Infraspinatus

Original Editor - Wendy Walker

Lead Editors - Kate Sampson, Wendy Walker, Oyemi Sillo, Naomi O'Reilly and George Prudden  

Description

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

Infraspinatus muscle back2.png

Origin

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]

Insertion

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]

Action

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]

Function

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]

Resources

Recent Related Research (from Pubmed)

References

  1. Gray H. Anatomy of the Human Body. Philadelphia: Lea & Febiger, 1918. Available from https://www.bartleby.com/107/123.html (accessed on 29/2/2016)
  2. 2.0 2.1 Wheeles CR. Infraspinatus. Available from: http://www.wheelessonline.com/ortho/infraspinatus (last accessed 29/2/2016)
  3. 3.0 3.1 3.2 AnatomyExpert. 3D Infraspinatus- infraspinatus. Available from: http://www.anatomyexpert.com/app/structure/5510/554/ (last accessed on 29/2/2016)