A 35-year-old motorcyclist sustains a fracture of the surgical neck of the humerus. On examination, the deltoid muscle is paralysed and there is a small patch of numbness over the regimental badge area of the upper arm. Which nerve is most likely injured?
- A Radial nerve
- B Musculocutaneous nerve
- C Axillary nerve ✓
- D Suprascapular nerve
Correct answer: C. Axillary nerve
Explanation
The axillary nerve winds around the surgical neck of the humerus and is the nerve most commonly injured with this fracture. It supplies the deltoid (abduction 15–90°) and teres minor, and its sensory branch (upper lateral cutaneous nerve of arm) supplies the regimental badge area over the deltoid. Suprascapular nerve palsy would not cause deltoid weakness.
Reference: Maheshwari Essential Orthopaedics, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.