What nerve damage causes numbness in the虎口 (web of the thumb)?
Oct 12, 2022
Source: Cainiu Health
Dr. Yang Jun
Introduction
In general, numbness in the webbing between the thumb and index finger may be caused by damage to the radial nerve, median nerve, or ulnar nerve. If symptoms persist or are severe, prompt medical attention is recommended. The radial nerve is a major nerve in the arm responsible for movement and sensation in parts of the wrist and fingers. Radial nerve injury can lead to abnormal sensation or motor function in the hand area, including numbness in the webbing between the thumb and index finger.
Generally, numbness in the webbing between the thumb and index finger may be caused by damage to the radial nerve, median nerve, or ulnar nerve. If symptoms persist or are severe, it is recommended to seek immediate medical attention. Specific explanations are as follows:
1. Radial Nerve
The radial nerve is a major nerve in the arm responsible for movement and sensation in part of the wrist and fingers. Damage to the radial nerve may cause abnormal sensation or motor function in the hand, including numbness in the webbed area between the thumb and index finger.
2. Median Nerve
The median nerve is one of the primary sensory nerves in the hand, responsible for sensation in the fingers. When the median nerve in the webbing area of the thumb is damaged or compressed, it may lead to numbness. Such injury can result from prolonged poor wrist posture, such as pressure or repetitive motions, leading to nerve compression or damage.
3. Ulnar Nerve
The ulnar nerve is another important nerve in the arm that controls movement and sensation in part of the wrist and hand. It runs along one side of the hand, and if it becomes injured or compressed in the webbing area between the thumb and index finger, it may also cause numbness. Similar to the median nerve, ulnar nerve damage may result from prolonged poor wrist posture or trauma.
In daily life, avoiding maintaining specific hand postures for extended periods—such as prolonged computer use, work-related activities, or sports—can help prevent these conditions.
