External occipital protuberance of the skull; Spinous process of C7
Lateral third of the clavicle; Acromion process of the scapula
Concentric Action: Cervical extension, lateral flexion, rotation, scapular elevation
Eccentric Action: Cervical flexion, lateral flexion, rotation, scapular depression
Isometric Action: Stabilizes the cervical spine and scapula, stabilizes the medial border of the scapula creating a stable base for the prime movers during scapular abduction and upward rotation
Cranial nerve XI, ventral rami C2–C4
