The pen test for the hand specifically assesses median nerve function by observing the thumb's ability to abduct.
Understanding the Pen Test
This test is used to check for potential median nerve damage, which can lead to specific movement impairments in the hand. Here's how the test is conducted:
Test Procedure
- The patient places their hand flat on a table with the palm facing up.
- The examiner then presents a pen, and the patient is instructed to touch the pen with their thumb by moving it away from the rest of the hand.
- Positive Result: If the patient is unable to abduct their thumb (move it away from the palm), it indicates possible median nerve damage, as described in the reference.
Why this Test Works
The median nerve is crucial for controlling certain muscles in the hand, including those responsible for thumb abduction. Damage to this nerve hinders the ability to perform this specific movement.
Summary Table
| Test Step | Expected Result | Interpretation |
|---|---|---|
| Hand flat, palm up | Patient moves thumb to touch pen | Normal median nerve function |
| Patient attempts thumb abduction | Patient cannot abduct thumb | Potential median nerve damage |
Important Note:
The test is used as an indicator of potential nerve issues, but a comprehensive neurological examination is crucial to make a formal diagnosis and understand the cause of nerve damage.
