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), spine and cranial border of the scapula.
Insertion
Greater tubercle of the humerus (tuberculum majus).
Action
Extends and stabilises the shoulder.
Innervation
Suprascapular nerve (n. suprascapularis).
Clinical relevance
Tendinopathy and mineralisation of the supraspinatus tendon are recognised causes of forelimb lameness in medium and large breeds. Injury to the suprascapular nerve causes atrophy of the supraspinatus and infraspinatus, leaving the spine of the scapula very prominent.