of the pelvis one of the three bones that form the os coxae: ilium, ischium, pubis
  ischial ramus the limb of the ischium that passes anteriorly and superomedially toward the pubis it articulates with the inferior ramus of the pubis to form the ischiopubic ramus (Greek, ischion = hip joint; Latin, ramus = a branch)
ischial tuberosity the roughened projection that protrudes posteroinferiorly from the body of the ischium it is the site of attachment of the sacrotuberous ligament; it is the site of origin of the inferior gemellus m., quadratus femoris m. and the hamstring mm. (semitendinosus, semimembranosus, long head of biceps femoris, ischiocondylar portion of the adductor magnus) (Greek, ischion = hip joint)
lesser sciatic notch the notch located between the ischial tuberosity and the ischial spine the lesser sciatic notch is converted to the lesser sciatic foramen by the sacrospinous ligament and the sacrotuberous ligament
ischial spine the spine that arises just superior to the lesser sciatic notch it is the site of attachment of t he sacrospinous ligament and the site of origin of the superior gemellus m. (Greek, ischion = hip joint)
ilium (N486, TG3-04) fan-shaped bone that forms the lateral prominence of the pelvis one of three bones that form the os coxae: ilium, ischium, pubis
greater sciatic notch the notch on the inferior portion of ilium located posteromedial to the ischial spine the greater sciatic notch is converted to the greater sciatic foramen by the sacrospinous ligament and the sacrotuberous ligament
coccyx (N248, TG5-03) the most inferior portion of the vertebral column the coccyx results from the fusion of the four coccygeal vertebrae; it may be a single bone or the first coccygeal vertebra may be separated from the other three; it articulates with the fifth sacral segment; coccygeal vertebrae are reduced in complexity, having no pedicles, laminae or spines (Latin, coccyx = a crow's beak)

Joints
Joint Description Significance
sacrospinous ligament (N353, N503, TG6-06, TG3-28) the ligament that connects the ischial spine to the lateral surface of the sacrum and coccyx together with the sacrotuberous ligament, it converts the greater and lesser sciatic notches into greater and lesser sciatic foramina
sacrotuberous ligament (N353, N503, TG6-06 the ligament that connects the ischial tuberosity to the lateral surface of the sacrum and coccyx together with sacrospinous ligament, it converts the greater and lesser sciatic notches into greater and lesser sciatic foramina

Muscles
Muscle Origin Insertion Action Innervation Artery Notes Image
anal sphincter, external (N390, N392, N393, N394, TG6-15, TG6-27) perineal body or central tendinous point of the perineum encircles the anal canal; superficial fibers attach to the coccyx constricts the anal canal inferior rectal nerves (from the pudendal nerve) inferior rectal a. skeletal (voluntary) muscle, as contrasted with sphincter ani internus, which is smooth (involuntary) muscle; the external anal sphincter is considered part of the pelvic diaphragm (Greek, sphincter = that which binds tight)
bulbospongiosus, in female (N379, N382, TG6-27A, TG6-27B) 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
ischiocavernosus (N379, N382, TG6-27A, TG6-27B) 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
obturator internus (N358, N360, N379, TG6-21, TG6-21, TG3-28) the internal surface of the obturator membrane and margin of the obturator foramen greater trochanter on its medial surface above the trochanteric fossa laterally rotates and abducts the thigh nerve to the obturator internus m. obturator a. the obturator internus m. leaves the pelvis by passing through the lesser sciatic foramen; the superior and inferior gemellus mm. insert on the obturator internus tendon
sphincter urethrae, in female (N361, N366, N379, N382, N385, TG6-08, TG6-10, TG6-28A, TG6-28B) encircles the urethra encircles urethra and vagina; extends superiorly along the urethra as far as the inferior surface of the bladder compresses urethra and vagina deep branch of perineal nerve from pudendal nerve internal pudendal a. skeletal muscle (Greek, sphincter = that which binds tight)
superficial transverse perineus 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
deep transverse perineus 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

Nerves
Nerve Source Branches Motor Sensory Notes
anterior labial n. (TG6-19A) ilioinguinal n. no named branches none skin of the anterior aspect of the labium majus communicates with the genital br. of the genitofemoral n. (Latin, labial = lips)
dorsal n. of the clitoris (TG6-19A) pudendal n. no named branches sympathetic motor innervation to skin skin of the shaft of the clitoris the terminal branch of the pudendal n.
inferior rectal n. (TG6-19A) 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.
perineal n. (TG6-19B) pudendal posterior scrotal/labial n., deep (muscular) br. muscles of the perineum: bulbospongiosus m., ischiocavernosus m., superficial and deep transverse perineus mm., sphincter urethrae m., sphincter urethrovaginalis, compressor urethrae skin of the posterior surface of the scrotum/labium majus perineal n.branches from the pudendal n. at the posterior margin of the transverse perineal muscles
plexus, rectal (TG6-19B) inferior hypogastric (pelvic) plexus, posterior part no named branches sympathetic: vascular smooth muscle of the pelvic viscera, especially the rectum; parasympathetic: smooth muscle and glands of the pelvic viscera, especially the rectum pain and general sensation from the rectum rectal plexus is continuous with the vesical plexus in the male, uterovaginal plexus in the female (Latin, plexus = a braid. A network of nerves, blood vessels, or lymphatic vessels)
plexus, vesical (TG6-19B) inferior hypogastric plexus continuous with the prostatic plexus sympathetic: vascular smooth muscle of the pelvic viscera, especially the urinary bladder, seminal vesicle, ductus deferens and ejaculatory duct; parasympathetic: smooth muscle and glands of the pelvic viscera, especially the urinary bladder, seminal vesicle, ductus deferens and ejaculatory duct pain and general sensation from the bladder, seminal vesicle and ductus deferens vesical plexus is continuous with the other autonomic nerve plexuses in the pelvis and cannot be distinguished from them (Latin, plexus = a braid. A network of nerves, blood vessels, or lymphatic vessels)
posterior labial n. (TG6-19A) 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. (Latin, labial = lips)
pudendal n. (N404, N405, TG6-28A, TG6-28B, TG6-29A, TG6-29B, TG6-30A, TG6-30B) 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. (Latin, pudendus = ashamed, the term referred to "the shameful parts", ie the genitals)
uterovaginal plexus (TG6-19A) inferior hypogastric plexus continuous with the rectal plexus sympathetic: vascular smooth muscle of the pelvic viscera, especially the uterus, uterine tubes and vagina; parasympathetic: smooth muscle and glands of pelvic viscera, especially uterus, uterine tubes and vagina pain from the pelvic viscera listed at left the uterovaginal plexus is a subsidiary plexus of the inferior hypogastric plexus (Latin, plexus = a braid. A network of nerves, blood vessels, or lymphatic vessels)

Arteries
Artery Source Branches Supply to Notes
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
clitoris, deep a. of (N404, N405, TG6-29A, TG6-29B, TG6-30A, TG6-30B) 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.
clitoris, dorsal a. of (N404, N405, TG6-29A, TG6-29B, TG6-30A, TG6-30B) internal pudendal a. no named branches superficial structures of the clitoris dorsal a. of the clitoris and deep a. of the clitoris are the terminal brs. of the internal pudendal a.
inferior rectal (TG6-28B, TG6-31B) internal pudendal a. no named branches anus, ischioanal fossa inferior rectal a. anastomoses with the middle rectal a. and the superior rectal a.
internal pudendal (N404, N405, TG6-28A, TG6-28B, TG6-29A, TG6-29B, TG6-30A, TG6-30B) 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
perineal (TG6-29A, TG6-29B) 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.
posterior labial (TG6-29A) perineal a. no named branches posterior aspect of the labium majus posterior labial a. courses through the superficial perineal space

Veins
Vein Tributaries Drains Into Regions Drained Notes
internal pudendal v. (TG6-31B) v. of the bulb, posterior labial/scrotal v., inferior rectal v. internal iliac bulb of the clitoris/penis; urogenital region, anal region NOTE: deep dorsal vein, which drains the erectile bodies, does NOT pass to internal pudendal vein (Latin, pudendus = ashamed, the term referred to "the shameful parts", ie. the genitals)
of clitoris, deep dorsal (N N265, N359, N381, N405, TG6-31B, TG6-32B) many unnamed tributaries vesical venous plexus erectile tissue of the clitoris deep dorsal v. of the clitoris passes 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

Viscera
Organ/Part of Organ Location/Description Notes
clitoris (N377, TG6-25) combination of 3 erectile bodies: glans clitoris and 2 corpora cavernosa clitoris clitoris is covered by smooth skin
corona of the glans (N382) margin of the glans projecting beyond the ends of the corpora cavernosa overhangs the neck of the glans that separates the body from the glans of the penis
external urethral meatus (orifice) (female) (N377, TG6-25) opening of the membranous urethra into the vestibule of the vagina between the clitoris and the vaginal orifice
frenulum (N377, TG6-25) a more posterior or deeper part of the labia minora passing posterior to the clitoris (Latin, frenulum = bridle, a narrow reflection of membrane from the lower surface of the glands with the prepuce)
glans penis/clitoridis (N377, TG6-25, N382) expanded distal end of the corpus spongiosum which caps the ends of the corpora cavernosa (Latin, glans = acorn)
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 (Greek, hymen = a membrane)
labia majora (N377, TG6-25) 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 (Latin, labia = lips)
labia minora (N377, TG6-25) 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 (Latin, labia = lips)
mons pubis (N377, TG6-25) rounded, fatty prominence anterior to the pubic symphysis (Latin, mons = mountain)
prepuce (N377, TG6-25) 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 (Latin, praeputium = foreskin)
urethra (NN366, TG6-10, N378, TG6-10, N385) duct that drains the urinary bladder urethra has three parts in the male: prostatic, membranous & penile/spongy; female urethra is much shorter than the male urethra, consisting of the membranous part only
urethra, membranous (N385) part of the urethra that passes through the sphincter urethrae muscle and perineal membrane female: membranous urethra connects the urinary bladder to the external urethral orifice at the vestibule of the vagina; male: membranous urethra connects the prostatic urethra with the spongy/penile urethra
vagina (N377, TG6-25) 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 (N377, TG6-25) 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
vulva (N377, TG6-25) serves as sensory and erectile tissue for sexual intercourse and arousal, directs the flow of urine, prevents entry of foreign material into the urogenital tract clinically called the pudendum
bulb of the vestibule (TG6-27A) erectile tissue located on either side of the vestibule of the vagina, attached to the perineal membrane bulb of the vestibule is continuous with the glans clitoris; it is covered on its superficial surface by the bulbospongiosus muscle; it is the homologue of the bulb of the penis
corpus cavernosum (N379, N382, N418, TG6-27A, TG6-27B) 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 (Latin, corpus = body)
crus clitoris (N379, N382, N418, TG6-27A, TG6-27B) 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 (Latin, crus = resembles a leg, therefore any structure which resembles a leg. The clitoris and diaphragm are two among many anatomical structures which take origin from crura)
erectile tissue (N379, N382, N418, TG6-27A, TG6-27B) tissue within the corpora cavernosa erection occurs as a result of blood filling the spaces of the corpora cavernosa
fascia, deep penile/clitoral an extension of the muscular fascia of the ischiocavernosus m. and bulbospongiosus m. onto the shaft of penis/clitoris deep fascia of the penis/clitoris forms a tubular sheath surrounding the erectile bodies, dorsal n. of the penis/clitoris, dorsal a. of the penis/clitoris, deep dorsal v. of the penis/clitoris; the superficial dorsal v. of penis/clitoris lies superficial to the deep fascia of the penis/clitoris; deep fascia of the penis is also known as: Buck's fascia
glans penis/clitoridis (N379, N382, N418, TG6-27A, TG6-27B) expanded distal end of the corpus spongiosum which caps the ends of the corpora cavernosa (Latin, glans = acorn)
greater vestibular gland (N379, TG6-27A) 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
perineal membrane (N381, TG6-27A, TG6-27B) 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
perineal body (TG6-27A) fibrous connective tissue in the midline between the vestibule of the vagina and the anus many of the muscles of the perineum attach at or to the perineal body, including the transverse perineal muscles, bulbospongiosus, and external anal sphincter; the male version is often called the central tendinous point
suspensory ligament of the penis/clitoris (TG6-31BA) 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
tunica albuginea, corpus cavernosum (N379, N382, N418, TG6-27A, TG6-27B) outer white fibrous covering of the corpus cavernosum of the penis/clitoris tunica albuginea is a dense connective tissue layer that is not distensible, causing erection when the corpus cavernosum becomes engorged with blood (Latin, tunica albuginea = white coat + corpus = body)
urethra (N388, TG6-09A, TG6-09B) duct that drains the urinary bladder urethra has three parts in the male: prostatic, membranous & penile/spongy; female urethra is much shorter than the male urethra, consisting of the membranous part only
urethra, membranous (N388, TG6-09A, TG6-09B) part of the urethra that passes through the sphincter urethrae muscle and perineal membrane female: membranous urethra connects the urinary bladder to the external urethral orifice at the vestibule of the vagina; male: membranous urethra connects the prostatic urethra with the spongy/penile urethra

Topographical Anatomy
Structure/Space Description/Boundaries Significance
perineum (N380, TG6-25) a diamond-shaped space forming the outlet of the pelvis; its boundaries are: anterolaterally - inferior pubic ramus, ischial ramus and ischial tuberosity; posterolaterally - sacrotuberous ligament perineum is subdivided into the anal triangle and urogenital triangle by an imaginary line connecting the ischial tuberosities (peri + inan ("to empty out" in Greek))
anal triangle (N380, TG6-25) posterior subdivision of the diamond-shaped perineum; its boundaries are: anteriorly - posterior margin of the perineal membrane (corresponds to an imaginary line connecting the ischial tuberosities); posterolaterally - sacrotuberous ligament anal triangle is the location of the terminal end of the gastrointestinal tract (anus)
urogenital triangle (N380, TG6-25) anterior subdivision of the diamond-shaped perineum; its boundaries are: anterolaterally - inferior pubic ramus, ischial ramus; posteriorly - posterior margin of perineal membrane (corresponds to an imaginary line connecting the ischial tuberosities) urogenital triangle is the location of the terminal portion of the urinary tract and genital tract
ischioanal fossa (TG6-16, TG6-26B, TG6-35, TG6-36) a fat-filled space located lateral to the anal canal and inferior to the pelvic diaphragm; its boundaries are: superomedially - pelvic diaphragm (anterior recess extends superior to the sphincter urethrae muscle); medially - external anal sphincter muscle and anal canal; laterally - obturator internus fascia and ischial tuberosity; posterolaterally - sacrotuberous ligament and gluteus maximus m.; (posterior recess extends superior to the gluteus maximus m.) the fat and loose connective tissue in the ischioanal fossa compresses to allow passage of feces; also known as: ischiorectal fossa (Greek, ischion = hip joint)
natal cleft (TG6-27A) midline cleft between the buttocks natal cleft lies between the gluteus maximus muscles

Lymphatics
Structure Location Afferents from Efferents to Regions drained Notes
iliac nodes, internal (N257, N387, TG6-33, TG6-34) along the internal iliac vessels lymphatic vessels from the pelvic viscera common iliac nodes, external iliac nodes pelvis, perineum and gluteal region internal iliac nodes are 4 to 8 in number
inguinal nodes, superficial (N257, N387, TG6-33, TG6-34) in the superficial fascia parallel to the inguinal ligament and along the terminal part of the greater saphenous v. lymphatic vessels from the superficial lower limb, superficial abdominal wall, perineum external iliac nodes; deep inguinal nodes lower abdominal wall; external genitalia; superficial parts of the lower limb superficial inguinal nodes are 12-20 in number; they become inflamed during infections of the lower limb; they may become inflamed during infections of the external genitalia

Clinical Terms
Term Definition
pudendal nerve block the area anesthetized is the skin of the perineum; this nerve block does not, however, abolish sensation from the anterior part of the perineum, which is innervated by the ilioinguinal nerve and the genitofemoral nerve. It will also not anesthetize the perineal branch of the posterior femoral cutaneous nerve. Also, it does not abolish pain from uterine contractions that ascend to the spinal cord via the sympathetic afferent nerves. In the transvaginal procedure the ischial spine is the landmark used for the insertion of the needle
cystocele a condition where the bladder herniates into the vaginal canal and usually results in stress incontinence. (Greek, -cele = hernia)
colporrhaphy repair of a rupture of the vagina by suturing the edges of the tear.
laparotomy general term for abdominal surgery.
enterocele a hernial protrusion of bowel through a defect in the rectouterine or vesicouterine pouch (Greek, -cele = hernia)

The material presented in these tables is contained in the book:
MedCharts Anatomy by Thomas R. Gest & Jaye Schlesinger
Published by ILOC, Inc., New York
Copyright © 1995, unauthorized use prohibited.
 The excellent editorial assistance of
Dr. Pat Tank, UAMS
is gratefully acknowledged.