Upper limb
Subscapularis
Musculus subscapularis
- Origin
- Subscapular fossa (anterior surface of the scapula)
- Insertion
- Lesser tubercle of the humerus
- Function
- Internal rotation of the shoulder; as part of the rotator cuff it stabilizes the humeral head in the glenoid fossa
- Innervation
- Upper and lower subscapular nerves (C5-C6)
- Movement & chain
- Works together with the other rotator cuff muscles (supraspinatus, infraspinatus, teres minor) to keep the humeral head centered in the glenoid during arm movements.
- Palpation
- Difficult to palpate directly due to its position against the chest wall; tested indirectly with the "lift-off test" (lifting the hand off the lower back).
- Clinical
- Tears of the subscapularis tendon are less common than of the supraspinatus tendon but cause loss of internal rotation function and shoulder instability.
- Segmental innervation
- C5-C6.
- In clinical practice
- Safe transfer techniques avoiding arm traction (prevents shoulder subluxation in stroke patients); monitor injection sites and offload scapular pressure.
- Region in the model
- Upper limb