--- module: 079-03 language: en chapter: 79 title: "Pelvic, Perineal, Reproductive, and Urinary Anatomy" module_title: "Perineum, external genitalia, internal reproductive organs, and sexual anatomy" source_sha256: 6c96cbcd6bffa7e3277b7c45ae06b49fc70ceb7552f9860fb53e19db3067ad1d --- # Perineum, genitalia, and reproductive organs ## Perineal triangles and pouches ### Diamond from symphysis to coccyx ### Intertuberous line divides two triangles ### Perineal membrane spans pubic arch ### Superficial pouch: genital roots, muscles #### Greater vestibular glands when present ### Deep pouch: external urethral sphincter #### Bulbourethral glands in male anatomy ### Ischioanal fossae: fat permits anal expansion #### Pudendal canal in obturator fascia #### Infection crosses behind anal canal ## Perineal fascia and spread ### Membranous fascia continues with Scarpa, dartos #### Attachment below inguinal ligament spares thigh ### Spongy urethral rupture #### Urine to scrotum, penis, abdominal wall #### Not freely into thighs or anal triangle ### Membranous or bladder injury: deep planes ### Necrotising infection spreads along planes ## Erectile tissue and control ### Vascular spaces within tunica ### Cavernosa form crura on ischiopubic rami ### Spongiosum surrounds spongy urethra ### Clitoral corpora, vestibular bulbs ### Ischiocavernosus reduces venous outflow ### Bulbospongiosus: ejaculation, vaginal constriction ### Parasympathetic cavernous nerves #### Nitric oxide dilates arteries, erection ### Sympathetic: emission, detumescence ### Dorsal nerve somatic, autonomic nerves deeper ## Testes, cord, and ducts ### Descent through inguinal canal #### Coverings from abdominal wall layers #### Tunica vaginalis from processus vaginalis ### Tubules to rete, epididymis, ductus ### Cord contents #### Ilioinguinal nerve outside coverings ### Arteries from aorta #### Left vein to left renal vein #### Lymph to para-aortic nodes ### Ductus crosses ureter, joins seminal duct ## Prostate and accessory glands ### Surrounds proximal urethra below bladder ### Peripheral, central, transitional, anterior zones #### Carcinoma mostly peripheral #### Benign enlargement transitional ### Ejaculatory ducts open near colliculus ### Venous plexus to vertebral plexus ### Seminal glands: fructose, no sperm storage ## Ovaries, tubes, uterus, vagina ### Ovary in ovarian fossa, position varies #### Suspensory ligament carries ovarian vessels #### Ovarian vessels and lymph to aorta ### Tube: fimbriae, ampulla, isthmus #### Fertilisation commonly in ampulla #### Impaired transport: ectopic pregnancy ### Uterus commonly anteverted, anteflexed ### Broad ligament not main support #### Cardinal, uterosacral, floor support ### Uterine artery crosses above ureter ### Posterior fornix deepest ### Lower vagina somatic, upper autonomic ## External genitalia and glands ### Vulva: labia, clitoris, vestibule, glands #### Size and pigmentation vary widely ### Penis: paired cavernosa, ventral spongiosum #### Deep dorsal vein to prostatic plexus ### Cremaster via genitofemoral motor fibres ### Temperature: skin, dartos, pampiniform exchange ## Childbirth, surgery, and pain ### Birth stretches floor and perineal body #### Nerves, levator, sphincter may tear #### Repair identifies sphincter, rectal injury ### Hysterectomy risks ureter ### Prostate, rectal surgery risk cavernous nerves ### Node dissection risks obturator nerve ### Perineal pain has many sources #### Localise by organ, not gender