There are two major muscles involved in breathing:
- the diaphragm, supplied by the spinal nerves C3-C5
- the intercostal muscles (muscles between the ribs), supplied by thoracic spinal nerves T1-T12
The other muscles important in your respiratory function are the abdominal muscles, which are supplied from the thoracic spinal nerves from T6-T12, as these are used in coughing.
What does this mean for my injury level?
- C3 or above: you will most likely require a ventilator or diaphragm pacing device to assist with breathing.
- C4: you may be able to breathe independently all day and perhaps require mask ventilation at night.
- C5 or below: you will generally be able to breath on your own without assistance but your lung volume will be reduced by about half of your pre-injury level.
- Thoracic spine: you will have some weakness of the respiratory muscles, the lower you are the less weakness you will have
- Lumbar region: minimal weakness or no change at all
After a spinal cord injury your lung volume will be reduced. The higher your injury, the more your lung volume will be reduced compared with your pre-injury level. This will mean that you are more likely to feel breathless when exercising. Working on your fitness with your physiotherapist and other team members will help to improve your lung volume over time and eventually your lung volume will increase to be up to 70-80% of your previous level. The exercise which is most useful for improving your lung volume is aerobic activity.
Examples of aerobic exercise:
Anything which raises your heart rate and gets you breathing deeply like:
- Pushing a manual wheelchair
- Playing rugby
- Arm cycling
- Or even singing
Increasing the strength of the muscles around your shoulders can also improve your ability to breathe deeply as some of these can help you to take deep breaths and cough more strongly. Specific breathing exercises with equipment such as resistive inhalers has been shown to increase respiratory muscle strength during the time you engage in the training program, but the effects do not seem to be sustained if you stop doing the training. Engaging in an activity which fits your lifestyle like a sport or regular singing can be easier to maintain and reap the benefits from in the longer term.