Phrenic Nerve

NEURAL PATHWAY

The phrenic nerve arises from the C3-C5 spinal roots (mainly C4). it descends through the neck and thorax to innervate the ipsilateral hemidiaphragm.

Branches of C3,C4, and C5 → Phrenic Nerve

Anatomical location and path of the phrenic nerve (source)
Anatomical location and path of the phrenic nerve (source)
FUNCTION

This nerve controls the activity of the ipsilateral hemidiaphragm.

CAUSE OF INJURY

Compression/irritation of this nerve can be caused by various mechanisms:

  • Mass effect due to malignancy
CLINICAL PRESNENTATION

Diaphragmatic irritation can manifest as dyspnea amor hiccups

Shoulder pain: this nerve will refer pain to the shoulder on the affected side. This is because the area innervated by the supraclavicular nerve originates from C3, C4.

Respiratory distress can be a consequence of phrenic nerve palsy. Decreased breath sounds can be present, and an elevated hemidiaphragm can be noticed on a chest X-ray.

This X-ray shows an elevated right hemidiaphragm that is caused by phrenic nerve palsy (source)
This X-ray shows an elevated right hemidiaphragm that is caused by phrenic nerve palsy (source)

 

Page Updated:08.09.2016