Nucleus of the Phrenic Nerve [N. Nervi Phrenici (N. Phrenicus), Pna]

Nucleus of the phrenic nerve [n. nervi phrenici (n. phrenicus), pna] - nucleus located in the anterior columns of the spinal cord at the level of III – V cervical segments. It gives rise to motor fibers of the phrenic nerve. The phrenic nerve innervates the diaphragm, the main respiratory muscle that separates the chest cavity from the abdominal cavity. The phrenic nerve nucleus is activated during inspiration, sending impulses along the motor fibers of the nerve to the diaphragm, causing it to contract and the dome of the diaphragm to relax. This leads to an increase in chest volume and air flow into the lungs. Thus, the nucleus of the phrenic nerve plays an important role in ensuring the breathing process, being the main center of innervation of the diaphragm. Damage to this nucleus leads to paralysis of the diaphragm and serious breathing problems.

The phrenic nerve fiber nucleus, which is also called the Phrenic Nerve Fiber Nucleus (PNA) or Nucleus n. The phrenics (English: t.) is a pinkish-red oval nucleus in the anterior part of the posterior white commissure of the spinal cord, at the level of the third, fourth and fifth cervical segments. This is one of two centers originating in the lateral horns of the gray matter