Anatomy of the Muscles of the Pelvis and Perineum

Muscle	Origin	Insertion	Action	Innervation	Artery	Notes
anal sphincter, external	perineal body or central tendinous point of the perineum	encircles the anal canal; superficial fibres attach to the coccyx	constricts the anal canal	inferior rectal nerves (from the pudendal nerve)	inferior rectal a.	skeletal (voluntary) muscle, as contrasted with sphincter ani internus, which is smooth (involuntary) muscle; the external anal sphincter is considered part of the pelvic diaphragm
anal sphincter, internal	encircles the anal canal	encircles the anal canal	constricts the anal canal	parasympathetic fibers from S4	middle rectal a.	smooth muscle (involuntary), as contrasted with sphincter ani externus, which is skeletal muscle (voluntary)
bulbospongiosus, in female	perineal body and fascia of the bulb of the vestibule	perineal membrane and corpus cavernosum of the clitoris	compresses the vestibular bulb and constricts the vaginal orifice	deep branch of the perineal nerve (from pudendal nerve)	perineal a.	skeletal muscle
bulbospongiosus, in male	central tendinous point and the midline raphe on the bulb of the penis	perineal membrane, dorsal surface of the corpus spongiosum, deep penile fascia	compresses the bulb of the penis, compresses the spongy urethra	deep branch of the perineal nerve (from pudendal nerve)	perineal a.	expels the last drops of urine from urethra; expels semen during ejaculation
coccygeus	ischial spine	side of the coccyx and lower sacrum	elevates the pelvic floor	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	coccygeus and levator ani combined form the pelvic diaphragm
deep transverse perineus	medial surface of the ischial ramus	contralateral muscle and perineal body/central tendinous point	fixes and stabilizes the perineal body/central tendinous point	deep branch of perineal nerve from pudendal nerve	internal pudendal a.	superficial and deep transverse perineus muscles are separated by the perineal membrane
detruser of bladder	smooth muscle in the wall of the urinary bladder	fascicles are arranged roughly in three layers	compresses the urinary bladder	parasympathetic nerve fibers from the pelvic splanchnic nerves (S2-S4 spinal cord levels)	superior and inferior vesical aa.	muscles in the neck of bladder must contract and cause the internal urethral orifice to open before the detruser muscle can void the bladder (Latin, detruser = to push down)
iliococcygeus	arcus tendineus levator ani and the ischial spine	anococcygeal raphe and the coccyx	elevates the pelvic floor	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	the combination of puborectalis, pubococcygeus and iliococcygeus is called the levator ani m.
ischiocavernosus	medial surface of the ischial tuberosity and the ischiopubic ramus	corpus cavernosum and crus of the penis/clitoris	compresses the corpus cavernosum	deep branch of the perineal nerve (from pudendal nerve)	perineal a.	ischiocavernosus m. is closely applied to the surface of the crus penis/clitoris
levator ani	posterior surface of the body of the pubis, fascia of the obturator internus m. (arcus tendineus levator ani), ischial spine	anococcygeal raphe and coccyx	elevates the pelvic floor	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	the combination of puborectalis, pubococcygeus & iliococcygeus is the levator ani m.; coccygeus and levator ani combined form the pelvic diaphragm (Latin, levator = to lift)
levator prostatae	posterior aspect of the pubis	fascia of the prostate	elevates the prostate	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	levator prostatae is part of the puborectalis m. (Latin, levator = to lift)
pubococcygeus	posterior aspect of the superior pubic ramis	coccyx	elevates the pelvic floor	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	the combination of puborectalis, pubococcygeus and iliococcygeus is called the levator ani m.
puborectalis	posterior aspect of the body of the pubis	unites with the puborectalis m. of other side posterior to the rectum	draws the distal rectum forward and superiorly; aids in voluntary retention of feces	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.	the combination of puborectalis, pubococcygeus and iliococcygeus is called the levator ani m.
pubovaginalis	posterior aspect of the body of the pubis	fascia of the vagina and perineal body	draws the vagina forward and superiorly	branches of the ventral primary rami of spinal nerves S3-S4	inferior gluteal a.
sphincter ani externus	perineal body or central tendinous point of the perineum	encircles the anal canal; superficial fibers attach to the coccyx	constricts the anal canal	inferior rectal nerves (from the pudendal nerve)	inferior rectal a.	skeletal (voluntary) muscle, as contrasted with sphincter ani internus, which is smooth (involuntary) muscle; the external anal sphincter is considered part of the pelvic diaphragm
sphincter ani internus	encircles the anal canal	encircles the anal canal	constricts the anal canal	parasympathetic fibers from S4	middle rectal a.	smooth muscle (involuntary), as contrasted with sphincter ani externus, which is skeletal muscle (voluntary)
sphincter urethrae, in female	encircles the urethra	encircles urethra and vagina; extends superiorly along the urethra as far as the inferior surface of the bladder	compresses urethra and vagina	deep branch of perineal nerve from pudendal nerve	internal pudendal a.	skeletal muscle
sphincter urethrae, in male	encircles the urethra	encircles urethra, reaches lateral surface of prostate and inferior bladder	compresses urethra	deep branch of perineal nerve from pudendal nerve	internal pudendal a.	skeletal muscle
superficial transverse perineus	medial surface of the ischial ramus	contralateral muscle and the perineal body/central tendinous point	fixes and stabilizes perineal body/central tendinous point	deep branch of perineal nerve from pudendal nerve	perineal a.	superficial and deep transverse perineus muscles are separated by the perineal membrane
transverse perineus, deep	medial surface of the ischial ramus	contralateral muscle and perineal body/central tendinous point	fixes and stabilizes the perineal body/central tendinous point	deep branch of perineal nerve from pudendal nerve	internal pudendal a.	superficial and deep transverse perineus muscles are separated by the perineal membrane
transverse perineus, superficial	medial surface of the ischial ramus	contralateral muscle and the perineal body/central tendinous point	fixes and stabilizes perineal body/central tendinous point	deep branch of perineal nerve from pudendal nerve	perineal a.	superficial and deep transverse perineus muscles are separated by the perineal membrane