Thorax + Abdomen muscles

Question 1

external intercostal action? origin and insertion?

Answer 1

action = elevates ribs
origin = inferior border of superior rib
insertion = superior border of inferior rib

Question 2

external oblique action? origin and insertion?

Answer 2

action = flexes vertebral column and compresses abdomen, lateral flexion and rotation of vertebral column
origin = superior border of inferior rib
insertion = inferior border of superior rib

Question 3

internal intercostal action? origin and insertion?

Answer 3

action = depresses ribs
origin = superior border of inferior rib
insertion = inferior border of superior rib

Question 4

internal oblique action?

Answer 4

flexes vertebral column and compresses abdomen, lateral flexion and rotation of vertebral column

Question 5

pectoralis major action? origin and insertion?

Answer 5

action = flexes, adducts, and medially rotates arm
origin = clavicle, ribs, sternum
insertion = humerus

Question 6

pectoralis minor action? origin and insertion?

Answer 6

action = protraction/abduction of scapula, depresses scapula
origin = ribs
insertion = coracoid process of scapula

Question 7

rectus abdominus action? origin and insertion?

Answer 7

action = flexes vertebral column and compresses abdominal wall
origin = pubis
insertion = xiphoid process of sternum, ribs 5-7

Question 8

serratus anterior action?

Answer 8

protraction of the scapula

Question 9

transverse abdominus action?

Answer 9

flexes vertebral column and compresses abdomen, lateral flexion of vertebral column

Question 10

linea alba action?

Answer 10

vertical fibrous strip that connects the left and right rectus sheaths

Question 11

rectus sheath action?

Answer 11

fibrous sleeve that encloses rectus abdominus