Dropped shoulder syndrome: a cause of lower cervical radiculopathy.

BACKGROUND AND PURPOSE

Cervical radiculopathy is a pathological process involving a nerve root of the cervical spine. The most common causes of radiculopathy are cervical disc herniation followed by cervical spondylosis. The aim of this study was to determine the effect of dropped shoulder as a cause of lower cervical radiculopathy.

METHODS

In total, 132 patients, comprising 105 women (79.5%) and 27 men (20.5%; female : male ratio of 4 : 1) and a mean age of 36.7 years (range 18-58 years), were included in this study. All of the patients presented with shoulder pain, and were investigated by cervical X-ray, cervical magnetic resonance imaging, serum muscle enzymes, and electromyography (EMG)/nerve-conduction studies.

RESULTS

Ninety six patients (72.7%) exhibited visually detectable dropped shoulder. The lateral view X-ray of the cervical region revealed eight or more vertebrae. In 119 patients (90.2%), the EMG revealed a mild-to-moderate or moderate denervation patterns in the abductor digiti minimi, first dorsal interosseous, and flexor carpi ulnaris muscles, while the abductor pollicis brevis, extensor carpi radialis, and triceps brachii were denervated in 102 patients (77.3%). All of the patients had lower cervical paraspinal muscles with a denervation pattern.

CONCLUSIONS

Three criteria for diagnosing dropped shoulder syndrome have been suggested: pain with consistent anatomical distribution, X-ray abnormalities, and EMG abnormalities. Compression of the cervical roots by muscle spasm has been proposed as the cause of dropped shoulder syndrome; this possibility is discussed herein.