Also called: FDP
The flexor digitorum profundus is the deepest flexor of the fingers. It arises from the proximal ulna and interosseous membrane and inserts on the distal phalanges of digits two to five. The anterior interosseous branch of the median nerve supplies the radial half and the ulnar nerve the ulnar half. It flexes the distal interphalangeal joints.
| Origin | Proximal three quarters of the medial and anterior ulna and the interosseous membrane. |
|---|---|
| Insertion | Palmar surfaces of the bases of the distal phalanges of the four fingers. |
| Innervation | Radial half (index and middle fingers): anterior interosseous nerve, a branch of the median nerve. Ulnar half (ring and little fingers): ulnar nerve. Segments C8-T1. |
| Blood supply | Anterior interosseous artery and ulnar artery. |
| Action | Flexes the distal interphalangeal joints and assists flexion of the other finger joints and the wrist. |
3D model: BodyParts3D (CC BY 4.0), adult male reference anatomy. Highlighted structure shown with nearby bones for context.
It is the only muscle that flexes the distal interphalangeal joints, which is why it is tested by asking a patient to bend the tip of each finger while the middle joint is held straight.
The median nerve (anterior interosseous branch) supplies the index and middle finger parts, and the ulnar nerve supplies the ring and little finger parts.
It is a rupture of the flexor digitorum profundus tendon from its insertion on the distal phalanx.
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