diaphram

[mneary]

Can you tell me at what level the diaphram is affected by an SCI? I'm T5/T6 complete and was just wondering if my diaphram was partially paralyzed, because I'm unable to sneeze like I used to. Or is it because I don't have any ab muscles?

[SCI-Nurse]

There are 4 groups of respiratory muscles:

Diaphragm (which is the main breathing muscle):
Innervated at C3-5 ("3,4,and 5 keep the diaphragm alive"). The most important branch is C4. Most people at C4 can therefore be completely ventilator free, while few can be if complete C3.

Accessory muscles:
These are the sternocleidomastiod (C5-8) and scalene (C2-3) muscles in the neck which attach to the upper rib cage. They are important for taking an extra deep breath.

Intercostal muscles:
These are the muscles between the ribs that are responsible for elevating the rib cage (external intercostals) and also provides some force to coughing and other forced expiration (like sneezing) through the internal intercostals. Both are innervated between T1-7. The intercostals do about 30% of the work of breathing.

Abdominals:
The abdominals stabilize the diaphragm and make it more efficient, but mostly they are responsible for any type of forced expiration (breathing out hard, blowing up a balloon, sneezing, and most importantly, coughing). They are innervated at T6-12. If they are paralyzed, when the diaphragm descends into the abdominal area during inspiration, the abdomen pushes out from the increased intra-abdominal pressure. This is sometimes called paradoxical respiration or sometimes (inaccurately) abdominal breathing.

If the abdominals are paralyzed, the cough, sneeze, etc. will be weak. This can be aided by the use of "quad coughing" to make both more effective. If you have good hand function you may be able to do this yourself.

(KLD)