Part 18: Male Urogenital Region Flashcards
What is the perineal membrane?
unyielding sheet of fibrous tissue attached to both ischiopubic rami from just behind subpubic angle to just anterior to ischial tuberosities. Anteriorly forms transverse perineal ligament. Posteriorly attached to superficial perineal fascia which fuses with perineal body
What is the deep perineal pouch?
Space between perineal membrane (deep) and the loose pelvic fascia above urogenital diaphragm (superior fascia of UG diaphragm)
What is the urogenital diaphragm?
Muscle mass superior (deep) to perineal membrane.
Consists of sphincter urethrae (external urethral sphincter) and paired deep transverse perineal muscles.
Where are the bulbourethral glands (of Cowper) located?
Each side of membranous urethra in deep perineal pouch. Ducts pierce perineal membrane to open into penile urethra. Contribute small amount to seminal fluid.
What is the superficial perineal pouch?
Area between superficial perineal fascia (of Colles) and perineal membrane.
What are the margins of Colles fascia?
Front - pubic bone - continues up into AAW as scarpa’s fascia.
Projected into scrotal and penile expansions.
Therefore theoretically ruptures penile urethra - urine could extent all the way up AAW
How is the penis attached to the pelvis?
Root of penis attached to perineal membrane, consisting of central bulb and lateral crus
What are the main constituents of the penis?
Lateral crus: Corpus cavernosum (bound side by side), suspended from the PS via the suspensory ligament.
Central bulb: Corpus spongiosum, accepts urethra, arteries and ducts of bulbourethral glands
What is the surrounding fascia of the penis?
Tunica albuginea surround each corpus. This is surrounded by Buck’s fascia (continuation of scarpa’s fascia)
Within Buck’s fascia lie what vessels and nerves?
Dorsal arteries and Dorsal nerves
Dorsal Vein
Superficial to Bucks fascia is superficial dorsal vein and lymphatics
What is the blood supply to the penis?
3 pairs of arteries - all branches from internal pudendal
- branch to bulb (supplies CS and glands)
- dorsal arteries supply skin, fascia, glans - anastomoses with bulb artery
- Deep artery supplies CC - closed system which is essential to erection
What is the venous drainage of penis?
Mainly though deep dorsal vein, other small veins pass with arteries. Passes above perineal membrane (anterior to transverse perineal ligament) to vesicoprostatic plexus
What is lymphatic drainage of penis?
Skin - to superfical inguinal nodes
CS + CC - to deep inguinal nodes
What is the nerve supply of penis?
Pudendal nerves via posterior scrotal and dorsal nerves (mainly S2)
Sympathetic nerves essential for ejaculation are derived from L1 of spinal cord via superior and inferior hypogastric plexus
Pelvic splanchnic supplies PSNS supply to all corpora to allow increased blood flow for erection
What are the superficial perineal muscles?
Bulbospongiosus (AKA compressor urethrae - from perineal body/midline raphe forwards and laterally over bulb to perineal membrane - helps empty urethra
Ischiocavernosus - posterior part perineal membrane/ramus ischium to upper surfaee of CC - supports erect penis
Superficial transverse perineal muscle - perineal membrane to perineal body(helps stabilise body)