Which condition is characterized by complete paralysis of all four limbs?

Quadriplegia is the condition characterized by complete paralysis of all four limbs, which includes both the arms and the legs. This condition typically results from a spinal cord injury or a neurological disorder that affects the upper motor neurons in the spinal cord. When the spinal cord is damaged at a high level, usually in the cervical region, the communication between the brain and the limbs is disrupted, leading to loss of motor function and sensation in all four limbs.

In contrast, hemiplegia refers to paralysis affecting only one side of the body, often resulting from a stroke or injury to one hemisphere of the brain. Paraplegia involves paralysis of the lower limbs and is often the result of injury to the thoracic, lumbar, or sacral regions of the spinal cord. Aphasia, while a serious condition impacting communication ability, does not specifically involve paralysis of limbs; it affects language processing in the brain. Understanding these distinctions helps clarify why quadriplegia is the correct designation for paralysis affecting all four limbs.