Muscle
Extensor digitorum
Main finger extensor
High-yield
Extends the MCP joints of the four fingers via extensor expansions; posterior interosseous nerve (deep radial).
Overview
The principal extensor of the fingers, its four tendons crossing the dorsum of the hand and forming the extensor expansions.
Reference facts
- Origin
- Lateral epicondyle of the humerus (common extensor origin)
- Insertion
- Extensor expansions of the medial four fingers (middle and distal phalanges)
- Action
- Extends the fingers at the MCP joints and assists wrist extension
- Innervation
- Posterior interosseous nerve (deep branch of radial, C7, C8)
- Blood supply
- Posterior interosseous artery
Frequently asked questions
What does the extensor digitorum do?
The extensor digitorum extends the fingers at the MCP joints and assists wrist extension.
What nerve innervates the extensor digitorum?
The extensor digitorum is innervated by the posterior interosseous nerve (deep branch of radial, C7, C8).
Where does the extensor digitorum attach?
The extensor digitorum originates from the lateral epicondyle of the humerus (common extensor origin) and inserts on the extensor expansions of the medial four fingers (middle and distal phalanges).
What is the blood supply of the extensor digitorum?
The extensor digitorum is supplied by the posterior interosseous artery.