Mention upper extremity nerve entrapment problems and the first thing that comes to most people’s minds is carpal tunnel syndrome (CTS). It is the most commonly occurring and well-studied peripheral nerve entrapment condition. Women develop the condition more often than men, and the incidence of the condition is much higher in certain occupations—especially those with significant upper extremity overuse.
Workers whose jobs involve high-velocity and high-force manual labor are far more susceptible to CTS, and it is especially common when the occupation involves vibrating tools, assembly-line work, or other types of challenging upper extremity repetitive motion.1 Massage therapists are also susceptible to this problem because of the significant hand and finger grasping involved in daily work.
Clients are increasingly looking for nonsurgical treatments for this chronic condition, as there is still a moderately high number of unsuccessful carpal tunnel surgeries. One study noted that the failure rate for CTS surgery can sometimes run as high as 25 percent.2 Because traditional treatment is often unsuccessful, many people seek the care of complementary treatment approaches such as massage therapy to address this problem. As a result, massage therapists have a much more important role in evaluating the nature and severity of nerve pathology in these cases.
Massage therapists must rely on a physical examination to evaluate potential nerve-related injury. Thus, the results from assessment are even more important. In this installment, we’ll take a look at the biomechanical and physiological factors that lead to carpal tunnel problems and then explore some innovative ways to make standard physical examination procedures even more effective for identifying potential problems.
Physiological Effects of Nerve Compression
CTS and other peripheral entrapment neuropathies result from numerous causes. The most common are pressure on the nerve from adjacent muscles, tissue fluid accumulation from swelling, fibrosis, space-occupying lesions, direct compression of the nerve from outside forces, and neural ischemia. These factors can be interrelated and an increase in one routinely affects the others. An example is the relationship between pressure on nerves and the reduction in neural blood flow (neural ischemia).
Pressure on nerves reduces circulation of blood through very small blood vessels directly to the nerve tissue. In some cases, the alteration in blood flow can produce an inflammatory response that increases pressure on the nerve due to local tissue fluid accumulation. The pressure-neural, ischemia-inflammatory response becomes a vicious cycle that increases neurological symptoms.
Intraneural blood-flow problems can also cause pain in nerves without causing significant changes in the nerve conduction velocity.3 However, the most preferred high-tech diagnostic tool for validating the presence of CTS is a nerve conduction velocity test. The limitations of these tests suggest that other forms of evaluation, such as a comprehensive physical examination, play a crucial role in accurate identification of nerve compression pathologies. A detailed clinical history is also crucial because physiological changes associated with neural ischemia could be magnified in a client with some other form of circulatory compromise, such as diabetes.
CTS is usually described as a condition associated with chronic or long-term compression of the median nerve. However, some of the degenerative processes described above can occur after only a short period of time. The time frame for detrimental impacts may even be as short as minutes or hours, depending on the biomechanical stresses on the nerve. The cumulative effects of time is another challenge. The longer pressure is applied to neural structures, the greater the potential damage and the more sensitive the tissues will become. In fact, very little pressure is needed to elicit symptoms if that pressure is applied for a long period of time.
Client symptoms from CTS vary based on a number of factors related to structure and function of the affected nerve. The median nerve is a mixed nerve, meaning it contains both sensory and motor fibers. However, at the level of the carpal tunnel, there is a higher percentage of sensory fibers in the median nerve. The sensory fibers are also distributed more dominantly in the periphery of the nerve (Image 1). As a result, compression pathology tends to produce sensory symptoms (pain, paresthesia, numbness) earlier than motor symptoms (atrophy and weakness) because the sensory fibers are closer to the periphery of the nerve. This fiber distribution pattern also indicates that if there is significant grip-strength weakness along with sensory symptoms, the condition may be more advanced because a greater number of motor fibers are affected.
Variations on Common Evaluation Methods
Despite the frequency and prevalence of CTS, there are no high-tech diagnostic procedures that produce a definitive diagnosis for the condition. Nerve conduction velocity is still used frequently as a means for identifying median nerve impairment. However, early sensory symptoms can occur without a significant change in nerve conduction velocity. Because the neural pathology and sensory symptoms may occur without significant impairment of conduction velocity, there is even greater importance placed on the physical examination to identify potential neural involvement in the early stages.
Another potential complication that often clouds the picture of CTS involvement is locating the precise region of median nerve entrapment. While the carpal tunnel is certainly the most researched and well-known region of median nerve pathology, there are numerous locations throughout the upper extremity where the median nerve can be compressed. These locations include the region between the scalene muscles and beneath the clavicle in the thoracic outlet, beneath the pectoralis minor muscle, under the bicipital aponeurosis in the elbow, and between the two heads of the pronator teres muscle in the forearm. Compression of median nerve fibers in any of these locations could mimic the symptoms of compression at the carpal tunnel in the wrist. For that reason, detailed physical examination is, again, even more important.
Massage therapists are in an ideal position to address not only carpal tunnel compression, but also the numerous sites of nerve compression throughout the upper extremity. However, it takes skilled clinical reasoning and sharply honed physical examination skills to identify the most likely site(s) of nerve compression.
I cannot emphasize enough how important skillful clinical reasoning is for making some of these determinations. All too often I hear massage practitioners say they don’t use any type of formal assessment process but let their hands tell them where to work. While your palpation skills are unquestionably valuable for identifying hypertonicity in muscles, they are notably limited for identifying nerve compression pathology. Nerve compression and tension symptoms are notoriously tricky and can often deviate from simple evaluation guidelines. So, the more information we can gather about the median nerve involvement, the greater our chance of being accurate to set an effective course for our treatment.
There are a number of special orthopedic tests that are routinely used to evaluate CTS. Some of them are more accurate than others. Any evaluation procedure has two key components to determine how accurate it is at identifying a particular type of tissue involvement: sensitivity and specificity. Sensitivity refers to how accurate that test is at determining everyone who has the particular problem being investigated. Specificity refers to how accurate the test is at ruling out everyone who does not have that problem. Ideal accuracy for any evaluation procedure comes when you have a high degree of both specificity and sensitivity.
One of the problems that occurs, especially in the early onset stages of CTS, is that many of the standard orthopedic testing procedures are not sensitive enough to pick up sensory symptoms that indicate nerve pathology. Modifications can be made to some of the standard CTS orthopedic assessment tests to make them more sensitive, and consequently more versatile, for evaluating nerve compression pathologies.
Variations on standard carpal tunnel evaluation procedures are suggested here. When performing any of these procedures, remember that exaggerated neural sensations may be indicative not only of mechanical compression neuropathy, but could involve other facets of neural sensitivity, such as excess neural tension or systemic neurological disorders like diabetes. Appropriate contraindications for proper treatment should be carefully weighed after gathering evaluation information.
Phalen’s Test
Phalen’s test is the most common special orthopedic test for evaluating CTS. To perform this test, the client presses the back of the hands together so the wrists are flexed close to 90 degrees (Image 2). If the sensory symptoms of pain, paresthesia, or numbness in the median nerve distribution are reproduced within about 60 seconds, the test is considered positive for median nerve compression in the carpal tunnel.
Neurological symptoms are increased with the Phalen’s test because holding the wrist in flexion increases compression in the carpal tunnel region. However, the standard Phalen’s test position of using both hands at the same time with the elbows flexed decreases tensile forces on the remainder of the median nerve. If the nerve is pulled taut, less pressure on the nerve is required in the carpal tunnel region for symptoms to appear.
Greater sensitivity for this test can be achieved by holding the wrist in the Phalen’s test position while the upper extremity is held in a position that increases neural tension on the remainder of the median nerve. This position includes lateral flexion of the neck to the opposite side, shoulder abduction, elbow extension, and wrist flexion (Image 3). This test would be performed unilaterally, unlike the standard Phalen’s test, which is performed bilaterally.
Carpal Compression and Pressure Provocative Tests
Applying a moderate amount of direct pressure to the median nerve at the carpal tunnel with both thumbs is called the carpal compression test (Image 4). If symptoms arise within about 20–30 seconds, the test is considered positive for median nerve compression. This test is considered pretty accurate. A suggested modification of this procedure is called the pressure provocative test. It includes elbow extension, forearm supination, and about 60 degrees of wrist flexion along with pressure over the carpal tunnel.
The pressure provocative test could be enhanced with increased tension on the median nerve by using the upper extremity median nerve stretch position described with the Phalen’s test. The position would include lateral neck flexion to the opposite side, shoulder abduction, elbow extension, forearm supination, and partial wrist flexion. Pressure would then be applied to the carpal tunnel while the arm is in this position (Image 5).
Hand Elevation Test
Another relatively new evaluation procedure that has demonstrated greater accuracy than the Phalen’s test is the hand elevation test. In this procedure, the client holds the hand as high as comfortably possible overhead (Image 6). If neurological symptoms in the median nerve distribution of the hand are reproduced within one minute, the test is considered positive.
This test could be made more sensitive by adding additional neural tension to the median nerve with the hand and arm elevated. With the arm held overhead, the neck would then be laterally flexed to the opposite side. Additional tension on the median nerve is added by putting the wrist in extension (Image 7). Another variation would be keeping the wrist in flexion (as in the Phalen’s test wrist position).
Tethered Median Nerve Stress Test
An evaluation test that is now being used with increasing frequency is the tethered median nerve stress test. Some degree of neural tension is already a component of this test. The wrist is held in extension and supination. While in this position, the index finger is pulled into hyperextension as far as motion allows. The finger movement can be performed by the practitioner or by the client. If neurological symptoms are felt within about one minute, the test is considered positive.
Additional neural tension can be added to the proximal upper extremity to make this procedure more sensitive. Positions to add include lateral neck flexion to the opposite side, shoulder abduction, elbow extension, and forearm supination (Image 8). Note that not all of these motions need to be added. In some cases, symptoms will be exacerbated with the addition of just one position. This may also be helpful for identifying other potential regions of median nerve entrapment. For example, if symptoms are particularly aggravated when elbow extension is added, there is an increased likelihood that some nerve binding or restriction around the elbow or forearm is involved.

More effective results
Clients are increasingly using massage therapists to address a wide variety of soft-tissue disorders like carpal tunnel syndrome. Because we do not rely on high-tech diagnostic procedures, and in many cases, they are not accurate, the physical examination methods we use are increasingly valuable. While some practitioners may be familiar with these standard evaluation procedures, using effective clinical reasoning to modify them in ways that make them more sensitive increases their value and makes your assessment even more accurate. With a better understanding of the primary location of nerve pathology, we can most accurately direct treatment for more effective results.

Notes
1. A. Kozak et al., “Association Between Work-Related Biomechanical Risk Factors and the Occurrence of Carpal Tunnel Syndrome: An Overview of Systematic Reviews and a Meta-Analysis of Current Research,” BMC Musculoskeletal Disorders 16 (2015): 231. doi:10.1186/s12891-015-0685-0.
2. V. Neuhaus et al., “Evaluation and Treatment of Failed Carpal Tunnel Release,” Orthopedic Clinics of North America 43, no. 4 (2012): 439–47. doi:10.1016/j.ocl.2012.07.013.
 3. M. Shacklock, Clinical Neurodynamics (Elsevier, 2005).

Whitney Lowe is the developer and instructor of one of the profession’s most popular orthopedic massage training programs. His texts and programs have been used by professionals and schools for almost 30 years. Learn more at www.academyofclinicalmassage.com.