Bent spine syndrome.

Eight elderly patients developed progressive paravertebral muscle weakness with bent spine on standing but normal supine posture. Computed tomography showed pronounced hypodensity of the paraspinal muscles. Serum creatine kinase was moderately increased, paraspinal EMG non-specific, and biopsy myopathic. The syndrome was familial in two patients and may be caused by a late onset paraspinal muscle dystrophy. In the absence of specific pathological changes, such cases could be classified as having "bent spine syndrome".