Perineum Flashcards
What is the perineum?
the region beneath the pelvic floor, between the thighs and above the skin
What are the borders of the perineum?
pubic symphysis, ischial tuberosities and the coccyx
What regions is the perineum divided into and what divides them?
the urogenital triangle and the anal triangle - divided by the line between the ischial tuberosities
What is the perineal membrane?
a membrane which further subdivides the urogenital triangle into a superficial perineal pouch and deep perineal pouch
What is the perineal body?
a thickening in the centre of the free edge of the perineal membrane - serves as an anchor for the sphincters associated with the termination of the urogenital tract and gastrointestinal tract
What are the transverse perineal muscles?
the 4 muscles (2 superficial, 2 deep) associated with the posterior margin of the perineal membrane
What is in the anal triangle?
the anal canal and the ischiorectal fossae (filled with fat)
What is the pudendal canal?
a canal in the fascia overlying obturator internus which contains the neurovascular bundle for the perineum
What delineates the upper 2/3rds and lower 1/3rd of the anus?
the pectinate line
What are the differences between the upper 2/3rds and lower 1/3rd of the anus?
the upper 2/3rds has mucosa and the lower 1/3rd has skin, the upper 2/3rds is supplied by the superior rectal artery and the lower 1/3rd is supplied by the inferior rectal artery, the upper 2/3rds drains into the portal system and the lower 1/3rd drains into the systemic and the upper 2/3rds has autonomic nerve supply and the lower 1/3rd has somatic
What is the internal anal sphincter?
a thickening in the smooth muscle wall which is under autonomic control
What are the 3 parts of the external anal sphincter?
the deep part which fuses with puborectalis, the superficial part which is anchored to the coccyx and perineal body and the subcutaneous part which is a flat circular band immediately beneath the skin
What is an episiotomy?
a controlled cut away from the perineal body to avoid tearing of the perineal body in child birth
What is located in the deep perineal pouch?
sphincters
What is located in the superficial perineal pouch?
anchor points of the external genitalia
What is the paraurethral gland?
a gland in the superficial perineal pouch of females which opens into the urethra
What is the greater vestibular gland?
a gland in the superficial perineal pouch of females which opens into the vagina
What are the four parts of the male urethra?
preprostatic part at the bladder neck, prostatic part through the prostate, membranous part which traverses the deep perineal pouch and the perineal membrane and the spongy part which traverses the penis
What is the internal urethral sphincter?
a sphincter at the neck of the bladder to prevent reflux of semen into the bladder- under autonomic control
Where is the bulbourethral gland located?
deep perineal pouch
What makes up the external male genitalia?
paired corpora cavernosa and a single corpus spongiosum
What muscles cover the penis?
ischiocavernosus and bulbospongiosus
What nerves fibres are carried via the pudendal nerve?
sensory, sympathetic and somatic motor of S2-4
What is the path of the pudendal nerve?
exits the pelvis with piriformis via the greater sciatic foramen, winds around the back of the ischial spine, goes back through the lesser sciatic foramen to the pudendal canal
