Muscles of Lower Pelvic bowl

Question 1

Deep Transverse Perineus

Answer 1

Origin Medial surface of the ischial ramus
Insertion Contralateral muscle and perinea! body/central tendinous point
Action Fixes and stabilizes the perinea! body/central tendinous point
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Internal pudenda! a.

Question 2

Superficial Transverse Perineus

Answer 2

Origin Medial surface of the ischial ramus
Insertion Contralateral muscle and perinea! body/central tendinous point
Action Fixes and stabilizes the perinea! body/central tendinous point
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Perinea! a.

Question 3

External Anal Sphincter

Answer 3

Origin Perinea! body or central tendinous point of the perineum
Insertion Encircles the anal canal; superficial fibers attach to the coccyx
Action Constricts the anal canal
Innervation Inferior rectal nerves (from pudenda! nerve)
Artery Inferior rectal a.

Question 4

Internal Anal Sphincter

Answer 4

Origin Encircles the anal canal
Insertion Encircles the anal canal
Action Constricts the anal canal
Innervation Parasympathetic fibers from S4
Artery Middle rectal a.

Question 5

Bulbospongiosus (female)

Answer 5

Origin Perinea I body and fascia of the bulb of the vestibule
Insertion Perinea I membrane and corpus cavernosum of the clitoris
Action Compresses the vestibular bulb and constricts the vaginal orifice
1lnnervation Deep branch of perinea! nerve from pudenda! nerve
Artery Perinea! a.

Question 6

Bulbospongiosus (male)

Answer 6

Origin Central tendinous point and the mid line raphe of the bulb of the penis
Insertion Perinea! membrane, dorsal surface of the corpus spongiosum, deep
penile fascia
Action Compresses the bulb of the penis, compresses the spongy urethra
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Perinea! a.

Question 7

Cremaster

Answer 7

Origin Inguinal ligament
Insertion Forms thin network of muscle fascicles around the spermatic cord and
testis (or around the distal portion of the round ligament of the uterus)
Action Elevates testis (not well developed in females)
Innervation Genital branch of the genitofemoral nerve
Artery Cremasteric a. (branch of inferior epigastric a.)

Question 8

Dartos

Answer 8

Origin Subcutaneous connective tissue of the scrotum and the penis (or labium
majus and clitoris)
Insertion Skin of the scrotum and penis (or labium majus and clitoris)
Action Elevates testis (tenses the skin of the pudenda! region in females)
Innervation Postganglionic sympathetic nerve fibers arriving via the ilioinguinal
nerve and the posterior scrotal nerve
Artery Cremasteric a., posterior scrotal (labial) a.

Question 9

Detrusor of Bladder

Answer 9

Origin Smooth muscle in the wall of the urinary bladder
Insertion Fascicles are arranged roughly in 3 layers
Action Compresses the urinary bladder
Innervation Parasympathetic nerve fibers from the pelvic splanchnic nerves (S2-S4)
Artery Superior and inferior vesical aa.

Question 10

lschiocavernosus

Answer 10

Origin Medial surface of the ischial tuberosity and ischiopubic ramus
Insertion Corpus cavernosum and crus of the penis/clitoris
Action Compresses the corpus cavernosum
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Perinea! a.

Question 11

Levator Prostate

Answer 11

Origin Posterior aspect of the pubis
Insertion Fa sci a of the prostate
Action Elevates the prostate
Innervation Branches of the ventral primary rami of S3-S4 spinal nerves
Artery Inferior gluteal a.

Question 12

Pubovaginalis

Answer 12

Origin Posterior aspect of the body of the pubis
Insertion Fascia of the vagina and the perinea! body
Action Draws the vagina forward and superiorly
Innervation Branches of the ventral primary rami of S3-S4 spinal nerves
Artery Inferior gluteal a.

Question 13

Sphincter Urethrae (females)

Answer 13

Origin Encircles the urethra
Insertion Encircles urethra and vagina; extends superiorly along the urethra as far
as the inferior surface of the bladder
Action Compresses urethra and vagina
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Internal pudenda! a.

Question 14

Sphincter Urethrae (males)

Answer 14

Origin Encircles the urethra
Insertion Encircles urethra, reaches lateral surface of prostate and inferior bladder
Action Compresses urethra
Innervation Deep branch of perinea! nerve from pudenda! nerve
Artery Internal pudenda! a.