MOINA of Muscles Connecting the Upper Limb to the 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

adducts arm and rotates it medially; clavicular fibers also flex arm (FAdIr)

Question 2

pectoralis minor

Answer 2

origin: third, fourth, and fifth ribs
insertion: coracoid process of scapula

nerve: medial pectoral nerve from brachial plexus

depresses point of shoulder; if the scapula is fixed, it elevates the ribs of origin (accessory muscle for breathing)

Question 3

subclavius

Answer 3

origin: first costal cartilage
insertion: clavicle

nerve: nerve to subclavius from upper trunk of brachial plexus

depresses the clavicle and steadies this bone during movements of the shoulder girdle (most commonly Fx bone in the body)

Question 4

serratus anterior

Answer 4

origin: upper eight ribs
insertion: medial border and inferior angle of scapula

nerve: long thoracic nerve

draws scapula forward around the thoracic wall; rotates scapula (“Boxer’s Muscle”)