Injury at C3 would completely impair breathing, with partial impairment down to C5. The accessory muscles that assist with breathing (not the diaphragm) like the intercostals can be affected all the way down to T12 with varying degrees of impairment.
Source: orthopedic resident who sometimes does spine surgery
_irish_potato t1_jdb53xc wrote
Reply to (Biology) How far down your spine can you break before respiratory impairment? by Anomaly-Friend
Injury at C3 would completely impair breathing, with partial impairment down to C5. The accessory muscles that assist with breathing (not the diaphragm) like the intercostals can be affected all the way down to T12 with varying degrees of impairment.
Source: orthopedic resident who sometimes does spine surgery