Paralysis (pah-RAHL-uh-sis) is the inability to consciously control the movement of the muscles.

Nico's Story

Nico Fiorello was 17 years old in May 2015 when he dove into a patch of murky water at Jones Beach on New York's Long Island. Nico hit his head on a hidden sandbar below, breaking his neck and causing one of the broken bones to pierce his spinal cord. Nico was almost completely paralyzed; the only movement he was capable of below his neck was wiggling his toes. Surgeons inserted rods to fuse Nico's vertebrae back together, but his future did not look hopeful. Doctors estimated only 10 percent of people with neck injuries as severe as Nico's ever regained the ability to walk again. However, after just four months of intense physical therapy, Nico was able to take a few steps unassisted and spoke of joining his school's lacrosse team the following spring.

Left to right: Spinal cord showing regions (cervical, thoracic, lumbar, etc.) and nerves; hemiplegia; paraplegia; and quadriplegia. The gray shading indicates how much of the body is paralized.

Left to right: Spinal cord showing regions (cervical, thoracic, lumbar, etc.) and nerves; hemiplegia; paraplegia; and quadriplegia. The gray shading indicates how much of the body is paralized.
Illustration by Frank Forney. © 2016 Cengage Learning®.
“Like a Mind in a Jar”

Jean-Dominique Bauby (1952–1997), editor of the magazine Elle, was 43 years old and had a wife and two young children when he suffered a stroke that left him with a condition called locked-in syndrome. Bauby was able to think, but he could not speak or move a single muscle in his body except for his left eye. He began to communicate by blinking his eye in a kind of code that a friend painstakingly transcribed letter by letter, first into words and then into sentences. The sentences became a book titled The Diving Bell and the Butterfly. The book was an instant best seller in France and later inspired readers worldwide.

What Is Paralysis?

Muscle is a special kind of tissue that enables bodies to move. It is under the control of the nervous system, which processes messages to and from all parts of the body. To understand paralysis, it is important to understand certain terms. Motor neurons are those nerve cells that stimulate the muscles that are under conscious control, such as those for walking, swallowing, breathing, and talking. The usual pathway through which nervous signals are sent involves transmission of impulses from the upper motor neurons of the brain to the lower motor neurons of the brain stem * and the spinal cord and then on to the actual muscles. Paralysis occurs when either the upper or the lower motor neurons are irrevocably damaged through either disease or injury and the individual loses the ability to move the muscles voluntarily.

There are several different kinds of paralysis. Monoplegia occurs when only one limb, generally the arm, is paralyzed. In diplegia, either both arms or both legs are paralyzed. Paralysis of the muscles of the face, arm, and leg on one side of the body is called hemiplegia (“hemi” means “half”) and usually results from damage to the opposite side of the brain, which occurs because the upper motor neurons cross from one side of the brain to the other within the brain stem. Damage to the nerves of the spinal cord affects different parts of the body, depending on the amount of damage and where it occurred. Paralysis of both lower limbs is called paraplegia, and paralysis of both arms and both legs is called quadriplegia (or tetraplegia). Spastic paralysis refers to a form of paralysis that often occurs due to upper motor neuron disease or injury. In spastic paralysis, the muscles are continuously contracted and tight. The individual may experience twitches and muscle spasms. Flaccid paralysis refers to a form of paralysis that often occurs due to lower motor neuron disease or injury. In flaccid paralysis, the muscles get no input from the central nervous system * , and they remain floppy, loose, and limp.

Paralysis may be temporary or permanent, depending on the disease or injury. Because paralysis can affect any muscle in the body, a person may lose not only the ability to move but also the ability to talk or to breathe unaided.

How Does a Person Become Paralyzed?

Physical injury (such as through sports or car accidents) is often the cause of paralysis. Approximately 37 percent of spinal cord injuries are caused by motor vehicle accidents. Acts of violence, sports injuries, and falls are other causes. Around 12,000 Americans are the victims of a spinal cord injury every year, the majority of whom are men (80 percent).

Certain disorders and conditions also cause paralysis. Defects in the developing brain of the fetus *

Guillain-Barré (gee-YAN ba-RAY) syndrome is an autoimmune disorder in which the body's own cells attack the insulation and core of the nerve fibers, beginning in the hands and feet. In myasthenia gravis (myes-THEE-nee-a GRA-vis), another autoimmune disorder, a chemical malfunction disrupts the communication needed for muscles to contract. In 2014 and 2015 doctors were baflied by a rash of unexplained flaccid paralysis in over 100 children in 34 states in the United States. Some doctors believed that a respiratory illness known as EV-D68 might be responsible, as an outbreak of this disease occurred at the same time as the cases of paralysis, but this was not conclusively proven. In October 2015 the Centers for Disease Control and Prevention (CDC) put forth the possibility that a different virus, EV-C105, might be responsible. EV-C105 is in the same family of viruses as polio, which caused paralysis in tens of thousands of children in the mid-1900s before the disease was halted through an intense vaccination effort. Research into the cause of the new paralysis cases was ongoing as 2015 drew to a close.

Other causes of paralysis include poisoning, infection, blocked or burst blood vessels, and tumors. In rare cases, no physical cause for paralysis can be found. Psychologists call this condition a conversion disorder; that is, a person converts his or her psychological anxiety into physical symptoms of paralysis, but nerve and muscle function are still intact.

Signs and Symptoms

The signs and symptoms of paralysis vary depending on the cause of the paralysis. When the spinal cord is crushed, as in Nico's injury, a person is immediately paralyzed and loses feeling in the affected limbs. But the full extent of the injury cannot be identified for up to three weeks after the injury. Upon injury the spinal cord and associated tissues swell. This swelling extends above and below the site of injury. In a few weeks when the swelling subsides, the true injury and resultant paralysis will be known.

When damage to the muscles or central nervous system is caused by a progressive disease or disorder, such as muscular dystrophy or multiple sclerosis, symptoms are gradual and often start with muscle fatigue and weakness. With poliomyelitis (po-lee-o-my-uh-LYE-tis) and stroke, paralysis comes on suddenly, with little or no warning.

Actor and director Christopher Reeve was paralyzed in an equestrian competition in 1995. Reeve raised public awareness about spinal cord injury and the significance of medical research to help people with disabilities.

Actor and director Christopher Reeve was paralyzed in an equestrian competition in 1995. Reeve raised public awareness about spinal cord injury and the significance of medical research to help people with disabilities. He died at age 52 on October 10, 2004, of heart failure.
Superman in More Ways Than One

Many people might remember the actor Christopher Reeve as Superman in the feature film in 1978. While participating in a horse jumping competition in 1995, Christopher was thrown from his horse and landed on his head. Although he was wearing a helmet and a protective vest at the time, Christopher sustained complex fractures to the first and second cervical vertebrae, requiring life-support interventions to remain alive. After a long rehabilitation course, Christopher was able to power a wheelchair through the use of a breathing tube and even regained occasional sensation in parts of his body. He became active in stem cell research for spinal cord regeneration.


Information about symptoms and their onset helps the doctor pinpoint the cause of paralysis. With certain genetic * * (CT) or MRI * scans.

Is Paralysis Treatable?

Aside from poliomyelitis (which can be prevented by vaccination * ) and brain and spinal cord injuries (which in some cases can be prevented by using appropriate safety measures), it is usually not possible to prevent the conditions that cause paralysis, and most of the time there is no specific treatment. Steroid medications are sometimes given at the time of spinal cord injury to reduce inflammation in an attempt to limit the amount of damage to the spinal nerves. Upon arrival to the emergency room after a spinal cord injury steroids will be given immediately. The steroids help reduce the inflammation in the spinal cord, reducing the damage to the cord. Steroids cannot reverse the spinal cord damage but help to prevent the damage from extending above and below the site of injury.

Patients with myasthenia gravis may be offered a drug that helps their muscles contract. Most people with Guillain-Barré syndrome recover on their own. Conversion disorder can be difficult to treat; the underlying psychological problem must be addressed.

Living with Paralysis

Many people with paralysis have normal life spans, even when the condition is the result of progressive disease. People who are confined to wheel-chairs can still drive, swim, fly planes, and even ski. But being paralyzed requires major adjustments to daily living. For people with paralysis who must use wheelchairs, treatment emphasizes exercises and special care to avoid infections and pressure sores. Standing wheelchairs, which allow a paralyzed person to rise to a standing position, can also help with these issues. For people with severe paralysis, ordinary body functions such as urinating and having bowel movements may be difficult tasks. In extreme cases, a person may not even be able to breathe without assistance. Help is available to cope with most cases of paralysis, and people with this condition can often hold jobs, raise families, and participate in various activities.

Will There Ever Be a Cure?

In the mid-1990s no one would have imagined that badly injured nerves could heal. But due to medical advances being made in the 21st century, people may be able to regain the function they have lost through injury to their motor nerves. For example, experiments with rats and cats have shown that it is possible to repair damaged nerves and that severed spinal cord tissue can be made to grow back. Of course, many questions need to be answered before these approaches can be applied to humans.

See also Birth Defects: Overview • Cerebral Palsy • Guillain Barré Syndrome • Infection • Lou Gehrig's Disease (Amyotrophic Lateral Sclerosis) • Multiple Sclerosis (MS) • Muscular Dystrophy • Myasthenia Gravis • Spinal Cord Injury • Stroke


Books and Articles

CBS News. “Teen Paralyzed in Swimming Accident Walks Again.” (accessed March 7, 2016).

Maddox, Sam. Paralysis Resource Guide. Short Hills, NJ: Christopher & Dana Reeve Foundation, 2015.

Milmo, Cahal. “Paralysed Man Darek Fidyka Walks Again after Treatment by British Doctors on ‘Brink’ of Cure for Paralysis.” The Independent. (accessed March 7, 2016).

Walsh, Fergus. “Paralyzed Man Walks Again After Cell Transplant.” BBC News. (accessed March 7, 2016).


Centers for Disease Control and Prevention. “Acute Flaccid Paralysis Associated with Novel Enterovirus C105.” (accessed March 7, 2016).

MedlinePlus. “Spinal Cord Injuries.” U.S. National Library of Medicine, National Institutes of Health. (accessed March 7, 2016). (accessed March 7, 2016).


Christopher & Dana Reeve Foundation. 636 Morris Turnpike, Suite 3A, Short Hills, NJ 07078. Telephone: 973-379-2690. Website: (accessed March 7, 2016).

National Institute of Neurological Disorders and Stroke. PO Box 5801, Bethesda, MD 20824. Telephone: 301-496-5751. Website: (accessed March 7, 2016).

United Spinal Association. 120-34 Queens Blvd. #320, Kew Gardens, NY 11415. Toll-free: 800-404-2898. Telephone: 718-803-3782. Website: (accessed March 7, 2016).

* brain stem is the part of the brain that connects to the spinal cord. The brain stem controls the basic functions of life, such as breathing and blood pressure.

* central nervous system (SEN-trul NER-vus SIS-tem) is the part of the nervous system that includes the brain and spinal cord.

* fetus (FEE-tus) is the term for an unborn human after it is an embryo, from nine weeks after fertilization until childbirth.

* genetic (juh-NEH-tik) refers to heredity and the ways in which genes control the development and maintenance of organisms.

* computed tomography (komPYOO-ted toe-MAH-gruh-fee), or CT, is a technique in which a machine takes many x-rays of the body to create a three-dimensional picture. Formerly called computerized axial tomography (CAT).

* MRI, which is short for magnetic resonance imaging, produces computerized images of internal body tissues based on the magnetic properties of atoms within the body.

* vaccination (vak-sih-NAY-shun), also called immunization, is giving, usually by an injection, a preparation of killed or weakened germs, or a part of a germ or product it produces, to prevent or lessen the severity of the disease caused by that germ.

Disclaimer:   This information is not a tool for self-diagnosis or a substitute for professional care.

(MLA 8th Edition)