Muscles of the Pectoral Region

Question 1

pectoralis major

Answer 1

origin: clavicle, sternum and ribs 1-6
insertion: crest of the greater tubercle of the humerus
innervation: medial and lateral pectoral NN
action: medial rot., addu. and flex. of the arm

Question 2

pectoralis minor

Answer 2

origin: ribs 3-5
insertion: coracoid process of the scapula
innervation: medial pectoral nerve
action: protraction of the scapula

Question 3

serratus anterior

Answer 3

origin: ribs 1-9
insertion: medial border of the scapula, costal surface
innervation: long thoracic N. (C5-C7)
action: protraction and superior rotation of the lateral angle of the scapula; holds scapula against the dorsal trunk