An ultrasound-guided axillary brachial plexus block produces dense sensory block in the median, ulnar and radial nerve territories, yet the patient moves his elbow and the surgeon notes active flexion at the elbow against gravity. Which nerve was most likely missed?

• A Suprascapular nerve
• B Radial nerve
• C Medial cutaneous nerve of forearm
• D Musculocutaneous nerve ✓

Explanation

The musculocutaneous nerve leaves the brachial plexus sheath proximally and pierces the coracobrachialis, so at the axillary level it often lies outside the sheath within the substance of coracobrachialis. It is therefore the nerve most frequently spared by an axillary block, producing preserved elbow flexion through the biceps. Radial territory block was present here, and the other two nerves do not supply elbow flexion.

Reference: Morgan and Mikhail Clinical Anesthesiology, 7th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.