A spinal cord injury at which levels typically results in quadriplegia?

Quadriplegia, also known as tetraplegia, results from an injury to the cervical region of the spinal cord. When the spinal cord is damaged at levels C1 through C8, it affects all four limbs and usually results in varying degrees of paralysis and loss of motor function in both the arms and legs.

The cervical spine consists of eight vertebrae, and injuries at these levels can compromise the signals from the brain to the body. This can lead to complete loss of function below the level of injury, which is characteristic of quadriplegia. The higher the injury occurs within this range, such as at C1 or C2, the more severe the impairment tends to be, potentially affecting respiratory function as well.

In contrast, injuries to the thoracic levels (T1 to T12) and lumbar levels (L1 to L5) do not lead to quadriplegia. Instead, these injuries typically result in paraplegia, which affects the lower body and limbs but preserves some motor function in the upper limbs, as the cervical spinal cord remains intact. Thus, the correct choice indicating levels that result in quadriplegia is the one referring to C1 to C8.