HN210 Study Guide - Midterm Guide: Seashell, Nuchal Ligament, Ligament
Document Summary
There are 4 anterior pectoral muscles that move the pectoral girdle: pectoralis major, pectoralis minor, subclavius, serratus anterior. Pectoralis major is a fan shaped muscle sea shell . Origin: medial 2/3 clavicle, anterior surface of sternum, upper 6 costal cartilages & aponeurosis of external oblique. Insertion: lateral lip of intertubercular sulcus of the humerus. Action: adduction, medial rotation, + flexion of the humerus: also responsible for keeping arm attached to trunk, upper & lower fibers work in opposition to each other. Insertion: coracoid process of scapula + medial border of scapula. Blood supply: thoracoacromial & lateral thoracic artery. A: stabilizing the scapula used when you stretch upper limb forward to touch something out of your reach. Additional info: pectoralis minor forms bridge with coracoid process under which nerves and vessels pass, we retract the shoulder to work out pecs because stretching & retraction of pec. minor. Action: depresses the clavicle & helps raise 1st rib when clavicle raises.
