Upper Limb to Thoracic Wall

Question 1

Pectoralis Major

Answer 1

Origin: clavicle, sternum, and upper six costal cartilages
Insertion: lateral lip of bicipital groove of humerus
Nerve: medial and lateral pectoral nerves from brachial plexus
Action: adducts arm and rotates it medially; clavicular fibers also flex arm

Question 2

Pectoralis Minor

Answer 2

Origin: third, fourth, and fifth ribs
Insertion: coracoid process of scapula
Nerve: medial pectoral nerve from brachial plexus
Action: depresses point of the shoulder; if scapula is fixed, it elevates the ribs of origin

Question 3

Subclavius

Answer 3

Origin: first costal cartilage
Insertion: clavicle
Nerve: nerve to subclavius from upper trunk of brachial plexus
Action: depresses the clavicle and steadies this bone during movements of the shoulder girdle

Question 4

Serratus Anterior

Answer 4

Origin: upper eight ribs
Insertion: medial border and inferior angle of scapula
Nerve: long thoracic nerve
Action: draws the scapula forward around the thoracic wall; rotates scapula