Which muscle does not receive innervation from the axillary nerve?

Which muscle does not receive innervation from the axillary nerve?

• A. Deltoid
• B. Teres minor
• C. Infraspinatus
• D. Subscapularis

Answer: (C)

The axillary nerve supplies the deltoid and teres minor, while the infraspinatus is innervated by the suprascapular nerve. Subscapularis gets its nerves from the upper and lower subscapular nerves. So the muscle that does not receive innervation from the axillary nerve is the infraspinatus. Knowing these patterns helps explain clinical signs: weakness in external rotation points to infraspinatus (often due to suprascapular nerve injury), while axillary nerve injury primarily affects the deltoid and teres minor, impairing arm abduction beyond about 15 degrees and external rotation.

The axillary nerve supplies the deltoid and teres minor, while the infraspinatus is innervated by the suprascapular nerve. Subscapularis gets its nerves from the upper and lower subscapular nerves. So the muscle that does not receive innervation from the axillary nerve is the infraspinatus.

Knowing these patterns helps explain clinical signs: weakness in external rotation points to infraspinatus (often due to suprascapular nerve injury), while axillary nerve injury primarily affects the deltoid and teres minor, impairing arm abduction beyond about 15 degrees and external rotation.