While most people don’t even think about breathing and how the human body does it, individuals that suffer from SMA don’t have that luxury.
The normal way the respiratory system functions is fairly simple: according to the SMA Foundation, the intercostal muscles (the ones that exist between the ribs) help the ribcage expand so when the lungs inflate they have space to do so. At the bottom of that ribcage, there’s the diaphragm which pulls the ribcage down so that there’s space for it to expand. For children with SMA, their respiratory system doesn’t work the same way which affects their physical appearance.
No one truly breathes from their stomach, but you will hear the term stomach breathing quite often if you have a child with SMA.
SMA attacks the muscles, so the muscles between the ribs that are needed to breathe don’t function as they should. However, the diaphragm works just fine. This means that while the chest wall won’t expand, the diaphragm will pull the ribcage down, which means that instead of the chest expanding, the stomach area will, giving it the illusion that the child is breathing from there, hence the term stomach breathing.
Due to mainly only using the diaphragm to breathe, the chest doesn’t expand which means the muscles in that area won’t strengthen at all. That being said, the ones lower down will. This usually causes the child to have what’s commonly called a “bell-shaped chest” which means the chest will be wider at the bottom than at the top. The fact that the diaphragm is always pulling the ribcage down will also cause a sunken chest. This is caused by the ribcage going down and the sternum, the bone in the middle of the chest, being pulled inwards.
It’s because of these differences in breathing behavior that respiratory care is so important for SMA. If you feel you need further information, talk to your medical team.
SMA News Today is strictly a news and information website about the disease. It does not provide medical advice, diagnosis or treatment. This content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or another qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this website.