Perineal Anatomy PDF

Perineal Anatomy Gabin: [email protected]  The Perineum The perineum is a shallow compartment bounded by the pelvic outlet and separated from the pelvic cavity via the diaphragmatic fascia which covers the inferior aspect of the pelvic diaphragm This...

Perineal Anatomy Gabin: [email protected]  The Perineum The perineum is a shallow compartment bounded by the pelvic outlet and separated from the pelvic cavity via the diaphragmatic fascia which covers the inferior aspect of the pelvic diaphragm This diamond-shaped structure can be separated into an anterior and posterior triangle Urogenital triangle (anterior) Covered by a triangular structure known as the urogenital diaphragm (in the deep perineal pouch) ○ It is enclosed by a fascia (perineal membrane/ inferior fascia of the urogenital diaphragm) This membrane contains the urogenital hiatus which transmits the urethra and vagina The perineal membrane also divides the superficial pouch from the deep pouch Anal triangle (posterior) Contains the rectal hiatus which transmits the anal canal and is surrounded by the ischioanal fossae Urogenital Triangle Superficial Perineal Pouch Potential space between the membranous layer of superficial fascia (perineal fascia) inferiorly and the perineal membrane (inferior diaphragmatic fascia) superiorly Bounded laterally by the ischiopubic rami Contents (male) Contents (female) Root (bulb and crura) of the penis and Clitoris and associated muscles associated muscles (bulbospongiosus and (ischiocavernosus) ischiocavernosus) Bulbs of the vestibule and surrounding Proximal (bulbous) part of the spongy muscle (bulbospongiosus) urethra Greater vestibular glands Superficial transverse perineal muscles Superficial transverse perineal muscles Deep perineal branches of the internal pudendal vessels and pudendal nerves  Male and Female Genitalia Male Female Description Muscle covering Corpus Glans clitoris Distal end of spongy erectile tissue spongiosum and In males, this contains the spongy urethra glans penis Bulb of the penis Vestibular bulb 2 elongated masses of spongy erectile tissue lateral Bulbospongiosus to the proximal urethra During the response to sexual arousal, the bulbs become engorged with blood causing an erection Crus of penis Crus of clitoris Distal extension of corpora cavernosa - region following Ischiocavernosus the lateral separation of corpora cavernosa Helps flex the anus ○ Erectile tissue Stabilises the erect penis/ tenses the vagina in ○ 2 crura are lateral to the bulb of the penis/ orgasm vestibular bulb Pelvic floor exercises can tone this muscle In males, it compresses the crus, retarding the return of blood in veins to help maintain erections Corpora Corpora cavernosa Sponge-like regions of erectile tissue that contains most cavernosa penis clitoris of the blood in erections Bulbourethral Greater vestibular Secretes lubricating mucous (females) and seminal fluid glands glands (males) Urethral meatus Urethral meatus External opening of the urethra/ external urethral orifice Scrotus Labia majora Skin covering external genitals Deep Perineal Pouch Bounded inferiorly by the inferior diaphragmatic fascia (perineal membrane) and superiorly by the superior diaphragmatic fascia Contents ○ Urogenital diaphragm - triangular muscle which contains the external urethral sphincter Male external urethral sphincter Only the inferior part of the muscle encloses the urethra The superior part assists in investing the prostatic urethra Trough-like fibres which ascend to the neck of the bladder Female external urethral sphincter Not trough-shaped Layers of the Abdomen, Perineum, Scrotum and Penis Layers of the Abdomen, Perineum, Scrotum and Penis Abdomen Perineum Scrotum Penis Skin Skin Skin Camper’s fascia Fatty layer of superficial fascia Scarpa’s fascia Colle fascia Dartos m. (membranous layer of superficial fascia) External oblique m. Deep perineal External spermatic Buck’s fascia pouch? fascia Internal oblique m. Pelvic floor m.? Cremaster m. Transversalis fascia Internal spermatic fascia