Types of Paralysis - Quadriplegia (Tetraplegia) and Paraplegia


Spinal Cord Injury Overview

When a person suffers a spinal cord injury, information traveling along the spinal cord below the level of injury will be either completely or partially isolated from the brain. This results in a condition called  tetraplegia (quadriplegia) or paraplegia.

Following a spinal cord injury the body will still be attempting to send messages from below the level of injury to the brain through the spinal cord known as sensory messages via sensory pathways (ascending tracts). The brain will also still be attempting to send messages from the brain to muscles throughout the body through the spinal cord via motor pathways (descending tracts). These messages however will be blocked by the damage in the spinal cord at the level of injury. Peripheral nerves joining the spinal cord above the level of spinal cord injury will be unaffected and continue to work as normal sending and receiving messages via the spinal cord to and from the brain.

Quadriplegia / Tetraplegia

Tetraplegia / Quadriplegia: is the medical term used when a person has a spinal cord injury above the first thoracic vertebra. Paralysis affects the cervical spinal nerves (C1-C8) resulting in paralysis in varying degrees in all four limbs. In addition to the arms and legs being paralysed, the abdominal and chest muscles will also be affected resulting in weakened breathing and the inability to properly cough and clear the chest. The older term Quadraplegic or Quadraplegia may also sometimes be used, mainly in the UK.


Paraplegia: is a term used when the level of spinal cord injury occurs below the first thoracic spinal nerve root (T1-S5). The degree at which the person is paralysed can vary from the impairment of leg movement, to complete paralysis of the legs and abdomen up to the nipple line. Paraplegics have full use of their arms and hands.

Cauda Equina Syndrome

Cauda Equina Syndrome: The cauda equina is the mass of nerves which fan out of the spinal cord at just below the first and second Lumbar region of the spinal cord, an area known as the conus medullaris. The spinal cord ends at L1 and L2 at which point a bundle of nerves travel downwards within the lumbar and sacral vertebrae. Injury to these nerves will cause partial or complete loss of movement and sensation to the legs, bladder, bowel and sexual organs. It is possible if the nerves are not too badly damaged for them to regenerate again and for the recovery of function. The resultant paralysis results in paraplegia, but this is also condition is refered to as a cauda equina syndrome injury.

Level of Spinal Cord Injury (Lesion)

The spinal cord injury level, otherwise known as a lesion, is the exact point in the spinal cord segment at which damage has occurred. The levels are determined by counting the nerves from the top of the spinal cord downwards, and these nerves are grouped into five different areas.

These levels are the cervical, thoracic, lumbar, sacral and coccygeal sections of the spinal cord as follows:

  • C1-C8
  • T1-T12
  • L1-L5
  • S1-S5
  • Coc1 - Sensation only

These areas are important in defining tetraplegia (quadriplegia) and paraplegia, as damage to the spinal cord at these points directly determines how groups of muscles, organs and sensations will be affected.

The remaining motor function, that is the voluntary ability for someone to contract a muscle, can be graded using a motor examination score. This score must be performed under special conditions with the limb held in a specific position to ensure no surrounding muscles can affect the results.

The motor score is graded in a six point scoring system as follows:

  • 0 = total paralysis.
  • 1 = palpable or visible contraction.
  • 2 = active movement, full range of motion (ROM) with gravity eliminated.
  • 3 = active movement, full ROM against gravity.
  • 4 = active movement, full ROM against gravity and moderate resistance in a muscle specific position.
  • 5 = (normal) active movement, full ROM against gravity and full resistance in a muscle specific position expected from an otherwise unimpaired person.
  • 5* = (normal) active movement, full ROM against gravity and sufficient resistance to be considered normal if identified inhibiting factors (i.e. pain, disuse) were not present.
  • NT= not testable (i.e. due to immobilization, severe pain such that the patient cannot be graded, amputation of limb, or contracture of >50% of the range of motion).

How the spinal cord has been damage is also a consideration when evaluating a spinal cord injury. There are two types of lesion, these are a complete injury and an incomplete injury. Someone with a complete injury will have complete loss of muscle control and sensation below their level of lesion. An incomplete injury is determined by a neurological examination where the diagnosis shows preservation of motor function, sensory function or random preservation of both.

The ASIA Impairment Scale (AIS) has been developed and is used in grading the degree of functional impairment:

  • A = Complete. No sensory or motor function is preserved in the sacral segments S4-S5.
  • B = Sensory incomplete. Sensory but not motor function is preserved below the neurological level and includes the sacral segments S4-S5, AND no motor function is preserved more than three levels below the motor level on either side of the body.
  • C = Motor incomplete. Motor function is preserved below the neurological level**, and more than half of key muscle functions below the single neurological level of injury have a muscle grade less than 3 (Grades 0–2).
  • D = Motor incomplete. Motor function is preserved below the neurological level**, and at least half (half or more) of key muscle functions below the NLI have a muscle grade >3.
  • E = Normal. If sensation and motor function as tested with the ISNCSCI are graded as normal in all segments, and the patient had prior deficits, then the AIS grade is E. Someone without a SCI does not receive an AIS grade.

Functionality after a Spinal Cord Injury

The degree to which a persons body will function following a spinal cord injury resulting in tetraplegia or paraplegia will depend on the level of injury, and whether the injury was complete of incomplete. In order to show what functionality may be possible following a complete spinal cord injury, we have put together the most common abilities for varying degree's of paralysis.

Click the spinal cord injury levels below for a comparison of complete injury levels and abilities

These abilities are not definitive, and slight variations may be present due to body weight, existing medical issues and post injury ageing.

Incomplete Spinal Cord Injuries

Anterior Cord Syndrome

Anterior Cord Syndrome: is when the damage is towards the front of the spinal cord, this can leave a person with the loss of motor function, impaired ability to sense pain, temperature and touch sensations below their level of injury. Pressure and joint sensation may be preserved. It is possible for some people with this injury to later recover some movement if motor recovery is evident days after the initial injury.

Central Cord Syndrome

Central Cord Syndrome: is when the damage is in the centre of the spinal cord. This typically results in the loss of function in the arms, but some leg function may be preserved. There may also be some control over the bowel and bladder. It is possible for some recovery from this type of injury, usually in the legs, gradually progressing upwards.

Posterior Cord Syndrome

Posterior Cord Syndrome: is when the damage is towards the back of the spinal cord. This type of injury may leave the person with good muscle power, pain and temperature sensation, however they may experience difficulty in coordinating movement of their limbs.

Brown Sequard Syndrome

Brown-Séquard syndrome: is when damage is towards one side of the spinal cord. This results in impaired or loss of movement to the injured side, but pain and temperature sensation may be preserved. The opposite side of injury will have normal movement, but pain and temperature sensation will be impaired or lost.

  • Difference between paraplegia and tetraplegic (quadriplegia)