Extensor carpi ulnaris

Extensor carpi ulnaris (ECU) is a muscle of the superficial layer of the posterior compartment of the forearm. It is separated from the extensor digitorum and the extensor digiti minimi muscles by a distinct intermuscular septum. It is the only forearm extensor that lies in its own fibro-osseous tunnel at the level of the wrist with its own subsheath as it passes through the 6th extensor compartment of the wrist. At the level of the ulna, it is covered by a subsheath, extensor retinaculum and the linea jugata. It is one of the extrinsic muscles of the hand.

Summary

Related pathology

  • tendinosis and/or tenosynovitis
    • ECU is the second most common site of upper limb tenosynovitis 3
  • subluxation of the ECU tendon with subsheath injury 3
Anatomy: Upper limb
Share article

Article information

rID: 39872
Section: Anatomy
Synonyms or Alternate Spellings:
  • Extensor carpi ulnaris muscle
  • Extensor carpi ulnaris (ECU)
  • Extensor carpi ulnaris tendon

Support Radiopaedia and see fewer ads

Cases and figures

  • Figure 1: extensor compartments of the wrist
    Drag here to reorder.
  • Axial images at l...
    Case 1: ECU tendinopathy
    Drag here to reorder.
  • Figure 2: ECU subluxation (red arrow)
    Drag here to reorder.
  • Case 2: ECU tendinosis and tenosynovitis
    Drag here to reorder.
  • Case 3: subluxation - traumatic
    Drag here to reorder.
  • Updating… Please wait.

     Unable to process the form. Check for errors and try again.

     Thank you for updating your details.