Question:medium
What is the nerve supply of the marked structure in the given image?
What is the nerve supply of the marked structure in the given image?
Show Hint
First lumbrical belongs to the lateral two - think MEAT-LOAF.
Updated On: Jun 23, 2026
- Anterior interosseous nerve
- Posterior interosseous nerve
- Ulnar nerve
- Median nerve
Show Solution
The Correct Option is D
Solution and Explanation
Step 1: Identify the muscle. The arrow points to the radial-most lumbrical, the first lumbrical, which arises from the flexor digitorum profundus tendon to the index finger.
Step 2: Apply the innervation rule for intrinsic hand muscles. The deep branch of the ulnar nerve handles almost everything in the hand, but a small lateral group is carved out for the median nerve - the thenar eminence and the first two lumbricals.
Step 3: Since the first lumbrical sits in that lateral median-supplied group, its motor fibres travel in the median nerve. The MEAT-LOAF aid confirms $Median \rightarrow$ Lateral two lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis.
Step 4: Eliminating distractors: the ulnar nerve supplies the third and fourth lumbricals only; the interosseous nerves are forearm branches that never reach these intrinsic muscles. Hence the correct supply is the median nerve.
\[\boxed{\text{Median nerve}}\]
Step 2: Apply the innervation rule for intrinsic hand muscles. The deep branch of the ulnar nerve handles almost everything in the hand, but a small lateral group is carved out for the median nerve - the thenar eminence and the first two lumbricals.
Step 3: Since the first lumbrical sits in that lateral median-supplied group, its motor fibres travel in the median nerve. The MEAT-LOAF aid confirms $Median \rightarrow$ Lateral two lumbricals, Opponens pollicis, Abductor pollicis brevis, Flexor pollicis brevis.
Step 4: Eliminating distractors: the ulnar nerve supplies the third and fourth lumbricals only; the interosseous nerves are forearm branches that never reach these intrinsic muscles. Hence the correct supply is the median nerve.
\[\boxed{\text{Median nerve}}\]
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