Diaphragm
Respiratory
If your diaphragm stopped working, you'd stop breathing. It contracts about 20,000 times a day. 'C3, 4, 5 keeps the diaphragm alive.'
Function
Primary muscle of inspiration — flattens to draw air into lungs
Origin
Xiphoid process, costal cartilages 7-12, L1-L3 vertebrae, arcuate ligaments
Insertion
Central tendon
Innervation
Phrenic nerve (C3-C5)