(65) 8896 3604

Call Us
(65) 6836 6636

(65) 8896 3604

Call Us
(65) 6836 6636

Trigger Finger

What is the ECU tendon?

The ECU tendon is the extensor carpi ulnaris tendon. It is one of the many extensor tendons on the back of the wrist which extends the wrist, thumb or fingers.

The ECU tendon is along the little finger side of the wrist. We doctors call it the “ulnar” side of the wrist. It is a powerful wrist extensor – it moves the wrist backwards.

The ECU tendon is the “yellow” tendon in this picture.

What is the ECU Subsheath?

The extensor tendons on the back of the wrist are held down to the bones by a series of fibrous tunnels or sheaths.

The ECU subsheath holds the ECU onto the groove of the distal ulnar bone.

What is an ECU Subsheath Tear or Injury?

The ECU subsheath can tear and the ECU tendon may pop out of place (sublux or dislocate out of the groove) causing a snapping sensation and/or pain.

This injury can present in weight lifters, tennis players and golfers amongst other sports.

What Are the Symptoms?

  • Pain on the ulnar side of the wrist.
  • Pain on pronation or supination of the wrist.
  • Pain on wrist extension.
  • Popping or snapping of the tendon on the wrist.

What Investigation to Do?

An MRI scan is helpful to assess the ECU tendon as well as to see if it is resting in the right position. This MRI showed that the tendon was subluxed out of the ulnar styloid groove. This indicated a subsheath injury.

The ECU tendon (arrow) is popped out of position due to ECU subsheath tear.

What are the Possible Treatments?

Treatments include:

  1. Rest the wrist joint by casting it in pronation.
  2. Oral anti-inflammatory medications.
  3. Surgery – Subsheath repair.


All Services and Treatments


Dr HC Chang

  • 16 years of experience in surgical and non-surgical procedures in sports injuries as a Sports Orthopaedic Specialist in Singapore.
  • Received multiple awards and accolades in the Orthopaedic field.
  • He is a USA Sports Medicine Fellowship trained Orthopaedic Surgeon and is a member of the Arthroscopy Association of North America as well as the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine.
  • Published many acclaimed articles on Sports Medicine. If you are experiencing one or more of the symptoms mentioned above, it is important to get a prompt and accurate diagnosis to determine the severity of your injury and get proper treatment immediately.


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