The dorsal interossei are a group of four muscles located in the hand. They are situated between the metacarpal bones and are responsible for the abduction of the fingers, meaning they help spread the fingers apart. These muscles play a crucial role in hand movements and grip strength. Each dorsal interosseus muscle originates from the adjacent sides of two metacarpal bones and inserts into the extensor expansion of the fingers. They are innervated by the ulnar nerve, which is essential for fine motor control and coordination in the hand.