M. supraspinatus

The supraspinatus is a rotator cuff muscle that extends from the supraspinous fossa to the greater tubercle of the humerus and contributes to elevation of the arm and dynamic stabilisation of the glenohumeral joint.

• Contributes to abduction/elevation of the humerus.
• Contributes to dynamic stabilisation of the glenohumeral joint.
• Together with the other rotator cuff muscles, contributes to compression and centring of the humeral head relative to the glenoid.

Origin

Supraspinous fossa of the scapula.

Insertion

Superior facet of the greater tubercle of the humerus.

Course

The muscle fibres run laterally from the supraspinous fossa towards the humerus. The tendon passes beneath the acromion and distally forms part of the continuous tendon complex of the rotator cuff.

Innervation

Suprascapular nerve, predominantly from C5–C6.

The supraspinatus contributes to elevation of the arm and to the dynamic stability of the glenohumeral joint. As part of the rotator cuff, the muscle generates compressive force that helps stabilise the humeral head against the glenoid. Its overall contribution to movement and stability arises in cooperation with, among others, the other rotator cuff muscles and the deltoid, and varies with joint position and loading. The supraspinatus should therefore not be considered a muscle with a single isolated function.

The supraspinatus and its tendon may be involved in rotator cuff-related complaints and structural abnormalities. Findings such as pain during arm elevation, reduced strength, or symptom provocation during resisted testing may prompt further assessment of the rotator cuff, but are insufficient on their own to attribute symptoms specifically to the supraspinatus. Findings should therefore be interpreted in conjunction with the history, function, and the remainder of the clinical examination.

The muscle belly is located in the supraspinous fossa, superior to the spine of the scapula. Laterally, the musculotendinous structure courses towards the greater tubercle and lies largely deep to the surrounding structures. Palpation may be used for anatomical orientation, but local tenderness cannot reliably demonstrate that the supraspinatus is the cause of shoulder symptoms.

• Origin: supraspinous fossa; insertion: greater tubercle.
• Innervation is via the suprascapular nerve, predominantly from C5–C6.
• The supraspinatus contributes to both elevation and dynamic glenohumeral stability.
• The muscle functions as part of the rotator cuff rather than as an isolated abductor.
• A positive resisted test or local pain does not demonstrate isolated supraspinatus pathology.