Upper limb
Supraspinatus
Musculus supraspinatus
- Origin
- Supraspinous fossa of the scapula
- Insertion
- Greater tubercle of the humerus
- Function
- Initiates shoulder abduction (first ~15°) and stabilizes the glenohumeral joint (rotator cuff)
- Innervation
- Suprascapular nerve (C4–C6)
- Movement & chain
- Initiates abduction (first ~15°) and then centers the humeral head in the glenoid cavity throughout abduction. Without this centering, the head rides up against the acromion.
- Palpation
- Not directly palpable: the muscle belly lies in the supraspinous fossa beneath trapezius. The tendon can be approached indirectly just anterior to the front edge of the acromion, with the arm extended and internally rotated.
- Clinical
- The most commonly affected rotator cuff tendon. Impingement and degenerative tears are common; a painful arc between 60° and 120° of abduction is the classic finding.
- Segmental innervation
- Suprascapular nerve, C4–C6, with the main contribution from C5.
- In clinical practice
- Subacromial bursa injections and clinical impingement tests (e.g. the empty-can test) target the area just below the acromion, where this muscle's tendon is most vulnerable.
- Region in the model
- Upper limb