Which muscle is NOT found in the first dorsal wrist extensor compartment?

The first dorsal wrist extensor compartment is a specific anatomical space in the wrist that contains certain muscles responsible for the extension and abduction of the wrist and thumb. The muscles typically found in this compartment are the abductor pollicis longus and the extensor pollicis brevis. These muscles are crucial for thumb movements, including abduction and extension.

The extensor carpi radialis longus, however, is primarily associated with the second dorsal compartment of the wrist. This muscle plays a significant role in wrist extension and radial deviation but is not contained within the first compartment. Understanding these anatomical relationships helps clarify the specific roles and locations of these muscles during wrist and hand movements.

Overall, the presence of the abductor pollicis longus and extensor pollicis brevis in the first dorsal compartment contrasts with the function and location of the extensor carpi radialis longus, validating the selection of this muscle as the one not found in the first dorsal wrist extensor compartment.