The flexor digitorum profundus is a muscle within the deep compartment of the anterior forearm.
- Attachments: Originates from the ulna and associated interosseous membrane. At the wrist, it splits into four tendons. These pass through the carpal tunnel and attach to the base of the distal phalanx of the each digit.
- Actions: Flexion at the distal interphalangeal joint of the digits. It also performs flexion at the wrist, metacarpophalangeal and proximal interphalangeal joints.
- Innervation: The medial half of the muscle (acts on the little and ring fingers) is innervated by the ulnar nerve. The lateral half (acts on the middle and index fingers) is innervated by the anterior interosseous branch of the median nerve.
- Blood supply: Ulnar artery
