{'fraction_non_alphanumeric': 0.025189924030387844, 'fraction_numerical': 0.008796481407437025, 'mean_word_length': 5.072815533980583, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
The Use of Ultrasound Imaging to Demonstrate Reduced Movement of the Median Nerve during Wrist Flexion in Patients with Non-Specific Arm Pain

It is with great interest that I read the article by Greening et al. (this issue), in which high-resolution ultrasound imaging was used to measure the movement of the median nerve at the wrist. Twelve patients with non-specific arm pain (diffuse arm pain, muscle weakness without atrophy, muscle tenderness and allodynia without specific signs of tissue inflammation) and 16 controls were assessed and results similar to those reported with magnetic resonance imaging (MRI) were found (Greening et al., 1999). Furthermore, it was shown that the ultrasound assessment of median nerve movement (MNM) correlated with the clinical assessment of nerve mobility by the upper limb tension tests (Butler, 1991), which apply tension to the brachial plexus and median nerve. The authors conclude that their technique of ultrasound imaging, which is less expensive than MRI, may be helpful in diagnosing non-specific arm pain, a condition for which there are no well-defined diagnostic tests at present. The study demonstrates that both transverse and antero–posterior movement of the median nerve in patients with non-specific arm pain is significantly reduced compared to a control-group. Although restricted nerve movement has also been observed in patients with carpal tunnel syndrome (Allmann et al., 1997), the authors considered it unlikely that carpal tunnel syndrome was the cause of the reduced mobility and arm pain in their cases as the cross-sectional area of the median nerve was not increased and the patients had not benefitted from steroid injections and wrist splinting. The authors postulate that their findings are ‘‘consistent with the hypothesis that multi-level minor nerve compression, due to muscle imbalance and postural abnormalities may be a cause of non-specific arm pain in office workers’’ (Novak and McKinnon, 1998; Greening and Lynn, 2000). They suggest that the loss of normal nerve mobility may lead to increased stresses being applied to the nerve by the adjacent tendons in the carpal tunnel causing nerve irritation. However, although the loss of normal nerve is demonstrated, the reason for this remains unknown. It has to be stated that tendons within the carpal tunnel are not in a position to apply increased stresses to the median nerve under normal conditions. However, our experience would suggest that the reduced values of