Massage Today
January, 2013, Vol. 13, Issue 01

Solving a Client Puzzle

How To Know Whether It's Tennis Elbow Or Nerve Entrapment

By Whitney Lowe, LMT

Suppose a client comes to see you complaining of lateral elbow pain. She reports that the pain has been going on for quite some time despite efforts to treat it. A first consideration might be that the client has lateral epicondylitis, commonly known as tennis elbow; not an unreasonable assumption since lateral epicondylitis is a common problem. However, it's also entirely possible that the client's complaint derives from another condition called radial tunnel syndrome.

The most effective results occur when you choose treatment techniques whose physiological effects best address the client's existing complaint. Conditions and treatment techniques both have physiological effects, which are the specific ways in which tissues respond either to the pain/injury or the intervention. Treating a client suffering from radial tunnel syndrome with techniques appropriate for someone suffering from lateral epicondylitis would aggravate the problem rather than help it. So, let's take a look at these two problems and explore how one might mistake radial tunnel syndrome for lateral epicondylitis.

Exploring the Conditions

Most people are aware that lateral epicondylitis is a chronic overuse condition affecting the common extensor tendons where they attach at the lateral epicondyle of the humerus. Despite the implication from its name, because it ends in –itis, epicondylitis is rarely an inflammatory problem and is not caused by the common explanation of torn tendon fibers. Instead, it is caused by collagen degeneration in the extensor tendons. Pain is most pronounced where the tendons attach at the lateral epicondyle of the humerus.

wrist extension Figure 1: Resisted wrist extension with palpation. Epicondylitis presents several clear signs and symptoms that can be picked up during the evaluation process. There is likely to be pain with palpation of the extensor tendons and it is likely to be particularly tender where they attach at the lateral epicondyle. It is also common for pain to be reproduced when stretching the extensor tendons by moving the wrist into full flexion. Resisted wrist extension also reproduces the client's pain, especially if the affected tendons are palpated during the resisted wrist movement. (See Figure 1)

Unlike lateral epicondylitis, radial tunnel syndrome is not as common. However, when present, it can easily be confused with epicondylitis. Radial tunnel syndrome is frequently called resistant tennis elbow, because the symptoms are very similar to tennis elbow and they persist even after attempts at treatment (usually for lateral epicondylitis).

elbow region Figure 2: View of the elbow region showing divisions of the sensory and motor branches of the radial nerve. (3D anatomy images.) Copyright of Primal Pictures Ltd., www.primalpictures.com. In the elbow region, the radial nerve divides into a superficial sensory branch and a deep motor branch. The primary problem in radial tunnel syndrome is compression of these branches as they course through fibro-osseous tunnels created by surrounding muscles, ligaments and bones. The deep motor branch innervates the wrist extensor muscles and is called the posterior interosseous nerve (PIN). Compression of the PIN most commonly causes weakness or atrophy in the wrist extensors because the PIN contains motor fibers almost exclusively. However, pain similar to lateral epicondylitis is possible because the superficial sensory branch of the radial nerve may also be compressed in this region. (See Figure 2)

Nerve compression occurs in radial tunnel syndrome where the PIN courses under the supinator muscle. The archway created by the edge of the supinator muscle under which the PIN passes is called the Arcade of Frohse. (See Figure 3) The Arcade of Frohse often has fibrous bands that compress the nerve causing the tunnel compression syndrome. These fibrous bands are small and deep under the extensor muscle mass, so they are challenging to palpate.

Arcade of Frohse Figure 3: Arcade of Frohse. (3D anatomy images.) Copyright of Primal Pictures Ltd., www.primalpictures.com. Although radial tunnel syndrome and lateral epicondylitis may initially present with similar symptoms, there are some key aspects of assessment that will help differentiate the problems. Lateral epicondylitis is most likely to cause pain during resisted wrist extension. Radial tunnel syndrome, on the other hand, is more likely to present with less pain but significant weakness during resisted wrist extension because it is the PIN motor fibers that are most affected.

Pain can be reproduced during palpation with both these conditions. However, when palpating the lateral elbow region, radial tunnel syndrome pain is more likely to be felt somewhat distal to the epicondyle in the soft tissues. Epicondylitis pain is predominantly in the extensor tendons and right at the epicondyle. In addition, pain arising from nerve compression in radial tunnel syndrome is likely to be less specific and extend into the forearm. Epicondylitis pain is usually far more local right at the proximal extensor tendon group and their attachments.

Treatment Considerations

Based on her initial symptoms, our client could have either one of these conditions. This is a great illustration of why it is so important to perform a thorough assessment and not immediately jump to conclusions. Assuming she has lateral epicondylitis, the most likely treatment approach would include deep transverse friction of the common extensor tendons. The physiological effects of this treatment technique (stimulation of fibroblast activity which encourages collagen rebuilding) would match the physiology of the tissue injury (collagen degeneration). The friction technique would be valuable in addressing the chronic tendon degeneration of epicondylitis.

However, if the primary problem is radial tunnel syndrome, applying deep friction could significantly aggravate the problem by placing adverse pressure on the nerve. For radial tunnel syndrome it would be far more important to address muscular hypertonicity throughout the wrist extensors and the supinator muscle so they don't further compress the nerve. In addition, neural mobilization techniques for the radial nerve would encourage full freedom of movement of the nerve and eventually reduce symptoms. Neural mobilization engages gentle pulling actions during certain motions of the upper extremity that encourage smooth and free gliding of the nerve near any adjacent structures.

This case illustrates two very important points that will make your treatments more successful. It is valuable to know about soft-tissue pathologies in order to be able to distinguish between conditions. In addition, in cases like this, it is possible to make treatment errors that make a client's condition worse. Performing accurate assessment and considering the physiological effects of the treatment on the specific tissues being treated will make your treatments far more effective and successful.

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