Superficial Thoracic Wall Muscles

Question 1

Pectoralis Major

Answer 1

PA:
med 1/2 clavicle along ant portion, sternum along 1/2 ant surface, 1-7 costal cartilage, sternal end of 6th rib & aponeurosis of EAO.

DA:
Lat lip of bicipital groove

Inn:
Med and lat pectoral
Calvicular fibers: C5,6
Sternal fibers: C6-T1

Actions:
OC: Humerus adduction and med rot
clavicular fibers: flex an extended arm
sternal fibers: extend a flexed arm

CC:draws trunk upward and forward.

Question 2

Pectoralis Minor

Answer 2

PA:
Ribs 3-5 along upper margins and outer surfaces near costal cartilage, fascia over adjoining ext intercostal mm.

DA:
Coracoid process along med border and upper surface.

Inn:
med and lat pectoral C5-T1

Action:
Scapular depression (downward rot and inf slide), assists with protraction (IR of and lat slide of scapula)

Question 3

Subclavius

Answer 3

PA:
1st rib at junction of rib and its costal cartilage

DA:
Groove on middle 1/3 of clavicles inferior surface

Inn: Nerve to subclavius C5,6

Action:
OC: Approximating the clavicle towards the manubrium during violent extremity motions such as throwing or hitting. Produces clavicular depression and protraction.

CC:
Secondary mm of respiration.

Question 4

Serratus Anterior

Answer 4

PA:
Upper 8 ribs along ext surfaces and sup borders, & to fascia of adjoining intercostal mm.

DA: Scapula along med border of ant surface

Inn:
Long thoracic C5,6,7

Actions:
Scapular upward rotation, lat slide, prevents scapular winging