Nerve · Shoulders

Suprascapular nerve

Nervus suprascapularis

The suprascapular nerve supplies supraspinatus and infraspinatus — two of the four rotator cuff muscles — and carries sensation from the shoulder joint itself, but from no skin anywhere. That combination explains its clinical signature: a deep, poorly localised ache in the back of the shoulder that the patient cannot point to, with weakness of starting abduction and of turning the arm outward, and never any numbness. It is squeezed at two named notches on the scapula, and which notch matters: at the suprascapular notch both muscles are affected, while at the spinoglenoid notch further along, only infraspinatus is — so external rotation weakens while abduction is spared. Repeated overhead activity is the usual context.