L 27 Genital System & Perineum – Key Vocabulary

A comprehensive set of vocabulary flashcards covering anatomical structures, muscles, glands, vessels, and neural elements discussed in the lecture on the genital system and perineum.

Genital system

Collective term for external genitalia, gonads, and genital ducts housed in the pelvic cavity and perineum.

External genitalia

Visible reproductive structures—penis & scrotum in males, vulva in females—located in the perineum.

Gonads

Primary sex organs (testes or ovaries) that produce gametes and sex hormones.

Genital ducts

Tubes that transport gametes or secretions (e.g., ductus deferens, uterine tubes, uterus, vagina).

Perineum

Region inferior to the pelvic diaphragm containing external genitalia, terminal GU & GI tracts, glands, muscles, and neurovasculature.

Pelvic diaphragm

Muscular floor of the pelvic cavity; superior boundary of the perineum.

Ischial tuberosities

Bony prominences whose line divides the perineum into anal and urogenital triangles.

Anal triangle

Posterior perineal subdivision containing the anus, anal canal, external anal sphincter, and ischioanal fossae.

Urogenital triangle

Anterior perineal subdivision housing the urethral and genital structures; divided into superficial and deep spaces.

Perineal membrane

Fibrous sheet spanning the urogenital triangle; anchors erectile tissues and is pierced by urethra (and vagina).

Perineal body

Midline musculo-fibrous mass where multiple perineal muscles, the external anal sphincter, and puborectalis meet.

Ischioanal fossa

Fat-filled, wedge-shaped space lateral to anal canal that allows expansion of the canal and communicates with deep perineal space.

Deep perineal space

Compartment between pelvic diaphragm and perineal membrane containing deep perineal muscles, bulbourethral glands (♂), and urethra/vagina segments.

Superficial perineal space

Compartment inferior to the perineal membrane that contains erectile bodies, superficial perineal muscles, neurovasculature, and glands.

Colles fascia

Membranous layer of superficial fascia in the perineum; continuous with Scarpa fascia and dartos fascia, creating a closed superficial pouch.

External anal sphincter

Voluntary skeletal muscle encircling anal canal; maintains continence; supplied by inferior rectal nerves (pudendal, S2-S4).

Deep transverse perineal muscle

Deep perineal muscle spanning ischiopubic rami to perineal body/external anal sphincter; supports pelvic floor.

External urethral sphincter

Skeletal muscle encircling urethra (plus prostate/vagina) to prevent urination; located in deep perineal space.

Bulbospongiosus muscle

Superficial muscle covering bulb of penis or bulb of vestibule; aids ejaculation/urethral emptying in ♂ and vaginal constriction in ♀.

Ischiocavernosus muscle

Superficial muscle overlying penile or clitoral crura; compresses erectile tissue to maintain erection/engorgement.

Superficial transverse perineal muscle

Superficial muscle from ischiopubic rami to perineal body; stabilizes pelvic floor and perineal body.

Erectile body

Cavernous tissue cylinder that fills with blood during sexual arousal (e.g., corpus spongiosum, corpora cavernosa).

Corpus spongiosum

Single ventral erectile body of penis transmitting spongy urethra; expands distally as glans.

Corpora cavernosa

Paired dorsal erectile bodies of penis or clitoris responsible for most rigidity during erection.

Crus (penis/clitoris)

Proximal, diverging part of each corpus cavernosum attached to ischiopubic ramus and perineal membrane.

Bulb of penis

Proximal enlargement of corpus spongiosum attached to perineal membrane; pierced by urethra.

Bulbs of vestibule

Paired erectile bodies lateral to vaginal vestibule that engorge during arousal and constrict vaginal/urethral orifices.

Glans (penis/clitoris)

Distal expansion of corpus spongiosum or corporal tissue; houses external urethral orifice in ♂.

Corona of glans

Prominent rim at base of the glans penis.

Prepuce (foreskin)

Fold of skin covering the penile glans; in females, labia minora unite to form clitoral prepuce.

Scrotum

Skin-covered sac derived from anterior abdominal wall that encloses testes and spermatic cords.

Dartos muscle

Smooth muscle layer in scrotal wall; contraction wrinkles skin to reduce heat loss and warm testes.

Vulva

Collective term for female external genitalia (mons pubis, labia majora & minora, clitoris, vestibule).

Mons pubis

Fat pad over pubic symphysis in females.

Labia majora

Paired fatty skin folds forming lateral boundaries of vulva; homologous to scrotum.

Labia minora

Paired thin folds medial to labia majora; join anteriorly as clitoral prepuce.

Clitoris

Erectile organ composed of two fused corpora cavernosa and a glans; homologous to penile body/glans.

Vestibule (vagina)

Space between labia minora containing external urethral and vaginal orifices and vestibular gland ducts.

Greater vestibular (Bartholin) glands

Mucus-secreting glands in superficial pouch posterolateral to vaginal orifice; lubricate vestibule.

Testis

Male gonad producing sperm and testosterone; supplied by testicular artery from abdominal aorta.

Seminiferous tubules

Highly coiled tubes inside testes where spermatogenesis occurs.

Epididymis

Coiled duct on testis’ posterior surface for sperm maturation and storage; leads to ductus deferens.

Ductus (vas) deferens

Thick-walled muscular tube conveying sperm from epididymis to ejaculatory duct; site ligated in vasectomy.

Spermatic cord

Bundle of ductus deferens, testicular vessels, lymphatics, and nerves enclosed in abdominal wall fascia; traverses inguinal canal.

Seminal vesicle

Paired gland posterior to bladder that adds fructose-rich alkaline fluid to semen.

Ejaculatory duct

Duct formed by union of ductus deferens and seminal vesicle duct; traverses prostate to open into prostatic urethra.

Prostate gland

Walnut-sized gland encircling prostatic urethra; secretes enzyme-rich alkaline fluid; enlargement can obstruct urine flow.

Bulbourethral (Cowper) glands

Paired glands in deep perineal space; secrete pre-ejaculate alkaline mucus into urethra.

Ovary

Female gonad producing oocytes and hormones; suspended by suspensory ligament containing ovarian vessels.

Suspensory ligament of ovary

Peritoneal fold conveying ovarian vessels and nerves from pelvic wall to ovary.

Uterine (fallopian) tube

Muscular duct transporting oocyte from ovary to uterine cavity; site of fertilization.

Fimbriae

Finger-like projections around abdominal ostium of uterine tube that sweep oocyte into tube.

Uterus

Hollow muscular organ that receives, retains, and supports embryo/fetus; normally anteverted and anteflexed.

Fundus (uterus)

Rounded superior portion of uterine body above uterine tube openings; measured to gauge pregnancy age.

Cervix

Inferior tubular third of uterus containing cervical canal and internal/external os.

Internal os

Superior opening of cervical canal into uterine cavity.

External os

Inferior opening of cervical canal into vagina; site sampled in Pap test.

Endometrium

Inner mucosal uterine layer that partially sheds during menstruation and implants blastocyst.

Myometrium

Middle smooth-muscle layer of uterus that contracts during menstruation and childbirth.

Perimetrium

Outer serosal (peritoneal) covering of uterus.

Round ligament of uterus

Fibrous cord from uterus through inguinal canal to labia majora; maintains anteverted uterine position.

Broad ligament

Double fold of peritoneum draped over uterus, uterine tubes, and ovaries; provides support and conduit for vessels.

Vagina

Fibromuscular tube extending from cervix to vestibule; female copulatory organ and part of birth canal.

Internal pudendal artery

Branch of internal iliac artery supplying perineum and external genitalia (inferior rectal, perineal, dorsal penile/clitoral branches).

Pudendal nerve

Somatic nerve (S2-S4) providing motor to perineal muscles and sensory to perineum & external genitalia.

Inferior rectal nerve

Pudendal branch supplying external anal sphincter and skin around anal canal.

Pelvic pain line

Conceptual line dividing visceral pain pathways: organs touching peritoneum send pain with sympathetics (T12-L2/3); subperitoneal organs send with parasympathetics (S2-S4).

Pelvic splanchnic nerves

Parasympathetic fibers (S2-S4) causing vasodilation in erectile tissues and contraction of bladder/rectum.

Lumbar & sacral splanchnic nerves

Sympathetic fibers (T11-L2/3) that mediate vasoconstriction, internal sphincter closure, and emission/ejaculation.

Ischiopubic ramus

Bony ridge of pubis and ischium serving as attachment for crura, perineal membrane, and multiple perineal muscles.

Ischioanal fossa communication

Posteriorly continuous with contralateral fossa and anteriorly with deep perineal space, permitting spread of infection.