Question:medium
What is the function of the muscle shown in the picture?
What is the function of the muscle shown in the picture?
Show Hint
Lumbricals flex the MCP joints (the writing position).
Updated On: Jun 24, 2026
- Flexion
- Extension
- Adduction
- Abduction
Show Solution
The Correct Option is A
Solution and Explanation
Step 1: Identify the intrinsic hand muscle depicted - the lumbricals, which uniquely bridge a flexor tendon (flexor digitorum profundus) to an extensor apparatus (the dorsal extensor hood).
Step 2: This flexor-to-extensor link lets the lumbricals bend the knuckles (flex the MCP joints) and straighten the fingers (extend the IP joints) at the same time - the classic lumbrical grip used in writing. Of the four choices, flexion is the action being asked, so flexion is correct.
Step 3: Cross off the distractors. Pure extension is not the lumbrical effect at the MCP joints. Finger abduction belongs to the dorsal interossei (DAB) and finger adduction to the palmar interossei (PAD); neither is a lumbrical function.
\[\boxed{\text{Flexion}}\]
Step 2: This flexor-to-extensor link lets the lumbricals bend the knuckles (flex the MCP joints) and straighten the fingers (extend the IP joints) at the same time - the classic lumbrical grip used in writing. Of the four choices, flexion is the action being asked, so flexion is correct.
Step 3: Cross off the distractors. Pure extension is not the lumbrical effect at the MCP joints. Finger abduction belongs to the dorsal interossei (DAB) and finger adduction to the palmar interossei (PAD); neither is a lumbrical function.
\[\boxed{\text{Flexion}}\]
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