What is a Spinal Cord Injury?

A spinal cord injury is damage to any part of the spinal cord or nerves at the end of the spinal canal which often causes permanent changes in strength, sensation and other body functions below the site of the injury. A spinal cord injury typically begins with a sudden, traumatic blow to the spine that fractures or dislocates vertebrae. The damage to the spinal cord begins at the moment of injury when displaced bone fragments, disc material, or ligaments bruise or tear into spinal cord tissue. The spinal cord is a bundle of nerves that runs down the middle of the back. The spinal cord’s role is to carry signals back and forth between the body and brain. A spinal cord injury disrupts the signals.

Spinal cord injuries usually begin with a blow that fractures or dislocates vertebrae, the bone disks that make up the spine. Most injuries to the spinal cord don’t completely sever it, but rather such an injury is more likely to cause fractures and compression of the vertebrae, which then crush and destroy axons — extensions of nerve cells that carry signals up and down the spinal cord between the brain and the rest of the body. An injury to the spinal cord may damage a few, many, or almost all of these axons.

Spinal cord injuries can be complete or incomplete. With a complete spinal cord injury, the cord can’t send signals below the level of the injury. As a result, the individual becomes paralyzed below the injury. With an incomplete injury, individuals have some movement and sensation below the injury. A spinal cord injury is a medical emergency and immediate treatment has the potential to reduce long-term effects. Treatments may include medicines, braces or traction to stabilize the spine, and surgery. Additional treatment usually includes medicines and rehabilitation therapy. Mobility aids and assistive devices may help individuals in moving and completing daily tasks and/or living activities. Depending upon the manner and severity of injury some individuals will experience almost complete recovery while others injuries result in complete paralysis.

Any damage to the spinal cord is a very complex injury. People who are injured are often confused when trying to understand what it means to be a person with a spinal cord injury (SCI). Will I be able to move my hands? Will I walk again? What can I do? Each injury is different and can affect the body in many different ways. The following is a brief summary of the changes that take place after a spinal cord injury. It tells how the spinal cord works and what some of the realistic expectations are for what a person should eventually be able to do following a spinal cord injury.


The spinal cord is a part of the nervous system and the largest nerve in the body. Nerves are cord-like structures made up of many nerve fibers. The spinal cord has many spinal nerve fibers that carry messages between the brain and different parts of the body. The messages may tell a body part to move. Other nerve fibers send and receive messages of feeling or sensation back to the brain from the body, such as heat, cold, or pain. The body also has an autonomic nervous system. The spinal cord is responsible for the involuntary activities of the body; such as, blood pressure, body temperature, and sweating.

The nerve fibers that make up the communication systems of the body can be compared to a telephone system. The telephone cable (spinal cord) sends messages between the main office (the brain) and individual offices (parts of the body) over the telephone lines (nerve fibers). The spinal cord is the pathway that messages use to travel between the brain and the other parts of the body.

Because the spinal cord is such an important part of the nervous system, it is surrounded and protected by bones called vertebrae. The vertebrae, or backbones, are stacked on top of each other. This is called the vertebral column or the spinal column. The vertebral column is the number one support for the body. The spinal cord runs through the middle of the vertebrae.

The spinal cord is about 18 inches long. The cord extends from the base of the brain, down the middle of the back, to about the waist. The bundles of nerve fibers that make up the spinal cord itself are Upper Motor Neurons (UMNs). Spinal nerves that branch off the spinal cord up and down the neck and back are Lower Motor Neurons (LMNs). These nerves exit (figure C) between each vertebrae and go out to all parts of the body. At the end of the spinal cord, the lower spinal nerve fibers continue down through the spinal canal to the sacrum, or tailbone.

The spinal column is divided into four sections. The top portion is the cervical area. It has eight cervical nerves and seven cervical vertebrae. Moving down the back, the next section is the thoracic area. It includes the chest area and has twelve thoracic vertebrae. The lower back section is the lumbar area and has five lumbar vertebrae. The bottom section has five sacral vertebrae and is the sacral area. The bones in the sacral section are actually fused together into one bone.


Damage to the spinal cord can occur from either a traumatic injury or from a disease to the vertebral column. In most spinal cord injuries, the backbone pinches the spinal 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.

A spinal cord injury that is at a level from C1 to T1 often leads to the individual experiencing a loss of feeling and/or movement in the head, neck, shoulder, arms and/or upper chest. Paraplegia is the general term describing the condition of an individual 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.

An individual with a level from T2 to S5 has paraplegia. The higher the spinal cord injury is on the vertebral column, or the closer it is to the brain, the more effect it has on how the body moves and what one can feel. More movement, feeling and voluntary control of the body’s systems are present with a lower level of injury. For example, a person with a C-5 level of injury has a decreased or loss of feeling and movement below the 5th cervical spinal cord segment. An injury at the T-8 level means the individual has a decrease or loss of feeling and movement below the eighth thoracic spinal cord segment. Someone with a T-8 level of injury would have more feeling and movement than someone with a C-5 level of injury.


The amount of feeling and movement that an individual has also depends on whether the injury is complete or incomplete. A complete injury means there is no motor or sensory function in the S4 or S5 area, or anal area. If there is evidence of any motor or sensory function in this area, one of three incomplete injury classifications is given. Some people with an incomplete injury may have feeling, but little or no movement. Others may have movement and little or no feeling. Incomplete spinal injuries differ from one person to another because the amount of damage to each person’s nerve fibers is different. This fact makes it impossible to accurately predict how much of an individual’s sensory and motor function will return. There is a greater chance of return of some or all of a person’s motor and sensory function if an individual is incomplete at the time of injury.


Sometimes the spinal cord is only bruised or swollen after the initial injury. As the swelling goes down, the nerves may begin to work again. There are no tests at this time to tell how many nerves, if any, will begin to work again or when this will occur. This makes it impossible for medical staff to guarantee how much or when function may return.

Some individuals have involuntary movements, such as twitching or shaking. These movements are called spasms. Spasms are not a sign of recovery. A spam occurs when a wrong message from the nerve causes the muscle to move. The individual often cannot control this movement.

In addition to movement and feeling, a spinal cord injury affects how other systems of the body work. An individual with SCI learns new ways to manage his/her bladder and bowel. His/her skin and lungs often need special care and attention to stay healthy. There may also be changes in sexual function.


Functional goals are a realistic expectation of activities that an individual with SCI eventually should be able to do with a particular level of injury. These goals are set during rehabilitation with the medical team. They help the individual with SCI learn new ways to manage his/her daily activities and stay healthy. Achievement of functional goals can also be affected by other factors, such as an individual’s body type and health related issues. By striving to reach these functional goals, the hope is to give individuals with SCI the opportunity to achieve maximum independence.

Functional Goals for Specific Levels of Complete Injury


  • ABILITIES:  C3-limited movement of head and neck;
    • Breathing: Depends on a ventilator for breathing;
    •  Communication: Talking is sometimes difficult, very limited or impossible. If ability to talk is limited, communication can be accomplished independently with a mouth stick and assistive technologies like a computer for speech or typing; Effective verbal communication allows the individual with SCI to direct caregivers in the person’s daily activities, like bathing, dressing, personal hygiene, transferring as well as bladder and bowel management.
    • Daily tasks: Assistive technology allows for independence in tasks such as turning pages, using a telephone and operating lights and appliances.
    • Mobility: Can operate an electric wheelchair by using a head control, mouth stick, or chin control. A power tilt wheelchair is also useful for independent pressure relief


  • ABILITIES: Usually has head and neck control. Individuals at C4 level may shrug their shoulders;
    • Breathing: May initially require a ventilator for breathing, usually adjust to breathing full-time without ventilatory assistance.
    • Communication: Normal;
    • Daily tasks: With specialized equipment, some may have limited independence in feeding and independently operate an adjustable bed with an adapted controller.


  • ABILITIES: Typically has head and neck control, can shrug shoulders and has shoulder control. Can bend his/her elbows and turn palms face up.
    • Daily tasks: Independence with eating, drinking, face washing, brushing of teeth, face shaving and hair care after assistance in setting up specialized equipment.
    • Health care: Can manage their own health care by doing self-assist coughs and pressure reliefs by leaning forward or side-to-side.
    • Mobility: May have strength to push a manual wheelchair for short distances over smooth surfaces. A power wheelchair with hand controls is typically used for daily activities. Driving may be possible after being evaluated by a qualified professional to determine special equipment needs.


  • ABILITIES: Has movement in head, neck, shoulders, arms and wrists. Can shrug shoulders, bend elbows, turn palms up and down and extend wrists.
    • Daily tasks: With help of some specialized equipment, can perform with greater ease and independence, daily tasks of feeding, bathing, grooming, personal hygiene and dressing. May independently perform light housekeeping duties.
    • Health care: Can independently do pressure reliefs, skin checks and turn in bed.
    • Mobility: Some individuals can independently do transfers but often require a sliding board. Can use a manual wheelchair for daily activities but may use power wheelchair for greater ease of independence


  • ABILITIES: Has similar movement as an individual with C6, with added ability to straighten his/her elbows.
    • Daily tasks: Able to perform household duties. Need fewer adaptive aids in independent living.
    • Health care: Able to do wheelchair pushups for pressure reliefs.
    • Mobility: Daily use of manual wheelchair. Can transfer with greater ease.


  • ABILITIES: Has added strength and precision of fingers that result in limited or natural hand function.
    • Daily tasks: Can live independently without assistive devices in feeding, bathing, grooming, oral and facial hygiene, dressing, bladder management and bowel management.
    • Mobility: Uses manual wheelchair. Can transfer independently.


  • ABILITIES: Has normal motor function in head, neck, shoulders, arms, hands and fingers. Has increased use of rib and chest muscles, or trunk control.
    • Daily tasks: Should be totally independent with all activities.
    • Mobility: A few individuals are capable of limited walking with extensive bracing. This requires extremely high energy and puts stress on the upper body, offering no functional advantage. Can lead to damage of upper joints.


  • ABILITIES: Has added motor function from increased abdominal control.
    • Daily tasks: Able to perform unsupported seated activities.
    • Mobility: Same as above.
    • Health care: Has improved cough effectiveness.


  • ABILITIES: Has additional return of motor movement in the hips and knees.
    • Mobility: Walking can be a viable function, with the help of specialized leg and ankle braces. Lower levels walk with greater ease with the help of assistive devices.


  • ABILITIES: Depending on level of injury, there are various degrees of return of voluntary bladder, bowel and sexual functions.
    • Mobility: Increased ability to walk with fewer or no supportive devices.

Understanding the physiological effects of a spinal cord injury requires a basic knowledge of the anatomy and physiology of the spinal cord. Knowledge of the pathologic anatomy and physiology of a spinal cord injury (SCI) is also needed. Following this brief summary is a list of additional resources.


The spinal cord is the largest nerve in the body. Nerves are cord-like structures made up of nerve fibers. Nerve fibers are responsible for the communication systems of the body, which include sensory, motor, and autonomic functions. The nerve fibers within the spinal cord carry messages between the brain and the rest of the body.

Because the spinal cord is such an important part of the nervous system, protective bone segments, called the vertebral column, surround it. [See Figure A] The nerves that lie within the spinal cord are upper motor neurons (UMNs). They carry the messages back and forth from the brain to the spinal nerves along the spinal tract. The spinal nerves that branch out from the spinal cord to the other parts of the body are lower motor neurons (LMNs). These spinal nerves exit and enter at each vertebral level and communicate with specific areas of the body. The sensory portion of the LMNs carry messages to the brain about sensation from the skin and other body parts and organs. The motor portion of the LMNs send messages from the brain to the various body parts to initiate actions such as muscle movement. [See Figure B]

The vertebral column, or spinal column, is made up of 4 regions. Seven cervical vertebrae protect the eight cervical nerves; twelve thoracic vertebrae protect the twelve thoracic nerves; five lumbar vertebrae protect the five lumbar nerves; five sacral vertebrae, which are fused as one bone, help protect the five sacral nerves. [See Figure C]

As the body grows, the vertebral column grows more in length than the spinal cord, which usually ends between the first and second lumbar vertebrae. From this point the lumbar and sacral nerves branch out from the spinal cord and descend inside the spinal column before leaving the vertebral column at their corresponding vertebrae. Because of this fact there is often a discrepancy between the skeletal or bony level of vertebral fracture and the neurological level of spinal cord injury

Spinal Cord DiagramSpine Diagram


The term spinal cord injury (SCI) refers to any injury of the neural (pertaining to nerves) elements within the spinal canal. SCI can occur from either trauma or disease to the vertebral column or the spinal cord itself.

Most spinal cord injuries are the result of trauma to the vertebral column. Such trauma can cause a fracture of bone or tearing of ligaments with displacement of the bony column. This causes a pinching of the spinal cord. The vertebral trauma may cause contusion with hemorrhage and swelling of the spinal cord or it may cause a tearing of the spinal cord and/or its nerve roots. The damage from the spinal cord injury can affect the nerve fibers sending and receiving of messages from the brain to the body’s systems that control sensory, motor, and autonomic function below the level of injury.

It is important to distinguish between injuries that occur in the spinal cord proper from those that occur to the conus medullaris or to the cauda equina. [See Figure B] A spinal cord injury with preservation of segments of spinal cord below the level of injury usually produces an upper motor neuron (UMN) type of injury or spastic paralysis. The intrinsic reflexes are now uninhibited and become hyperreflexic and lead to increased muscle tone, spasms, and spasticity.  A conus medullaris injury, without preservation of spinal cord segments below the lesion, or a cauda equina injury produces a lower motor neuron (LMN) type of injury or flaccid paralysis. With this type of injury, the stimuli cannot reach the spinal cord; therefore, the reflexes and muscle tone remain decreased or absent (flaccid).


A complete evaluation of both sensory and motor levels will determine the neurological level of spinal cord injury. The recommended neurological assessment follows the classifications published in the “International Standards for Neurological and Functional Classification of Spinal Cord Injury”, revised 1996, endorsed by the American Spinal Injury Association and the International Medical Society of Paraplegia. Radiologic or anatomical abnormalities are not used in this classification system.


The neurologic level of injury is determined to be the most caudal (lowest) point on the spinal cord below which there is a decrease or absence of feeling (sensory level) and movement (motor level) on both sides of the body. The physician tests 10 paired groups of index muscles [myotomes] to determine the motor level of the patient. A motor score between 0 – 5 is given based on motor function. A “3” is given for active, full range of movement against gravity. This is the minimal score needed to set functional goals with a specific level of injury.The 28 key sensory points [dermatomes – the nerve roots that receive sensory information from the skin areas] are also examined for sensitivity to pin prick and light touch. This determines the sensory level.

The sensory and motor levels need to be evaluated for both the right and left sides of the body. It is not unusual to have a discrepancy between the lowest normal motor level and the lowest normal sensory level.

Another general classification used to refer to a spinal cord injury is the terms tetraplegia or paraplegia. Tetraplegia [formerly called quadriplegia] generally describes the condition of a person classified with a spinal cord injury between C1 and T1. These individuals experience a loss of feeling and/or movement in their head, neck, shoulder, upper chest, arms, hands, and/or fingers. Paraplegia is the term that describes the condition of a person who has been classified with an injury between levels T2 and S5. The body’s motor and/ or sensory function(s) affected with paraplegia can include the middle of the chest, the stomach, hips, legs and feet, and/or toes.


A complete injury means that there is no motor or sensory function preserved in the S4 and S5 area, or anal area. A rectal exam determines if there is rectal sensation and voluntary sphincteric contraction. If there is evidence of any motor or sensory function in this area, one of three incomplete injury classifications is given according to the ASIA Impairment Scale.


Spinal cord injury occurs with an incidence of approximately 40 cases per million population in the U.S. or approximately 10,000 new cases each year.

Spinal cord injury is primarily an injury of young men. The ratio of males to females is approximately 4 to 1 with 82% males and 18% females. The greatest number of injuries occur between the ages of 16 and 30 (55%). The mean age at time of injury has increased from 28.6 in 1979 to 35.1 in 1990. Since 1990, motor vehicle crashes account for 37.4% of the SCI cases reported. The next largest contributor is acts of violence (25.9%), primarily gunshot wounds. The third most common cause is falls at 21.5%, with sports injuries ranking fourth at 7.1%.

Spinal cord injury can occur at any level of the spinal column or at multiple levels. The most common area of injury is the lower part of the neck at the C-4, C-5, and C-6 levels. The second most common area is between T-12 and L-1, which is at the bottom of the rib cage. Since 1990 the most frequent neurologic category is incomplete tetraplegia (29.5%), followed by complete paraplegia (27.9%), incomplete paraplegia (21.3%), and complete tetraplegia (18.5%). Individuals with a spinal cord injury designated as having tetraplegia are slightly more common than paraplegia, 51.7% and 46.7%, respectively.


The most common causes of spinal cord injuries in the United States are:

  • Motor vehicle accidents. Auto and motorcycle accidents are the leading cause of spinal cord injuries, accounting for more than 40 percent of new spinal cord injuries each year.
  • Falls. Spinal cord injury after age 65 is most often caused by a fall. Overall, falls cause more than one-quarter of spinal cord injuries.
  • Acts of violence. As many as 15 percent of spinal cord injuries result from violent encounters, often involving gunshot and knife wounds, according to the National Institute of Neurological Disorders and Stroke.
  • Sports and recreation injuries. Athletic activities, such as impact sports and diving in shallow water, cause about 8 percent of spinal cord injuries.
  • Alcohol. Alcohol use is a factor in about 1 out of every 4 spinal cord injuries.
  • Diseases. Cancer, arthritis, osteoporosis and inflammation of the spinal cord also can cause spinal cord injuries.
  • To view statistical data regarding incidences of SCI from a study by the National Spinal Cord Injury Statistical Center click here: https://www.nscisc.uab.edu/PublicDocuments/nscisc_home/pdf/Facts%202011%20Feb%20Final.pdf


Many scientists are optimistic that advances in research will someday make the repair of spinal cord injuries possible. Research studies are ongoing around the world. In the meantime, treatments and rehabilitation allow many people with a spinal cord injury to lead productive, independent lives.


Anytime individual experiences significant trauma to his or her head or neck the individual needs immediate medical evaluation for the possibility of a spinal injury. In fact, it’s safest to assume that trauma victims have a spinal injury until proven otherwise because:

  • A serious spinal injury isn’t always immediately obvious. If it isn’t recognized, a more severe injury may occur.
  • Numbness or paralysis may result immediately or come on gradually as bleeding or swelling occurs in or around the spinal cord.
  • The time between injury and treatment can be critical in determining the extent of complications and the amount of recovery.
  • Don’t move the injured person — permanent paralysis and other serious complications may result.
  • Call 911 or your local emergency medical assistance number.
  • Keep the person still.
  • Place heavy towels on both sides of the neck or hold the head and neck to prevent them from moving, until emergency care arrives.
  • Provide basic first aid, such as stopping any bleeding and making the person comfortable, without moving the head or neck.



Diagnosing a spinal cord injury begins during emergency treatment and usually requires subsequent neurological exams. X-rays, CT scans, and/or MRIs may be administered to determine the individual’s level and completeness of the injury. The level of injury refers to the location along the spinal cord where the injury occurred and indicates which parts of the body may be affected. The completeness of the injury refers to the extent of damage to the spinal cord and indicates the degree of paralysis (full or partial) in the body parts that were affected.

During diagnosis, the individual’s movement and muscle strength will be tested along with their response to light-touch and pinpricks to various parts of the body. Physicians may use one or more of the following scales to rate an injured person’s responses to the tests.

  • American Spinal Injury Association Scale (ASIA)
  • Neurological Level of Injury (NLOI)
  • Function Independence Measure (FIM)
  • Quadriplegic Index of Function (QIF)
  • Modified Barthel Index
  • Spinal Cord Independence Measure (SCIM)
  • Capabilities of Upper Extremity Instrument (CUE)
  • Walking Index for SCI (WISCI)
  • Canadian Occupational Performance Measure (COPM)

In the emergency room, a doctor may be able to rule out a spinal cord injury by careful inspection, testing for sensory function and movement, and asking some questions about the accident. But if the injured person complains of neck pain, isn’t fully awake, or has obvious signs of weakness or neurological injury, emergency diagnostic tests may be needed.

These tests may include:

  • X-rays. Medical personnel typically order these tests on people who are suspected of having a spinal cord injury after trauma. X-rays can reveal vertebral (spinal column) problems, tumors, fractures or degenerative changes in the spine.
  • Computerized tomography (CT) scan. A CT scan may provide a better look at abnormalities seen on an X-ray. This scan uses computers to form a series of cross-sectional images that can define bone, disk and other problems.
  • Magnetic resonance imaging (MRI). MRI uses a strong magnetic field and radio waves to produce computer-generated images. This test is very helpful for looking at the spinal cord and identifying herniated disks, blood clots or other masses that may be compressing the spinal cord.

Once some of the swelling has subsided after the initial injury, the doctor will conduct a neurological exam to determine the level and completeness of the individual’s injury. This involves testing muscle strength and the ability to sense light touch and a pinprick


The first step in diagnosing a spinal cord injury is a medical history and physical examination. The individual’s physician will obtain a medical history asking questions about the details surrounding the time of the injury. The amount of time since the injury is important because spinal cord injury is a medical emergency. The quicker the individual seeks medical treatment, the better the chances for recovery. Other details of the medical history which should be relayed to the treating doctor include details of any prior neck or back injuries or surgeries, the presence of pain in the neck or back, any weakness in the arms or legs, loss of bowel or bladder control, loss of sensation in the arms or legs, and other previous medical conditions.

The physical examination will include testing to see if sensation to touch is intact in the arms and legs as well as testing muscle strength and reflexes in the arms and legs. The individual may be kept in a cervical collar or on a backboard to immobilize them until the physician determines whether or not the patient has a spinal cord injury.

The next step is often x-rays of the neck or back. These can help identify a fracture or dislocation of the vertebrae. These may or may not be present with a spinal cord injury. It is possible to have a spinal cord injury without an injury to the vertebrae. X-rays can also help identify a tumor, infection or severe arthritis that could cause spinal cord injury.

A computed tomography (CT) scan is a more advanced imaging test that can give the physician a better view of the vertebrae. A CT scan can identify some injuries to the vertebrae not seen on the plain x-rays. A magnetic resonance imaging (MRI) scan is another more advanced imaging study that can identify a spinal cord injury. The MRI is better at evaluating the soft tissues including the ligaments, intervertebral discs, nerves and spinal cord. The MRI scan also can show evidence of injury within the spinal cord.

Today, advances in stem cell research and nerve cell regeneration give hope for a greater recovery for people with spinal cord injuries. At the same time, new medications are being investigated for people with long-standing spinal cord injuries. No one knows when new treatments will be available, but you can remain hopeful about the future of spinal cord research while living your life to the fullest today.