Extensor Carpi Ulnaris Anatomy
Origin: Humerus (lateral epicondyle via common extensor tendon), Ulna (posterior border by an aponeurosis)
Insertion: 5th metacarpal bone (tubercle on medial side of base)
Innervation: Cervical root(s): C7 and C8
Nerve: Radial nerve (posterior interosseous branch)
Diagrams & Photos
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The extensor carpi ulnaris muscle and tendon. -
The extensor carpi ulnaris muscle and tendon (ECU).
Key Points
- The ECU is the weakest of the wrist extensors.
- The ECU ulnar deviates the wrist during extension.
- The ECU muscle is in a sub fascial extensor compartment.
- The ECU passes through a groove in the distal ulna and through the sixth extensor compartment at the wrist.
- Inside the sixth extensor compartment the ECU is surrounded by a sub-sheath.