The median nerve in the hand provides both motor and sensory functions crucial for hand movement and sensation.
The median nerve plays a vital role in hand function by controlling specific muscles and relaying sensory information. Here's a more detailed breakdown:
Motor Function
The median nerve controls the following movements in the hand:
- Thumb movement: It innervates the thenar muscles, which are responsible for thumb abduction (moving the thumb away from the hand), opposition (bringing the thumb across the palm to touch the fingertips), and flexion (bending the thumb). These movements are essential for gripping and pinching.
Sensory Function
The median nerve provides sensation to the following areas of the hand:
- Palmar side: It provides sensation to the palmar (palm) side of the thumb, index finger, middle finger, and the radial (thumb) side of the ring finger.
- Dorsal side: It provides sensation to the dorsal (back) tips of the thumb, index finger, middle finger, and radial side of the ring finger.
Clinical Significance: Carpal Tunnel Syndrome
A common condition affecting the median nerve is Carpal Tunnel Syndrome (CTS). This occurs when the median nerve is compressed within the carpal tunnel in the wrist. This compression can lead to:
- Numbness and tingling: Primarily in the thumb, index, middle, and radial half of the ring finger.
- Pain: Often worse at night.
- Weakness: Particularly in thumb movements, making it difficult to grip or perform fine motor tasks.
Summary
In summary, the median nerve enables fine motor control of the thumb and provides sensory feedback from a large portion of the hand, allowing for precise manipulation and interaction with the environment. When compressed, as in carpal tunnel syndrome, significant functional impairment can occur.
