Paralysis means a person cannot move one or more of their muscles.
Paralysis isn't due to problems with the muscles themselves, but results from conditions affecting the nerves and spinal cord that carry movement messages from the brain.
Depending upon the cause, paralysis may affect a specific muscle group or region of the body (localised), or a larger area may be involved (generalised).
Common causes of paralysis include stroke, head injuries, spinal cord injuries and multiple sclerosis.
When only one limb is affected it is called monoplegia, and when an arm and a leg on one side of the body is affected the condition is known as hemiplegia. When only the lower limbs are affected by paralysis it is called paraplegia, and when all four limbs are affected it is referred to as tetraplegia or quadriplegia. The term palsy is sometimes used to refer to the loss of muscle power in a body part, such as Bell's palsy affecting the face.
Diagnosis of paralysis will be based on a person's symptoms, physical examinations and other tests, including scans and nerve tests.
If a person's paralysis is permanent, it cannot be cured, but efforts will be made to help the person to be as independent as possible through mobility aids and adaptations.
In some cases where legs and arms are affected by paralysis, neuroprosthesis devices that stimulate muscles with electrical currents may help regain some movement. However, these devices are expensive and may not be suitable for all cases of paralysis.