By Sarah Barrows
I. Description of Motion
Wrist extension can be described as raising the back of the hand towards the back of the forearm.
The primary muscles involved in wrist extension, which act on the wrist only, are the extensor carpi radialis longus, extensor carpi radialis brevis and the extensor carpi ulnaris.1 All of these muscles need to be fired simultaneously to avoid any radial or ulnar deviation with extension. Secondary wrist extensors, which act on the wrist and hand, include the extensor digitorum, extensor indicis, extensor digiti minimi, and extensor pollicis longus.1 All of the wrist extensor muscles share a common origin – the common extensor tendon from the lateral epicondyle of the humerus.1
The wrist extensors are innervated by C6, C7 and C8 nerve roots and by the radial nerve, which innervates all of the extensor muscles in the upper and lower arm.1
II. Mobilizing - Increasing Range of Motion
III. Indications for Stretching
The most common condition that requires mobilizing and/or stretching of the wrist extensors is lateral epicondylalgia, more commonly known as “tennis elbow.”1 Repetitive activities that require a strong grip stress the common attachment site of the wrist extensors, which then causes pain during gripping, wrist flexion and forearm pronation. Stretching and mobilization of the wrist extensor muscles are used in the treatment, along with splinting, rest and ice, to help reduce inflammation and decrease stress on the lateral epicondyle region.1
Another condition that requires stretching of the wrist extensors is intersection syndrome, which affects individuals who do repeated wrist actions as in canoeing, weight lifting, or shoveling.2 This condition occurs when there is repetitive rubbing of extensor pollicis brevis and abductor pollicis longus over the extensor carpi radialis brevis and longus causing the tenosynovial lining around the extensor tendons to become inflamed and irritated.2 Pain is felt when the wrist is moved into flexion, especially toward the thumb, because the irritated extensor tendons are rubbing against the thumb muscles. Stretching is used in treatment of this condition, after healing of the inflamed area occurs, to lessen the amount of friction of the thumb muscles over the extensor tendons.2 If a tendon release surgery is needed, stretching of the extensor muscles will be done to increase ROM and to help the wrist tendons to glide easily underneath the thumb muscles.2
V. Potential Clinical Syndromes or Etiologies
The wrist extension exercises shown above, have been proven successful in decreasing pain from lateral epicondylitis by producing dense scar tissue in the area of the common attachment site.3 The new fibrous tissue that is created from these concentric and eccentric exercises make the common extensor tendon more resistant to damage.3 These exercises that help the tendon adapt to increased tension should be done along with wrist extensor stretches for a more well-rounded plan of treatment.
VI. Additional Wed Based Resources
1. Neumann DA. Wrist. In: Falk K, ed. Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation. 2nd ed. St. Louis, MO: Mosby/Elsevier; 2010:216-243.
2. Wrist Conditions | Intersection Syndrome | Houston Methodist Orthopedics & Sports Medicine in the Greater Houston Area, TX. Available at: http://www.methodistorthopedics.com/intersection-syndrome. Accessed November 28, 2014.
3. Finestone HM, Rabinovitch DL. Tennis elbow no more. Can Fam Physician 2008;54(8):1115-1116.
4. Water Exercises | UW Orthopaedics and Sports Medicine, Seattle. Available at: http://www.orthop.washington.edu/?q=patient-care/articles/arthritis/water-exercises.html. Accessed December 3, 2014.