What muscles are affected by an injury to the median nerve?

Injury to the median nerve primarily impacts the flexor muscles of the forearm and the thenar muscles. The median nerve innervates the majority of the flexor muscles located in the anterior compartment of the forearm, which are responsible for flexing the wrist and fingers. This includes muscles like the flexor carpi radialis, palmaris longus, and flexor digitorum superficialis.

Additionally, the median nerve also innervates the thenar muscles, which are critical for thumb opposition, abduction, and flexion. These functions are essential for proper prehension and grip, highlighting the significance of the median nerve's role in hand function.

Due to the specific innervation patterns, injuries to the median nerve can lead to characteristic symptoms such as weakness in thumb movement and coordination, as well as potential issues with finger flexion. This combination of affected muscles directly drives the conclusion that an injury to the median nerve predominantly impacts the flexor muscles of the forearm and the thenar muscles.