A 20-year-old woman with anterior shoulder dislocation has persistent wasting and weakness of the deltoid and loss of sensation over the 'regimental badge' area 6 weeks post reduction. The nerve injured is:

• A Long thoracic nerve — causing serratus anterior weakness and winging of scapula
• B Suprascapular nerve — supraspinatus/infraspinatus weakness
• C Axillary nerve — deltoid paralysis and sensory loss over lateral shoulder ✓
• D Radial nerve — wrist drop and sensory loss dorsal hand

Explanation

Axillary nerve injury is the most common nerve injury associated with anterior shoulder dislocation (5–10% incidence) because the nerve runs through the quadrilateral space immediately below the glenohumeral joint and is stretched by inferior humeral head displacement. It supplies the deltoid (shoulder abduction), teres minor, and the sensory 'regimental badge' area (lateral upper arm via the superior lateral cutaneous nerve of the arm). Wasting of the deltoid + loss of regimental badge sensation = axillary nerve palsy. Most recover spontaneously within 3–4 months; EMG at 3 months guides prognosis. If no recovery by 4–6 months, surgical exploration is considered.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.