What are the boundaries of the perineum?
Anterior: pubic symphysis; Posterior: tip of coccyx; Lateral: ischial tuberosities; Superior: pelvic diaphragm; Inferior: skin.
What are the divisions of the perineum?
Urogenital triangle (anterior) and Anal triangle (posterior).
What are the contents of the urogenital triangle?
Male: penis, scrotum, superficial/deep perineal muscles, urethra. Female: clitoris, vestibule, labia, superficial perineal muscles, urethra, vaginal opening.
What are the contents of the anal triangle?
Anal canal, ischioanal fat, pudendal canal, inferior rectal vessels and nerves.
What are the differences between male and female perineum?
Male: penis, scrotum, strong perineal body; Superficial/deep muscles in urogenital triangle. Female: clitoris, vestibule, labia, thicker perineal body; similar muscles with vestibular bulbs and greater vestibular glands.
What are the attachments of the perineal membrane?
Between ischiopubic rami.
What are the relations of the perineal membrane?
Superior: deep perineal pouch; Inferior: superficial perineal pouch; Anterior: attached to pubic arch.
What are the perineal pouches and their formation?
Superficial perineal pouch: between perineal membrane and membranous fascia. Deep perineal pouch: between perineal membrane and pelvic diaphragm.
What are the contents of the superficial perineal pouch?
Male: bulbospongiosus, ischiocavernosus, superficial transverse perineal muscles, root of penis, bulb of penis, crura, superficial perineal vessels/nerves. Female: same muscles, bulbs of vestibule, crura of clitoris, greater vestibular glands.
What are the contents of the deep perineal pouch?
Male: deep transverse perineal muscles, external urethral sphincter, bulbourethral glands, dorsal neurovasculature of penis. Female: external urethral sphincter, dorsal neurovasculature of clitoris.
List the muscles of the perineum with their attachments, actions, and nerve supply.
Bulbospongiosus: perineal body → bulb/root of penis or vestibule; compress bulb, maintain erection, assist urination/ejaculation; pudendal nerve.
Ischiocavernosus: ischial tuberosity → corpus cavernosum; maintain erection; pudendal nerve.
Superficial transverse perineal: ischial tuberosity → perineal body; stabilize perineal body; pudendal nerve.
Deep transverse perineal: ischial rami → perineal body; stabilize perineal body; pudendal nerve.
External urethral sphincter: surrounds urethra; voluntary urination control; pudendal nerve.
Levator ani: pubis/ischial spine → coccyx/anococcygeal ligament; support pelvic viscera; S4 + pudendal nerve.
Describe the gross anatomy of the penis.
Root: crura (attached to ischiopubic rami), bulb (attached to perineal membrane). Body: shaft with two corpora cavernosa and one corpus spongiosum. Glans: distal expansion of corpus spongiosum.
What is the arterial supply of the penis?
Dorsal artery of penis, deep artery of penis, artery of bulb.
What is the venous drainage of the penis?
Deep dorsal vein → prostatic venous plexus; Superficial veins → external pudendal vein.
What is the nerve supply of the penis?
Dorsal nerve of penis (pudendal nerve); autonomic fibers for erection.
Which muscles form the perineal body and their attachments/nerve supply?
Bulbospongiosus: perineal body → bulb of penis or vestibule; pudendal nerve. Superficial transverse perineal: ischial tuberosity → perineal body; pudendal nerve. Deep transverse perineal: ischial rami → perineal body; pudendal nerve. External anal sphincter (part): perineal body → anus; pudendal nerve.
