What is the primary function of the 1st dorsal interossei muscle?

The primary function of the 1st dorsal interossei muscle is indeed to facilitate the abduction of the index finger. This muscle is located between the metacarpal bones and plays a crucial role in the movement of the fingers. Specifically, it is responsible for pulling the index finger away from the middle finger, thus aiding in the spreading of the fingers, which is essential for grasping and manipulating objects.

This abduction movement is an important component of hand function, allowing for greater range and dexterity. The first dorsal interossei is one of the muscles that enables this movement, making it integral to various hand activities.