Extensor carpi ulnaris muscle

Extensor carpi ulnaris Muscle Anatomy

Extensor carpi ulnaris is a fusiform muscle in the posterior forearm. It spans between the elbow and the base of the little finger. Like all the muscles of this compartment, the extensor carpi ulnaris works as an extensor of the wrist. Moreover, due to its specific course, this muscle also acts to adduct the hand.

Origin

It originates from the lateral epicondylar of the humerus and the posterior border of the ulna.

Insertion

It inserts on the base of the fifth metacarpal bone.

Nerve supply

It is innervated by the posterior interosseous nerve.

Blood supply

It is supplied by the Radial recurrent artery and posterior interosseous artery.

Action

It extends and adducts the hand at the wrist joint.

The oblique course of extensor carpi ulnaris orientates its direction of pull posterolaterally, meaning that its contraction results in a combined extension and adduction (ulnar deviation) of the hand.

Strengthening Exercises

1. Empty Handshakes Exercise

• For this exercise, you‘ll need a flat surface like a table.
• Your forearm should start by resting on the table. You can be seated or standing.
• Your hand and wrist should be hanging off the table.
• Turn your hand to the side as if you were going to shake someone‘s hand. This is the starting position.
• To complete the exercise, move your hand up and down in a chopping motion.
• Hold your movement at the top and at the bottom of the movement.
• Complete the action for 3 sets of 10 reps.

2. Wrist Extension Exercise

• For this exercise, you‘ll need a flat surface like a desk or a tabletop. You‘ll also need a lightweight dumbbell, weighing around 1-2 lbs.
• Standing or sitting with your feet shoulder-width apart, grab the dumbbell with an overhand grip and lay it on the tabletop, with your wrist and working hand hanging off the table. Your palm should be facing down.
• When you‘re ready, pull the dumbbell up by bending the wrist up and extending it as high as possible.

Stretching Exercise

• Extend your right arm in front of you with your palm facing downward.
• Bend the wrist of your right arm, pointing your hand toward the ground.
• Using your left hand, bend your wrist in an even more downward direction.
• You should feel the stretch through the top of your forearm.
• Hold the stretch for 10-15 seconds, repeating as needed.

Clinical Relevance

• The extensor carpi ulnaris is an important muscle in the activity of the wrist and forearm that contributes not only to the extension and adduction of the wrist but also to its medial stability.
• It is most commonly injured in athletes subject to forceful wrist movements.
• Repetitive flexion and extension of the wrist can lead to tenosynovitis due to the irritation of the tendon and the sheath that holds it in place.
• Continued excessive stress on the tendon can cause structural damage which can lead to a partial tear.

Tennis Elbow:

Tennis elbow is a frequent injury of the extensor carpi ulnaris. People who engage in repeated arm, elbow, and wrist motions, particularly while they are firmly grasping an object, are more likely to get this injury. Pain when shaking hands or squeezing/gripping an object are some signs of an extensor carpi ulnaris injury. When a person flexes their wrist firmly, the discomfort gets worse.

This pain worsens because the extensor carpi ulnaris, which glides along the medial epicondyle of the humerus when the arm is extended, has been injured close to the elbow. As a result, the damage that already exists becomes irritated. Tennis elbow can be treated with Rest, physical therapy, occupational therapy, elbow brace, pain relieving anti-inflammatory drugs, and rest.

Extensor carpi ulnaris muscle Injury treatment

Imaging (CT, MRI, ultrasound) is most frequently required for the diagnosis of ECU damage. A doctor will decide on a course of therapy for the ECU damage after diagnosing it. This decision will be based on how severe the injury is.

Conservative therapies involve casting the afflicted wrist to immobilize and stabilize it. In order to be sure that all wrist movement has been halted, a lengthy arm cast could be necessary. The treating doctor will decide how long the patient will be immobile. The cast will be taken off when the immobilization time is over, and more damage investigation will be needed. Invasive treatments may be necessary if the damage did not heal with conservative courses of treatment or if the injury was initially too severe for conservative care.

The cast will be taken off after the immobilization period is completed, and additional injury analysis will be needed. Invasive procedures can be required if the injury did not get better after receiving conservative care or if it was too severe for conservative care to begin with.

The two most common invasive procedures are surgeries and steroid injections. Although surgical repair or rebuilding of the ECU is not frequently necessary, it might be in the case of a serious ECU injury.

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