What Is A Spinal Cord Injury / Disorder (SCI/D)?

What Is Spinal Cord Injury

Spinal cord injury (SCI) is an injury to the spinal cord that results in temporary or permanent changes in the spinal cord’s normal motor, sensory, or autonomic function. People who sustain a spinal cord injury often have permanent and profound neurologic deficits and accompanying disability.

Spinal cord injury can result in paralysis of the muscles used for breathing; paralysis and/or loss of feeling in all or some of the trunk, arms, and legs; weakness; numbness; loss of bowel and bladder control; and numerous secondary conditions including respiratory problems, pressure sores, and sometimes fatal spikes in blood pressure. For those who survive a spinal cord injury, the most important element of their care becomes preventing complications resulting from the injury, and the prevention of complications related to the disability.

There are approximately 17,000 new spinal cord injuries in the United States each year. Vehicle crashes are currently the leading cause of injury, followed by falls, acts of violence (primarily gunshot wounds), and sports/recreation activities.

Spinal column

The spinal cord is our largest nerve and the pathway for messages traveling between the brain and the rest of the body. The spinal column is divided into four sections, from which 31 pairs of nerves emerge and extend to the various parts of the body. The top portion of the spinal column is the cervical area, which has seven cervical vertebrae (identified as C-1 through C-7) from which eight pairs of cervical nerves emerge.

Next is the thoracic area, which includes the chest area and has twelve thoracic vertebrae (identified as T-1 through T-12), from which 12 pairs of thoracic nerves emerge. The lower back section is the lumbar area, with five lumbar vertebrae (L-1 through L-5) and five pairs of lumbar nerves; and the bottom section the sacral area has five vertebrae (S-1 through S-5) and five pairs of sacral nerves.

The bones in the sacral section, however, are actually fused together into one bone. At the very tip of the column, the coccyx, there is one pair of coccygeal nerves. In most spinal cord injuries, the backbones, ligaments, or disc material pinch the cord, causing it to become bruised or swollen. Sometimes the injury may tear the spinal cord and/or its nerve fibers. An infection or a disease can result in similar damage.

After a spinal cord injury, all the nerves above the level of injury keep working normally. At the level of injury, messages are blocked from being transmitted from above that level to below the level of injury. Depending on the level of injury, damage to the spinal cord can result in paralysis of the muscles used for breathing; paralysis and/or loss of feeling in all or some of the trunk, arms, and legs; weakness; numbness; loss of bowel and bladder control; and numerous secondary conditions including respiratory problems, pressure sores, and sometimes fatal spikes in blood pressure.

View The Level Of Injury Infograph

Spinal Nerves

There are 31 pairs of spinal nerves exiting the spinal column, with each spinal nerve having two roots, a front (anterior) motor root and a back (posterior) sensory root. The first spinal nerve however has no sensory root.

Motor Root

The front or anterior root carries signals from the spinal cord to muscles to initiate muscle movement.

Sensory Root

 The sensory root in the back carries information related to touch, position, pain, and temperature from the body to the spinal cord.

Tetraplegia or Quadriplegia

These terms generally describe the condition of a person with a spinal cord injury in the cervical region. This individual can experience a loss of feeling and/or movement in their head, neck, shoulder, arms and/or chest, stomach, hips, legs, and feet.


A general term describing the condition of a person who has lost feeling and/or is not able to move the lower parts of his/her body. The body parts that may be affected are the chest, stomach, hips, legs, and feet. Any thoracic level injury will cause paraplegia.

Incomplete Spinal Cord Injury

When an injury is incomplete, the spinal cord’s ability to carry messages to or from the brain is not completely lost. Often some sensation and movement remains below the level of injury.

Complete Spinal Cord Injury

In a complete spinal cord injury there is loss of sensation and motor function below the level of injury. Complete injuries are the most devastating and present with greater functional loss than an incomplete injury at a similar cord level.

Some Complications Resulting From A Spinal Cord Injury

The level of injury and the type of injury (incomplete or complete), usually will determine the extent of functional loss or disability that the individual will experience. Complications are numerous and often vary from individual to individual. Complications related to spinal cord injury will most often occur in multiples (bladder, bowel, skin, movement, etc.) further creating any number of resulting complications.

Upper Extremities
The loss of use of upper extremity function can vary greatly depending on the level of injury and type of injury (complete or incomplete). The higher the level of injury, the less upper extremity function there is. The lower level (paraplegic) injury may experience no deficits at all while the tetraplegic/quadriplegic injury may suffer complete loss of use. Not being able to use arms and/or hands can create great difficulties for someone with a spinal cord injury. It may mean hiring a care provider to help with activities of daily living such as cooking, bathing, dressing, grooming, shopping and taking medications. It also precludes the use of a manual wheelchair and creates dependency for mobility on another person (wheelchair pusher) or the use of a costly powered wheelchair that is difficult to transport and due to its mechanical nature, much more prone to breakdowns and expensive repairs.

Lower Extremities
As in all things spinal cord injury, the higher the level of injury, the less function that will be retained. Lower extremity functions such as walking, running, climbing, are almost always impaired or completely lost after injury at any cord level. A number of complications will arise that are related to not being able to stand and/or walk. Most SCI will experience atrophy (the loss of muscle bulk) as well as osteoporosis (decrease in bone density) which will place the individual at much higher risk for breaks and fractures. The inability to stand can also increase the risk of pressure sores to areas of the body such as buttocks, lower back and thighs since weight can not be relieved on these areas as a preventative measure. Acquisition of joint contractures, a condition where joints of the leg become rigidly locked in a certain position making it difficult at times to sit in a wheelchair properly, perform transfers to and from wheelchair, chairs, and cars, or get close to objects such as tables, doorknobs, and counters.

Loss of skin sensation below the level of injury. The individual may not feel and therefore not respond to prolonged pressure on the skin or damaging/painful levels of hot or cold. Without this protective mechanism an individual is more susceptible to pressure sores (damage to the skin and or underlying flesh), serious burns and issues related to exposure to cold.

Circulatory complications may range from low blood pressure to swelling of the extremities creating higher at risk situations for developing blood clots and pulmonary embolus. A life threatening circulation complication for SCI is rise in blood pressure known as autonomic dysreflexia or autonomic hyperreflexia.

The bladder stores urine as always. However, because of the the injury to the spinal cord, the individual may not be able to willfully void the bladder, control the flow of urine or even sense that they need to void. This loss of bladder control can increase the risk of urinary tract infections (UTI) and increase the risk of developing kidney infections and kidney stones. Use of an in-dwelling or external urinary catheter is often necessary to facilitate personal urinary care.

After an injury loss of control of bowel movements is often the case and it becomes difficult or impossible to empty one’s bowels. This condition is known as neurogenic bowel. It is a lack of nervous control (caused by a spinal cord injury or disease) that prevents the bowel from functioning correctly. The lack of function results in fecal incontinence, chronic constipation, or both. Bowel training (during rehab) can help regulate bowel movements but often a care provider is needed to complete the bowel maintenance process.

The higher level injuries, tetraplegia/quadriplegia can cause difficulties in breathing and coughing since the injury may have impacted on muscles (abdominal, diaphragm, chest muscles) that assist in breathing. At the higher levels of injury, impaired breathing may be so profound that the individual may need to be placed either temporarily or permanently on a respirator. This complication brings with it a greater risk of respiratory infection and pneumonia.

Sexual function and fertility can be affected after a spinal cord injury (SCI) in both men and women. Men may notice changes in erection and ejaculation; women may notice changes in lubrication and the ability to reach an orgasm. Very few men with complete SCI have ejaculations even though they may obtain an erection. Women however are able to get pregnant after a spinal cord injury. It is critical that individuals with a SCI contact urologists and fertility specialists who specialize in and are experienced with SCI.

What Is A Spinal Cord Disorder Or Disease?

Spinal cord disorders can cause permanent and irreparable cord problems. These disorders usually are a result of some condition outside of the spinal cord.

Multiple Sclerosis (MS)

Multiple sclerosis (MS) is a chronic, progressive, degenerative disorder that affects nerve fibers in the brain and spinal cord. Surrounding and insulating nerve fibers is a fatty substance known as myelin, which facilitates the conduction of nerve impulse transmissions. MS is characterized by intermittent damage to myelin in a process known as “demyelination” caused by the destruction of specialized cells oligodendrocytes that form myelin. Demyelination causes scarring and hardening (sclerosis) of nerve fibers, usually in the spinal cord, brain stem, and optic nerves, which slows nerve impulses and results in weakness, numbness, pain, and vision loss.

Amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig’s disease, is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles. The disease belongs to a group of disorders known as motor neuron diseases, which are characterized by the gradual degeneration and death of motor neurons. The cause of ALS is not known, and scientists do not yet know why ALS strikes some people and not others, but it occurs throughout the world with no racial, ethnic, or socioeconomic boundaries. ALS affects as many as 30,000 Americans, with 5,600 new cases diagnosed in the U.S. Each year.


Polio—also known as poliomyelitis—is a contagious viral disease that attacks the central nervous system and can cause temporary or permanent paralysis and weakness. While the disease has been virtually conquered in many areas of the world through vaccines, some survivors of childhood polio have been experiencing a new syndrome called “post-polio” that typically emerges 25 to 30 years after the initial attack.

Spina Bifida

Spina bifida is the most common neural tube defect. In the developing vertebrate nervous system, the neural tube is the precursor of the central nervous system. Neural tube defects result from the failure of the spine to close properly during the first month of pregnancy. Worldwide incidence of spina bifida is 1–2 cases per 1,000 births, but certain populations have a significantly greater risk

Transverse Myelitis

Transverse myelitis (TM) is a neurologic syndrome caused by inflammation of the spinal cord. TM occurs in both adults and children and is uncommon, but not rare. Conservative estimates of incidence per year vary from 1 to 5 per million population. The term myelitis is a nonspecific term for inflammation of the spinal cord; transverse refers to involvement across one level of the spinal cord. TM often develops in the setting of viral and bacterial infections, especially those which may be associated with a rash, such as rubella, influenza, or mumps. Approximately one third of patients with TM report flu-like symptoms prior to the onset of neurologic symptoms.


Syringomyelia (sear-IN-go-my-EEL-ya) is a disorder in which a cyst forms within the spinal cord. This cyst, called a syrinx, expands and elongates over time, destroying the center of the spinal cord. Since the spinal cord connects the brain to nerves in the extremities, this damage results in pain, weakness, and stiffness in the back, shoulders, arms, or legs. Other symptoms may include headaches and a loss of the ability to feel extremes of hot or cold, especially in the hands. Signs of the disorder tend to develop slowly. If not treated surgically, syringomyelia often leads to progressive weakness in the arms and legs, loss of hand sensation, and chronic, severe pain. In most cases, the disorder is related to a congenital abnormality of the brain called a Chiari I malformation.

Brown-Sequard Syndrome

Brown-Sequard syndrome (BSS) is a rare neurological condition that creates a lesion in the spinal cord. Contrary to conventional spinal cord injury that leaves most victims paralyzed on both sides of their body, Brown-Sequard syndrome results in weakness or paralysis (hemiparaplegia) on one side of the body and a loss of sensation (hemianesthesia) on the opposite side. Brown-Sequard may be caused by a spinal cord tumor, trauma or puncture wound ot the back or neck, obstruction of a blood vessels, infectious or inflammatory diseases such as tuberculosis, or multiple sclerosis.

Cauda Equina Syndrome

Cauda equina syndrome is a serious debilitating condition caused by compression of the nerves in the lower spinal canal. If left untreated Cauda Equina Syndrome can lead to permanent loss of bowel and bladder control as well as paralysis of the legs.