This article is only available in the PDF format. Download the PDF to view the article, as well as its associated figures and tables. Porosity of bone is a frequent sequel in many pathologic states. It may be found in a single bone or in many bones in the same patient. It is, however, seldom a primary lesion causing local pain and deformity. The etiology of atrophy of bone is usually apparent, and can be classified readily under one of the following headings: (1) disuse, (2) neurogenic, (3) endocrinologic or (4) nutritional. The case reported here is unusual because: 1. The atrophy of bone was limited to the spinal column and pelvis. 2. The etiology was obscure. 3. The softening of the vertebral bodies resulted in a painful posterior curvature of the spine. 4. Rest on a convex frame yielded complete relief. REPORT OF A CASE Mrs. Rose Y., 65 years old, was admitted to my service at the Israel Zion Hospital, Brooklyn, because of increasing pain and deformity of her back. She had