Original Editor - Wendy Walker

Lead Editors - Kate Sampson, Wendy Walker, Kim Jackson, Oyemi Sillo and Naomi O'Reilly  


A thick, triangular muscle; one of the 4 muscles which comprise the Rotator Cuff of the shoulder.

Infraspinatus muscle back2.png


The infraspinatus fossa of scapula, with some fibres arising from the infraspinatous fascia which covers the muscle and separates it from Teres Major and Teres Minor.[1]


The posterior aspect of greater tuberosity of humerus, and the capsule of shoulder joint.[2]

Nerve Supply

Suprascapular Nerve (C5 & C6)[3]

Blood Supply

Suprascapular and circumflex scapular arteries.[3]


Infraspinatus is the main external rotator of the shoulder joint.

It assists in producing shoulder extension.

With the arm fixed, it abducts the inferior angle of the scapula. [2]


It provides the primary muscle force for external rotation of the shoulder.

Along with the rest of the Rotator Cuff muscles it provides stability to the shoulder complex.[3]



  1. Gray H. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918. Available from (accessed on 29/2/2016)
  2. 2.0 2.1 Wheeles CR. Infraspinatus. Available from: (last accessed 29/2/2016)
  3. 3.0 3.1 3.2 AnatomyExpert. 3D Infraspinatus- infraspinatus. Available from: (last accessed on 29/2/2016)