Unit 2 innervation/action of muscles

Question 1

Intercostal (external) m

Answer 1

elevation of the ribs, intercostal nerve

Question 2

Intercostal (internal) m

Answer 2

depression of the ribs, intercostal nerve

Question 3

Transversus thoracis

Answer 3

depress ribs, intercostal nerves

Question 4

Cremaster

Answer 4

elevation of testis, genitofemoral nerve

Question 5

Diaphragm

Answer 5

inspiration (negative thoracic pressure by inferior displacement), phrenic nerve

Question 6

External oblique

Answer 6

flexion and rotation of the trunk, compression of the abdominal cavity, ventral rami T7-12

Question 7

Internal oblique

Answer 7

flexion and rotation of the trunk, compression of the abdominal cavity, innervated by the lower thoracic and L1 ventral rami

Question 8

Quadratus Lumborum

Answer 8

extension and lateral flexion of the trunk, fixes 12th rib during respiration, ventral rami T12-L3

Question 9

Rectus abdominis

Answer 9

flexion of trunk and compression of abdominal cavity, lower thoracic ventral rami

Question 10

Transversus abdominis

Answer 10

compression of the abdominal cavity, lower thoracic and L1 ventral rami

Question 11

Coccygeus

Answer 11

supports and compresses the posterior pelvic floor, ventral rami S4-5

Question 12

Levator ani

Answer 12

supports pelvic viscera, compresses rectum and vagina. pudendal nerve (inferior rectal branches) and S4.

Question 13

Bulbospongiosus

Answer 13

In male, empties urethra, maintains erection, and contracts during ejaculation; in female constricts vaginal orifice and contributes to erection of clitoris. Innervated by perineal branch of pudendal nerve

Question 14

ischiocavernosus

Answer 14

compresses crus during erection. perineal branch of the pudendal nerve

Question 15

Sphincter ani externus

Answer 15

closes anal canal and fixes perineal body. inferior rectal branch of pudendal nerve

Question 16

Sphincter urethrae

Answer 16

compresses urethra, perineal branch of pudendal nerve

Question 17

compressor urethrae

Answer 17

compresses urethra, perineal branch of pudendal nerve

Question 18

sphincter urethrovaginalis

Answer 18

compresses urethra and vagina, perineal branch of pudendal nerve

Question 19

deep transverse perineus

Answer 19

fixes perineal body, perineal branch of pudendal nerve

Question 20

superficial transverse perineus

Answer 20

fixes perineal body, perineal branch of the pudendal nerve

Question 21

sensory/post symp to proximomedial thigh, root of the penis/scrotum or mons pubis and labia majora, muscles of the anterior abdominal wall

Answer 21

Ilioinguinal nerve

Question 22

Muscles of anterior abdominal wall

Answer 22

iliohypogastric, ilioinguinal

Question 23

skin overlying labium majorum/scrotum, cremaster muscle

Answer 23

Specifically, the genital branch of the genitofemoral nerve (L1-L2)

Question 24

skin overlying the femoral triangle

Answer 24

the Femoral branch of the genitofemoral nerve (only sensory/post-symp)

Question 25

Psoas, quadratus lumborum muscles

Answer 25

Muscular branches off the lumbar ventral rami