Upper limb
Extensor Carpi Radialis Brevis
Musculus extensor carpi radialis brevis
- Origin
- Lateral epicondyle of the humerus (common extensor tendon)
- Insertion
- Base of the third metacarpal bone
- Function
- Extends the wrist and stabilizes it during finger movements
- Innervation
- Radial nerve (deep branch/posterior interosseous nerve), C7–C8
- Movement & chain
- Works together with extensor carpi radialis longus and ulnaris to stabilize the wrist in extension, providing a fixed base for powerful finger flexion (for example when making a fist).
- Palpation
- Slightly deeper and more distal than extensor carpi radialis longus; harder to distinguish separately on the proximal forearm.
- Clinical
- This muscle is the most common source of complaints in lateral epicondylitis (tennis elbow), due to repeated eccentric loading from the lateral epicondyle.
- Segmental innervation
- Part of the C7–C8 myotome via the deep branch of the radial nerve.
- In clinical practice
- Focus on hand function and edema prevention; ensure IV cannulas and splints maintain functional hand position to prevent joint contractures.
- Region in the model
- Upper limb