Extensor Carpi Ulnaris (ECU) tendonitis

What is the ECU- extensor carpi ulnaris?


Extensor = means it extends or flexes (in the case of ECU, the wrist (carpi), on the ulnar side (ulnaris))

ECU - Extensor Carpi Ulnaris nestles in a cozy groove on the ulna, protected by a subsheath tunnel on the pinky side of the wrist. The tendon runs over and across the ulna, and attaches on the thumb side of the humerus at the elbow. 

The muscle of the ECU enables you to extend and flex the wrist, and is what allows you to move your hand sideways towards the pinky (ulnar deviation) You can see the muscle move when you make a fist and move your fist towards the pinky.  It's responsible for the dreaded tennis elbow.  

The ECU tendon helps maintain the wrist's mobility and stability.  It can be injured when there is forceful rotation, flexing, and deviation - like in golf, tennis, polo, baseball, and weight lifting. Such injuries can cause the subsheath to tear and the ECU to move out of its groove - causing a popping sensation as it rolls on the ulna. 

To understand the ECU better - please watch this short video. It really helps to illustrate what how the ECU works and what it does.


We have been collecting data on patients with Triangular Fibrocartilage Complex (TFCC) tears and ECU injuries since 2004.  We have found that patients who have a TFCC tear often develop symptoms in their ECU.  When the TFCC is treated, the ECU symptoms resolve.   There are also many cases that have been diagnosed as a TFCC injury which are only an ECU issue.  How do I know the difference? 

The test results you get from performing the Weight Bearing Test indicate whether your injury is injured.  If your weight bearing tolerance is normal, then the TFCC is fine and you want to look at the ECU. 

It can be tricky because often a subluxating ECU is the result of an underlying TFCC tear.  


  • Pain on Weight Bearing
  • Injured wrist tests lower than healthy wrist on the Weight Bearing Test
  • Injured wrist tests higher with WristWidget/Taping than without 
  • The WristWidget® will be helpful in recovery


  • No pain on weight-bearing
  • Healthy and injured wrist test the same on the Weight Bearing Test
  • Wrist aches after wearing the WristWidget®
  • Clicking or popping and pain at ECU insertion
  • The WristWidget® will NOT be helpful in recovery


You know you have a TFCC tear when there is a loss of weight-bearing tolerance and an immediate increase with tape or the WristWidget.  You know that the ECU is involved if you have pain to touch at the insertion of the ECU at the back of the hand when the wrist deviates towards the ulna (ulnar deviation). 



The purpose of this article is to address the patients that have a TFCC injury AND an ECU subluxation. However, the following treatment is good for anyone with an ECU issue. There are additional treatments for ECU-only insertion and origin injuries not covered here. If you have an ECU-only injury, please consult your hand therapist for guidance.

  • Wrist extension splinting at night.
  • No stretching for 4 weeks
  • Deep tissue massage
  • Heat to the ECU muscle belly daily.
  • Ice to ECU insertion
  • Acupuncture.
  • After 4 weeks, slowly to stretch.
  • No strengthening until you have at least 65# of weight-bearing ability.  No pain to touch, No pain with stretching.
  • Consider a “Band-it” Tennis Elbow brace to wear during the day. (found online, at pharmacies, and large stores)
  • Use an ergonomic mouse to prevent ulnar deviation, and promote a relaxed, neutral hand position. 
  • Use an ergonomic keyboard to maintain neutral wrist alignment

Please read this Therapist written blog post "How I Healed my Subluxating Extensor Carpi Ulnaris Tendon".

What to do if you have a TFCC injury AND ECU subluxation? 

When the TFCC is injured, the ECU has a lot more strain to it.  Oftentimes, the entire muscle system gets tight and irritated - from wrist to elbow.   

The most important thing to understand is your weight-bearing tolerance.  IF your weight-bearing tolerance is below 45 lbs, you will be spinning your wheels on the treatment of the ECU.  In this case, you need to protect the wrist with a wrist splint at night to prevent stretching of the ECU and further irritation. 

You can calm things down with ice, cortisone injection (it usually does not help with TFCC but can be very helpful to the ECU), deep tissue massage, acupuncture, herbal and diet changes, cupping, dry needling, kinesiotaping, and stretching.  

All of these can help and can be done anytime during your recovery.  I recommend doing one daily until your symptoms resolve.  

ICE for the ECU

Ice is a vasoconstrictor and helpful in decreasing swelling.  Often there is no visible swelling with ECU and TFCC tears.  You can ice the insertion at the wrist and the origin at the elbow.  All you need is a piece of ice and 2 minutes of direct massage to these areas.  You can do this all day long.  

Avoid putting an ice pack on your arm.  This often causes the muscle to tighten- contradicting your objective. 

HEAT for the ECU

Heat is a vasodilator.  It increases the blood flow to the area you are treating.  A heating pad at night around the elbow and forearm can be really helpful.

If you are taking a shower, it is good to run cold water on the arm for a minute followed by heat for 4 minutes.  Repeat 3 times.  Contrast baths are also helpful. 


Chinese medicine has been around a lot longer than western medicine and has validity.  The Chinese MD's describe the ECU along the Small Intestine Meridian. 

Having an acupuncturist evaluate your symptoms is important.  They can treat and recommend herbal remedies.  Many people find this helpful. 

As mentioned, ECU Tendonitis is along the Small Intestine Median - which is related to having GI issues.  Are you having any gall bladder, reflux, ulcer, intestinal problems? If so, they could be related to the ECU injury and you will want to have them addressed. 

Wendy had Instagram LIVE sessions with acupuncturists.  You can find topics discussed and video link here:  https://www.wristwidget.com/blogs/blog-archive/wristwidget-live-topics-of-conversation




KINESIOTAPING for ECU subluxation 

This has gained a lot of attention because it is helpful.  It is a bit tricky to get right.  I would recommend finding a rehabilitation specialist who has been trained in a variety of techniques (Certified Hand Therapist, Occupational or Physical Therapist). Make sure you choose a good quality kinesiotape to avoid any skin irritations.  Please watch the Instagram LIVE video below, as Wendy and Alison Taylor demonstrate the proper technique.  


Stretching is a very important facet of wrist injury recovery. It's important to gently stretch the ECU without causing TFCC pain. Stretch slowly and gently daily. Notice any areas that are painful and as they improve.  

ECU stretch - wrist flexion in a pronated position helps! Do not stretch in supination. Do not stretch without the WristWidget® or until weight bearing is 60 lbs/27kg.




Deep tissue massage is very helpful as it helps to stretch and loosen tight muscles in the arm, shoulders, neck, and back. All of these areas are impacted with TFCC injuries. 


NERVE GLIDING - Posterior Interossei Nerve (PIN)

The posterior interosseous nerve (or dorsal interosseous nerve) is a nerve in the forearm. It is the continuation of the deep branch of the radial nerve after this has crossed the supinator muscle. The supinator and pronator muscles are often imbalanced in TFCC tears.  The pronator gets tight, the supinator gets weak. The Brachioradialis muscle also gets weak in this injury.

I am not sure if the weak or tight muscle contributes to the injury or if the injury contributes to the tight and weak muscles.  Either way, both of these muscles should be examined closely.

You can compare strength and stretch to the other arm and determine if they are involved. If the radial nerve is pinched at the neck or on its path to the hand, it will not conduct electricity to the distal muscles well. 

The PIN is a branch of the radial nerve which starts at the neck. Neck stretching (C5-T1 cervical spine) is important. Take a look at the path of the radial nerve and determine if it is tight anywhere along its path. 

Here are simple and very effective Radial Nerve stretches. 

In summary, supporting the ECU is extremely important when you have a TFCC injury.  There are many treatments available to help. 

As always, send us a note, or fill out our injury submission form at https://bit.ly/ww-injury if you need help on your healing journey. 


Wendy had an Instagram LIVE session devoted to the ECU and shared a ton of information.  The session included a segment with Allison Taylor, the KT Tape expert, to demonstrate how to tape ECU injuries. 

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