Motor innervation of rodent diaphragm.

In order to investigate the possibility of an intercostal nerve contribution to the motor innervation of the diaphragm, the phrenic nerve was interrupted unilaterally in the root of the neck in rats and mice and the pattern of innervation was later studied histologically. The results showed the phrenic nerve to be the sole source of motor innervation. The only contribution from intercostal nerves was to blood vessels and to intramuscular connective tissue.