The dorsal interossei are intrinsic muscles of the hand located superficially on the dorsum of the hand and can be easily palpated between the metacarpal heads. They originate from the lateral and medial surfaces of the metacarpals and attach into the extensor hood and proximal phalanx of each finger. The main action of the dorsal interossei muscles is the abduction of the digits, and they also assist in flexion at the metacarpophalangeal joints and extension at the interphalangeal joints.
In terms of innervation, the dorsal interossei muscles receive nerve impulses from the ulnar nerve, and they are also supplied by the dorsal metacarpal arteries.
Figure 1 shows the dorsal and palmar interossei of the hand.
The dorsal interossei muscles are important stabilizers of the hand, and they contribute significantly to the movement of the digits. They play a vital role in the performance of activities such as writing, gripping the handle of a tool or turning a key.
The dorsal interossei also help support the arches of the hand and are essential for grip strength, pinch strength, and the overall strength of the hand. They work together with the flexor digitorum profundus, flexor digitorum superficialis, and the other interossei muscles to provide mobility to the fingers, thumb, and wrist.
The dorsal interossei are active during dynamic movements like typing and playing the piano, but they can also be active during static activities such as holding an object. They are also important stabilizers during fast motions such as throwing a ball, which requires rapid changes in finger and thumb position.
Injury, overuse, or weakness of the dorsal interossei can lead to pain and decreased mobility and strength of the hand. Thus, it is important to keep these muscles strong and healthy with regular stretching and strengthening exercises.
The dorsal interossei contribute to a wide range of activities, from everyday tasks to more specialized activities such as sports and musical performance. They play an important role in the movement and stabilization of the hand, and proper care should be taken to ensure their health and strength.
