infraépineux

The infra-spinatus muscle is located in the infraspinous fossa of the scapula. It is one of the four muscles of the rotator cuff, along with the supraspinatus, teres minor, and subscapularis. The infra-spinatus originates from the infraspinous fossa and inserts onto the greater tubercle of the humerus. Its primary actions are external rotation and abduction of the arm at the glenohumeral joint. It also plays a role in stabilizing the shoulder joint.

The infra-spinatus is innervated by the suprascapular nerve, which arises from the brachial plexus. This nerve also supplies the supraspinatus muscle. The blood supply to the infra-spinatus comes from the suprascapular artery and the circumflex scapular artery.

Injuries to the infra-spinatus are common, particularly in athletes involved in overhead activities such as throwing or swimming. These injuries can include strains, tears, and tendinitis. Pain in the posterior shoulder, weakness with external rotation, and difficulty with overhead movements are common symptoms. Diagnosis typically involves a physical examination and may be confirmed with imaging studies like MRI. Treatment options range from conservative measures such as rest, ice, and physical therapy to surgical intervention for severe tears.