Spinal cord injury is the most serious complication of spinal injury and can result in loss of movement and sensation below the plane of injury, including bowel and urinary function and erectile (male) function. The prognosis varies depending on the degree of spinal cord injury, and the following is an introduction to the grading of spinal cord injuries. Grade A (complete injury): below the neural plane of spinal cord injury, including the sacral segment S4 to S5 (saddle area) without any preservation of motor and sensory function. Grade B (incomplete injury): below the neural plane of spinal cord injury, including the sacral segment S4 to S5 area with preservation of sensory function, but without any preservation of motor function. Grade C (incomplete injury): below the neural plane of spinal cord injury there is preservation of motor function, but more than half of the key muscles below the neural plane of spinal cord injury have muscle strength less than grade 3. Grade D (incomplete injury): there is motor function preservation below the neural plane of spinal cord injury, and at least half of the key muscles below the neural plane of spinal cord injury have muscle strength equal to or greater than grade 3. Grade E (normal): normal sensory and motor function. This is a new revised version of the American Spinal Cord Injury Society’s 2000 classification of spinal cord injuries, and there is one point that should be brought to our attention: for Grade C or D patients, they must have preserved sensory or motor function in the sacral segment S4 to S5 (saddle area), which means that if they have no sensation or movement in the saddle area, they are in Grade A (excluding spinal cord concussion and spinal shock), regardless of whether their limbs some motor function remains. In addition, patients with grade C or D must have one of two things: (i) voluntary contraction of the anal sphincter; and (ii) preserved motor function in more than three segments below the motor level of the spinal cord injury neural plane. Then briefly introduce spinal cord shock and spinal cord shock: spinal cord shock refers to a transient state of functional inhibition after spinal cord injury. There are no obvious organic changes in the gross pathology, only a little edema under the microscope, and no destruction of nerve cells and nerve fibers is seen. The clinical manifestation is a delayed paralysis immediately after the injury below the plane of injury, and after a few hours to two days, the spinal cord function begins to recover without any neurological sequelae later. Spinal cord shock is a temporary and complete suppression of function that occurs when the spinal cord is severely traumatized and pathologically damaged, and is characterized by delayed paralysis, loss of all spinal cord reflexes, including pathological reflexes, and loss of diaphoresis. The systemic changes may include hypotension or decreased cardiac output, bradycardia, decreased body temperature and respiratory dysfunction. Spinal shock occurs immediately after the injury. It usually lasts 3 to 4 days in children and 3 to 6 weeks in adults. The lower the site of spinal cord injury, the shorter the duration of its duration. For example, the period of spinal cord shock in the lumbar and sacral segments is usually less than 24 hours. The appearance of the bulbocavernosal reflex or anal reflex or plantar-plantar reflex is a marker for the end of spinal shock. After the end of the spinal shock period, if there is still no movement and sensation below the plane of injury, it indicates a complete spinal cord injury.