Also called: infraspinatus muscle
The infraspinatus is a rotator cuff muscle below the spine of the scapula. It arises from the infraspinous fossa and inserts on the middle facet of the greater tubercle of the humerus. The suprascapular nerve supplies it, and it laterally rotates the arm while stabilising the shoulder joint.
| Origin | Infraspinous fossa of the scapula. |
|---|---|
| Insertion | Middle facet of the greater tubercle of the humerus. |
| Innervation | Suprascapular nerve (C5-C6). |
| Blood supply | Suprascapular artery and circumflex scapular artery. |
| Action | Laterally rotates the arm at the shoulder and stabilises the humeral head. |
3D model: BodyParts3D (CC BY 4.0), adult male reference anatomy. Highlighted structure shown with nearby bones for context.
The infraspinatus is the main lateral rotator of the shoulder, with teres minor. It is covered by a strong fascia and by the posterior deltoid and trapezius.
Its tendon blends with the posterior part of the shoulder joint capsule.
Lateral rotation of the arm and stabilisation of the humeral head.
The suprascapular nerve.
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