Overview
A thick muscle that fills the supraspinous fossa and bulges beyond the cranial border of the scapula. Together with the infraspinatus it acts as a contractile ligament stabilising the shoulder joint.
Origin
Supraspinous fossa (fossa supraspinata) and spine of the scapula.
Insertion
Greater tubercle of the humerus (tuberculum majus).
Action
Extends and stabilises the shoulder.
Innervation
Suprascapular nerve (n. suprascapularis).
Clinical relevance
Suprascapular nerve injury, for example in brachial plexus injuries after a road accident, causes atrophy of the supraspinatus and infraspinatus and leaves the spine of the scapula very prominent.