a condition caused by osteoporosis in which the shoulders are rounded and the spine becomes prominently bowed, forming a hump in the upper back
See dowager's hump in American Heritage Dictionary 4
noun
An abnormal curvature of the spine that is primarily manifested as a rounded hump in the upper back. Typically affecting older women, the curvature is a result of collapse of the spinal column, caused by osteoporosis.