Limited time75% off all plans

FMGE 2010 — Anatomy

Q: Partial claw hand is caused by lesion involving the:

Ulnar nerve. ***Ulnar nerve*** - A lesion of the **ulnar nerve** causes a **partial claw hand** (also called "ulnar claw") because the **medial two lumbricals** (which flex the MCP joints and extend the IP joints of the 4th and 5th digits) and the **interossei** are paralyzed [1]. - This leads to hyperextension at the **metacarpophalangeal (MCP) joints** and flexion at the **interphalangeal (IP) joints** of the **4th and 5th fingers only** (hence "partial") [1]. - The lateral two fingers (index and middle) are spared because their lumbricals are supplied by the median nerve [1]. *Anterior interosseous nerve* - Injury to the **anterior interosseous nerve** primarily affects the **flexor pollicis longus**, **flexor digitorum profundus** (index and middle fingers), and **pronator quadratus**. - This results in the inability to make an "OK" sign (pinch sign) and does not typically cause a claw hand deformity. *Radial nerve* - A **radial nerve** lesion leads to **wrist drop** and the inability to extend the wrist and fingers. - This deformity is distinct from a claw hand, which involves hyperextension at the MCP joints and flexion at the IP joints. *Median nerve* - A **median nerve** lesion results in a "hand of benediction" or "ape hand" deformity, affecting the **thenar muscles** and the **lateral two lumbricals** [1]. - This involves paralysis of the thumb's opposition and the inability to flex the index and middle fingers, not the characteristic clawing of the 4th and 5th digits. [Practice more Anatomy PYQs on OnCourse]

1 Previous Year Questions with Answers & Explanations

Questions

All Subjects Anatomy (1)Biochemistry (2)Forensic Medicine (7)Internal Medicine (1)Pediatrics (2)Pharmacology (1)Surgery (3)

Partial claw hand is caused by lesion involving the: