Which term describes the loss of sensation or movement in the lower body?

The term that describes the loss of sensation or movement in the lower body is paraplegia. This condition generally occurs due to injury or disease affecting the spinal cord, particularly in the lower regions. As a result, individuals may experience a complete or partial loss of function and sensation in their legs and lower body.

In distinguishing this term from others, myositis refers to inflammation of the muscles, which does not specifically indicate a loss of sensation or movement affecting the lower body. Osteoporosis is a condition that weakens bones, making them more susceptible to fractures, but it does not directly relate to loss of sensation or movement. Polymyositis involves inflammation of multiple muscle groups, leading to muscle weakness primarily, but again, it doesn't specifically signify a loss of function localized to the lower body as seen in paraplegia. Thus, paraplegia accurately describes the specific condition outlined in the question.