You & Your Spinal Cord - Patient Education Series
The material in this section is presented to patients in Toronto Rehab’s Spinal Cord Rehabilitation Program as part of the Patient Education Series. Topics covered include:
- The spine
- The nervous system
- The spinal cord
- Level of injury
- Types of injury
- Spinal cord organization
- Complete/incomplete injuries
- How spinal cord injury (SCI) affects my body:
- Spasms
- Clonus
- Associated reactions
- Autonomic dysreflexia
- Orthostatic hypotension
The spine
Bones provide
protection. They protect the soft brain and spinal cord while muscles provide support.
Your back is made up of 33 bones called vertebrae, 31 pairs of nerves, 40 muscles and many connecting tendons and ligaments that run from the base of your skull to your tailbone.
Between your vertebrae are fibrous, elastic cartilage called discs. They act like shock absorbers—keeping your spine flexible and they cushion the hard vertebrae as you move about.
What’s holding it together?
Ligaments provide stability but allow flexibility. But they can tear with high forces.
If any structure is injured along the spine and neck, the spinal cord can be damaged.
- Disks act like cement to hold everything together and they also act like cushions to absorb impact.
The vertebral column
Sections of the spine include:
- Cervical
- Thoracic
- Lumbar
- Sacral
How many bones in each section?
- C-spine = 7
- T-spine = 12
- L-spine = 5
- S-spine = 1 (5 fused together)
- Coccyx = 1 (4 fused together)
Every bone in the T-section of the spine is attached to a rib. This makes the mid-back more rigid.
The spinal cord
Divided into sections the same way the bones are.
Nerves of the C-spine serve:
- the head
- the neck
- the diaphragm
- arms and hands
Nerves of the T-spine serve:
Nerves of the L-spine serve:
Nerves of the Sacrum serve:
- bowel
- bladder
- sexual function
Nerve cell
Also known as a neuron, a nerve cell is a cell that conducts neural electric impulses from one part of the body to another—it is the powerhouse of the nerve.
Neurons are made up of dendrites (branch-like fibers that receive impulses/signals) and axions (fibers which send impulses/signals). They communicate with other neurons and organs at junctures called synapses.
Cross section of spinal cord
This illustration shows the complexity of the spinal cord. The sections in red show the message pathways that come from the brain to the rest of the body.
The blue sections show which part of the cord sends messages, such as sensation and pain, back to the brain.
The red and blue are combined on each side of the cord. This illustration has separated them to more easily show the message pathways.
Types of injuries: Traumatic
Traumatic injuries usually occur as a result of falls and car crashes.
- Spinal cord injury without bony injury
- Dislocation
- Bony fracture without SCI
- Compression fractures
- Burst fractures
Types of injuries: Non-traumatic
Non-traumatic injuries are caused by:
- Degenerative changes
- Tumours
- Infections
Examples include arthritis or West Nile Virus.
Complete vs. incomplete injuries
Complete injuries occur when signals from the brain and body are not able to get beyond the level of the injury—going up or down.
Incomplete injuries involve mixed signals up and down the spinal cord.
Cauda equine – The spinal cord ends between L1 and L2, with nerve roots extended below into the sacrum. An injury above L1 is an injury to the spinal cord proper but an injury below happens to the roots.
Autonomic nervous system
The autonomic nervous system is everything you don’t have to concentrate on in order for it to work. For example: breathing, digestion and heart beat.
The parasympathetic system controls everything in your body to do with rest and digest. The sympathetic system is your fight or flight responses.
Autonomic dysreflexia
Symptoms include:
- pounding headache
- red skin and sweating above the level of the injury
- nausea, irritability
Also known as hyperreflexia, it is a condition where the blood pressure becomes excessively high in a person with a spinal cord injury above T5-6. It is due to over-activity of the autonomic nervous system.
Usually happens when something painful occurs below the level of the spinal cord injury. Anything that would have been painful, uncomfortable or physically irritating before the injury may cause autonomic dysreflexia after the injury.
The most common cause seems to be overfilling of the bladder, which could be due to a blockage in the urinary drainage device, bladder infection (cystitis), inadequate bladder emptying, bladder spasms or possibly stones in the bladder.
The second most common cause is a bowel that is full of stool or gas. Any stimulus to the rectum such as digital stimulation, can trigger a reaction, leading to autonomic dysreflexia.
Other causes include:
- skin irritations
- wounds
- pressure sores
- burns
- broken bones
- pregnancy
- ingrown toenails
- appendicitis
- ther conditions and medical complications from a blocked catheter and tight or restrictive clothing to sexual activity and skeletal fractures
Causes of autonomic dysreflexia must be addressed in order for the person to be relieved of symptoms.
Orthostatic hypotension
A sudden fall in blood pressure that occurs when a person moves into an upright position.
It can be caused by hypovolemia (a decreased amount of blood in the body), resulting from the excessive use of diuretics, vasodilators or other types of drugs, dehydration or prolonged bed rest.
It may be associated with Addison’s disease, atherosclerosis (build-up of fatty deposits in the arteries), diabetes and certain neurological disorders including Shy-Drager syndrome and other dysautonomias.
Symptoms—which often occur when a person moves from lying to sitting or sitting to standing—include dizziness, lightheadedness, blurred vision and syncope (temporary loss of consciousness).
Body temperature
People with spinal cord injury can experience hypothermia or hyperthermia. If you don’t have sensation in parts of your body, be sure to dress appropriately. Stay warm in the winter with multiple layers. In the summer, wear light clothes and stay in the shade.
You may be unable to shiver when cold or sweat when hot. Sometimes people help themselves sweat by spraying water on their limbs to keep cool.
Spasticity
This is any unregulated movement of the body’s muscles. The brain is unable to shut off muscle activity below the level of injury, resulting in spasms.
Receptors in muscles that are responsive to changes in length and tension
- Sensitivity of these receptors is regulated by the central nervous system
- Can become overly responsive to stimulus that normally your body would ignore
Associated reactions
- These include abnormal reflexes or involuntary movements that can occur in response to movement of another part of the body. For example: a person with quadriplegia will experience involuntary bending of the elbows in response to yawning.
Clonus
- This is the rhythmic, involuntary contraction of a muscle in response to the stretching of that muscle. It happens most commonly in the ankles, when stretching the calf will cause the foot to bounce up and down.
Pros and cons of spasticity
Pros
- Prevention of denervation atrophy. This is the shrinking of muscle tissue that happens due to a decrease in nerve connection to that muscle. By having spasms, the nerve causes the muscle to contract, and this preserves some of the connections and prevents the muscle from shrinking away to the extent that it would otherwise.
- Can be useful for functional activities (Pay attention to your spasms in order to learn what might trigger them and how you can use them to your advantage—in transfers for example, as well as what you can do to reduce spasms, such as daily stretching).
- Spasms can be an indicator of other problems such as kidney stones or urinary tract infection.
Cons
- Decrease range of motion
- Joint changes
- Contractures that lower your independence in functional activities
Managing spasticity
- Physiotherapy management through weight-bearing and stretching exercises
- Pharmacological management through use of medications including Baclofen and Diazepam
Chronic pain
- Many people with spinal cord injuries experience pain.
- Various methods are used to try and manage pain:
- Exercise
- Medication
- Acupuncture
- Meditation/relaxation