Summary
Origins
- Medial epicondyle of the 🦴 humerus through the common flexor tendon
- Coronoid process of the 🦴 ulna
- Oblique line and superior half of the anterior border of the 🦴 radius
Insertions
- Sides of the middle phalanges of digits two through five via split tendons
Actions
- Flexes proximal interphalangeal joints of digits two through five
- Assists metacarpophalangeal and wrist flexion when gripping
The flexor digitorum superficialis forms the intermediate layer of the anterior forearm. A humero-ulnar head springs from the medial epicondyle, ulnar collateral ligament, and coronoid process, while a radial head arises from the oblique line of the radius. The belly quickly divides into four tendons that travel through the carpal tunnel toward digits two through five.
Each tendon splits around the corresponding flexor digitorum profundus slip and reunites to attach to the sides of the middle phalanx. This pulley arrangement flexes the proximal interphalangeal joints without closing the fist completely, letting artists articulate individual fingers in a relaxed grip.
It works with flexor carpi radialis and palmaris longus to brace the wrist while gripping, and it assists flexor digitorum profundus during forceful finger flexion. extensor digitorum opposes its pull, and pronator teres crosses superficially at the elbow.
Related Muscles
- flexor digitorum profundus
- palmaris longus
- flexor carpi radialis
- flexor carpi ulnaris
- extensor digitorum