What is the medical term for paralysis affecting both legs and the lower part of the body?

The correct term for paralysis affecting both legs and the lower part of the body is paraplegia. This condition typically results from damage to the spinal cord in areas that control the legs. The primary distinction of paraplegia is that it specifically pertains to the loss of motor function and sensation in the lower limbs, affecting the trunk and legs while leaving the arms and upper body largely unaffected.

Quadriplegia refers to paralysis that affects all four limbs, while hemiplegia affects one side of the body, usually due to a stroke or injury. Monoplegia, on the other hand, is the paralysis of a single limb. Each of these terms describes specific patterns of paralysis based on the affected body regions, which is why paraplegia is the accurate term for the condition described in the question.