Breast, pectoral, and axillary region

Question 1

Pectoralis major

Answer 1

Origin-Clavicular hear: anterior surface of medial clavicle. Sternocostal head: anterior surface of sternum and superior six costal cartilages
Insertion-lateral lip of intertubercular sulcus
Innervation-lateral and medial pectoral nerves
Action-Both heads: adduct and medially rotate humerous. Clavicluar head: flexes humerus
Sternocostal head: extends humerus from a flexed position

Question 2

Pectoralis minor

Answer 2

Origin-ribs 3-5 near their costal cartilages
Insertion-coracoid process
Innervation-medial pectoral nerve
Action-stabilizes scapula by drawing it inferiorly and anteriorly against thoracic wall

Question 3

Subclavius

Answer 3

Origin-junction of the 1st rib and costal cartilage
Insertion-inferior, middle clavicle
Innervation-nerve to subclavius
Action-anchors and depresses clavicle

Question 4

Serratus anterior

Answer 4

Origin-lateral parts of the 1st-8th ribs
Insertion-Anterior surface of medial border of scapula
Innervation-long thoracic nerve
Action-protracts scapular, holds scapula against the thoracic wall, superior rotation of the scapula