The supraspinatus muscle abducts and laterally rotates the shoulder, depresses, and stabilizes the humeral head in the glenoid.  Because this muscle passes under the acromion, it is particularly vulnerable to injury when the shoulder is depressed.  If the humeral head glides superiorly, does not glide inferiorly during shoulder flexion and abduction, or does not rotate laterally enough to prevent impingement of the greater tuberosity against the coracoacromial ligament, then the supraspinatus muscle and tendon are exposed to compression forces.

Actions

• Abduct the shoulder (glenohumeral joint)
• Stabilizes the head of the humerus in the glenoid cavity

Origin

• Supraspinous fossa of the scapula

Insertion

• Greater tubercle of the humerus

Nerve Innervation

• Suprascapular