Interossei muscles

Muscles located in the hands and feet that play a crucial role in fine motor skills and balance.

Interossei muscles are a group of muscles situated between the bones (metacarpals in the hands and metatarsals in the feet). There are two types: the dorsal interossei, which primarily abduct the digits (move them away from the midline), and the palmar interossei, which primarily adduct the digits (move them toward the midline). These muscles aid in the intricate movements of the fingers and toes, enabling tasks such as gripping and walking with precision.

Terminologia Anatomica

musculi interossei

System

Muscular system

Function

The interossei muscles are instrumental in the fine control and dexterity of the hands and feet. In the hand, the dorsal interossei allow for the spreading apart of the fingers, facilitating actions like grasping larger objects or spreading fingers for typing or playing musical instruments. The palmar interossei enable the fingers to come together, enhancing the ability to hold smaller objects securely. In the foot, these muscles help maintain balance and stability while walking or running, allowing for adaptive movements across different surfaces. The coordination of these muscles not only supports functional tasks but also contributes to proprioception—the body’s ability to sense its positioning and movement in space.

Location

Located between the metacarpal bones of the hand and the metatarsal bones of the foot, the interossei muscles are divided into two groups based on their position. In the hand, the dorsal interossei are found on the dorsal side, situated on the side of each metacarpal that faces away from the midline of the hand. There are four dorsal interossei in each hand, one for each of the second, third, and fourth fingers, as well as one that operates on the thumb side of the second finger. The palmar interossei are located on the palmar side, with three muscles corresponding to the index, ring, and little fingers. In the foot, four dorsal interossei muscles are positioned between the metatarsals, while three palmar interossei are located on the plantar surface of the foot, corresponding to the third, fourth, and fifth toes. This anatomical positioning allows for their efficient function in fine motor control.

Did You Know?

The interossei muscles are essential for activities requiring precision, such as playing musical instruments or typing.
The intrinsic muscles of the hand, including the interossei, play a key role in grip strength and delicacy.
In the foot, interossei muscles assist in maintaining the arch and help adapt the foot's position while walking.