The phrenic nerve is among the most important nerves in the body due to its role in respiration. The phrenic nerve provides the primary motor supply to the diaphragm, the major respiratory muscle. It passes motor information to the diaphragm and receives sensory information from it.

What does the phrenic nerve do?

The phrenic nerve originates from the anterior rami of the C3 through C5 nerve roots and consists of motor, sensory, and sympathetic nerve fibers. It provides complete motor innervation to the diaphragm and sensation to the central tendon aspect of the diaphragm.

How does the phrenic nerve control breathing?

The phrenic nerve may not be something you have heard of before, but as you read this, it is keeping you alive. This nerve controls the diaphragm muscle, which controls the breathing process. When the diaphragm contracts, the chest cavity expands and creates room for inhaled air.