Paralysis can be either partial or complete. Paralysis of both the arms and legs has been traditionally been called quadriplegia. Quadriplegia is paralysis caused by illness or injury to a human that results in the partial or total loss of use of all their limbs and torso.

Causes
The primary cause of quadriplegia is a spinal cord injury, but other conditions such as cerebral palsy and strokes can cause a similar appearing paralysis. The amount of impairment resulting from a spinal cord injury depends on the part of the spinal cord injured and the amount of damage done. Injury to the spinal cord can be devastating because the spinal cord and the brain are the main parts of the central nervous system, which sends messages throughout your body.
Quadriplegia is caused by damage to the brain or the spinal cord at a high level C1-C7 in particular.

Signs and Symptoms -
Although the most obvious symptom is impairment to the limbs, functioning is also impaired in the torso. This can mean a loss or impairment in controlling bowel and bladder, sexual function, digestion, breathing and other autonomic functions. Furthermore, sensation is usually impaired in affected areas. This can manifest as numbness, reduced sensation or burning neuropathic pain.
Secondarily, because of their depressed functioning and immobility, tetraplegics are often more vulnerable to pressure sores, osteoporosis and fractures, frozen joints, spasticity, respiratory complications and infections, autonomic dysreflexia, deep vein thrombosis, and cardiovascular disease.
Severity depends on both the level at which the spinal cord is injured and the extent of the injury.