Flexor digitorum profundus

A muscle critical for finger flexion and grip strength.

The flexor digitorum profundus is a muscle located in the forearm that plays a key role in bending the fingers. It is a deep muscle, situated beneath the flexor digitorum superficialis, and originates from the anterior surface of the ulna and the interosseous membrane. The muscle inserts into the distal phalanges of the fingers, allowing it to act on the fingertips.

Terminologia Anatomica

flexor-digitorum-profundus

System

Musculoskeletal system

Function

The primary function of the flexor digitorum profundus is to facilitate the flexion of the distal interphalangeal joints of the fingers. This unique capability is essential for grasping and manipulating objects, allowing the hand to perform intricate tasks such as typing or playing musical instruments. It is particularly important for actions that require strong and precise grip, as it allows for full closure of the fingers around various objects. Additionally, this muscle contributes to flexing the proximal interphalangeal joints and is involved in the overall dexterity and functionality of the hand.

Location

The flexor digitorum profundus is located in the deep compartment of the anterior forearm. It begins at the ulna, which is one of the two long bones in the forearm, specifically around the middle third of the bone. As it travels distally, it passes beneath the flexor retinaculum before dividing into four tendons that extend to the fingers. These tendons then pass through the carpal tunnel and attach to the bases of the distal phalanges of the fingers, allowing the muscle to exert its influence on finger movements.

Did You Know?

The flexor digitorum profundus is innervated by the median nerve for the second and third fingers, while the ulnar nerve controls the fourth and fifth fingers.
It is the only muscle capable of flexing the distal interphalangeal joint completely without flexing the proximal interphalangeal joint.
Damage to this muscle or its nerve supply can lead to a condition known as 'claw hand', where the fingers can't fully extend.