Infraspinatus (left) (Musculus infraspinatus)
Educational content only — not medical advice.
Anatomy
Fills the infraspinous fossa on the back of the scapula below its spine; the strongest lateral rotator of the arm and a core rotator-cuff member, its fibres running horizontally to the greater tubercle of the humerus.
Origin & insertion
The infraspinous fossa and the fascia covering the muscle. Middle facet of the greater tubercle of the humerus.
Action
Rotates the arm laterally and, with supraspinatus, is the main depressor of the humeral head, protecting the shoulder in every overhead movement.
Innervation
Suprascapular nerve (C5–C6).
Clinical notes
Tendinopathy is typical in throwing and volleyball athletes from repeated external rotation; it is tested by resisted external rotation with the elbow at the side.
Related structures
Educational references
FAQ
What is the role of the Infraspinatus (left)?
Fills the infraspinous fossa on the back of the scapula below its spine; the strongest lateral rotator of the arm and a core rotator-cuff member, its fibres running horizontally to the greater tubercle of the humerus.
Why is the Infraspinatus (left) clinically important?
Tendinopathy is typical in throwing and volleyball athletes from repeated external rotation; it is tested by resisted external rotation with the elbow at the side.
Source & license
BodyParts3D, © The Database Center for Life Science licensed under CC Attribution 4.0 International (https://creativecommons.org/licenses/by/4.0/). license details