Question 31: What is the primary use of a knuckle bender splint?
- A. Ulnar nerve palsy (Correct Answer)
- B. Radial nerve palsy
- C. Median nerve palsy
- D. Axillary nerve palsy
Explanation: ***Ulnar nerve palsy***
- A knuckle bender splint is primarily used to counteract the characteristic **claw hand deformity** seen in ulnar nerve palsy [1] by maintaining the **metacarpophalangeal (MCP) joints** in flexion.
- This splint helps improve function by preventing hyperextension of the MCP joints, which commonly occurs due to the unopposed action of the extensor muscles when the ulnar nerve is compromised.
*Radial nerve palsy*
- Radial nerve palsy typically results in **wrist drop** and an inability to extend the wrist and fingers, which is managed with wrist extension splints, not knuckle benders.
- The primary goal of splinting in radial nerve palsy is to support the wrist in extension to facilitate grasping and carrying objects.
*Median nerve palsy*
- Median nerve palsy causes problems with thumb opposition and sensation in the first three and a half digits, often leading to an **ape hand deformity**.
- Splints for median nerve palsy focus on maintaining the thumb in opposition, such as a **thumb spica splint**, which differs from a knuckle bender.
*Axillary nerve palsy*
- Axillary nerve palsy primarily affects the **deltoid muscle**, leading to weakness in shoulder abduction and external rotation.
- Splinting for axillary nerve palsy typically involves shoulder immobilizers or abduction splints, which address shoulder joint positioning rather than hand function.