Median nerve sensory and motor distribution — FRCA Primary MCQ

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ModerateAnatomyMedian nerve sensory and motor distributionFRCA Primary

A patient has numbness of the palmar aspect of the lateral three and a half fingers after an upper limb regional technique. Thumb opposition is weak. Which nerve is most likely affected?

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Correct answer: B — Ulnar nerve

The median nerve supplies palmar sensation to the lateral three and a half fingers and motor fibres to thenar muscles involved in thumb opposition. Ulnar nerve injury affects the medial one and a half fingers and many intrinsic hand muscles. Radial nerve injury produces dorsal sensory symptoms and wrist extension weakness. The pearl is to link sensory territory with motor deficit for peripheral nerve localisation.

Reference: RCoA Primary FRCA Syllabus 2026; Anatomy for Anaesthetists