10- Muscles o the Anterior Thorax

Question 1

Pectoralis Minor

Answer 1

Flat, thin muscle directly beneath and obscured by pectoralis major.

Draws scapula forward and downward; with scapula fixed, draws rib cage superiorly.

Question 2

Serratus Anetior

Answer 2

Deep to scapula; beneath and inferior to pectoral muscles on lateral rib cage; forms medial wall of axilla; origins have serrate appearance. Paralysis results in winging of vertebral border of scapula away from chest wall, making arm elevation impossible.

Prime mover to protract and hold scapula against chest wall; rotates scapula so that its inferior angle moves laterally and upward; raises point of shoulder; important role in abduction and raising of arm and in horizontal arm movements. called boxers muscle.

Question 3

Subclavius

Answer 3

Small cylindrical muscle extending from rib 1 to clavicle.

Helps stabilize and depress pectoral girdle.