Hyperactive pectoralis reflex as an indicator of upper cervical spinal cord compression. Report of 15 cases.

Myelopathy from cervical spondylosis is often accompanied by hyperreflexia of the upper-extremity deep tendon reflexes (DTRs). Reflexes such as the pectoralis jerk and the deltoid jerk may only be apparent in the context of hyperreflexia. Although the nerve roots involved in the reflex arcs are well described, levels of cervical spinal cord compression that lead to the hyperreflexia are not as clear. This is of particular significance for patients with multilevel cervical spondylosis in determining the levels responsible for their symptoms. The authors examined 15 consecutive patients who presented for treatment of cervical myelopathy. The clinical examination was then correlated with levels of cervical spinal cord compression by cervical magnetic resonance imaging or computerized tomography with intrathecal contrast enhancement. The presence of a prominent pectoralis jerk was seen only in patients with spinal cord compression at the C2-3 and/or C3-4 levels (nine patients). No patient with compression at or below the C4-5 disc space without coexisting compression at a higher level had hyperactive pectoralis reflexes. This association between the C3-4 level and a hyperactive pectoralis reflex was significant (p < 0.004, Fisher's exact test). The deltoid reflex was tested in the last nine consecutive patients. It was present in patients with compression of the upper spinal cord at levels C3-4 and C4-5 (four of five patients) but appeared in only one of four patients with compression below C4-5. This association did not attain statistical significance. The presence of a hyperactive pectoralis reflex is specific for lesions of the upper cervical spinal cord. Examination of upper-extremity DTRs may be helpful in planning the appropriate levels for surgical decompression in patients with multilevel spondylosis and myelopathy.