Anatomy
Origin:
Upper two-thirds of posterior surface of lateral border of scapula.
Insertion:
Inferior facet of greater tubercle of humerus.
Key Relations:
-The tendon of the muscle passes across and is united with the posterior capsule of the shoulder joint.
-One of the four muscles of the rotator cuff muscle group.
Functions
-Lateral rotation of the arm at the glenohumeral joint (with Infraspinatus).
-Adduction of the arm.
-Contributes to the stability of the shoulder joint with the other rotator cuff muscles.
Supply
Nerve Supply:
Axillary nerve (C5, C6).
Blood Supply:
-Circumflex scapular artery
-Posterior circumflex humeral artery.
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