Author: Dr Peter de Souza
Last modified: 14 November 2022

The infraspinatus muscle is a thick triangular shaped muscle which arises from the infraspinous fossa below the spine of the scapula. It forms a tendon which inserts on the middle facet of the greater tubercle of the humerus.

Origin

  • Infraspinous fossa on the dorsal surface of scapula (below the spine of the scapula)

Insertion

  • Greater tubercle of humerus (middle facet)

Action

  • Lateral rotation of the humerus
  • Assists in stabilisation of the glenohumeral joint

Innervation

  • Suprascapular nerve: C5, 6

Blood Supply

  • Suprascapular nerve: C4, 5, 6

Antagonist

  • Suprascapular and circumflex scapular arteries