Serratus Posterior Inferior/ Superior

Question 1

Name action, origin, insertion and nerve for serratus anterior

Answer 1

O: external surfaces of upper 8-9 ribs
I: anterior surface of medial border of the scapula
A: origin fixed (4)- DEPRESS scapula, UPWARDLY ROTATES scapula, ABDUCT the scapula, HOLD medial border of the scapula against the ribs
With scapula fixed- may ELEVATE thorax during forced inhalation.
C5,6,7,8

Question 2

What are the action, origin, insertion and nerve for serratus posterior superior

Answer 2

A: elevate the rings during inhalation
O: spinous processes of C7-T3
I: posterior surface of 2nd through 5th ribs
N: T1,2,3,4

Question 3

What are the action, origin, insertion and nerve for serratus posterior inferior

Answer 3

A: Depress the rib during exhalation
O: spinous processes of T12-L3
I: posterior surface of 9th through 12th ribs
T9,10,11,12