Phrenic Nerve

Question 1

what is the phrenic nerve and where does it originate and what does it two

Answer 1

bilateral, mixed nerve that originates in the neck and descends through the thorax to reach the diaphragm. As the only source of motor innervation to the diaphragm, this nerve has an important role in breathing.

Question 2

nerve roots of the phrenic nerve

Answer 2

Anterior rami of C3, C4 and C5.

Question 3

motor functions of phrenic nerve

Answer 3

Innervates the diaphragm.The phrenic nerve provides motor innervation to the diaphragm; the main muscle of respiration. As the phrenic nerve is a bilateral structure, each nerve supplies the ipsilateral side of the diaphragm (i.e. the hemi-diaphragm on the same side as itself).

Question 4

senonsory functions of phrenic nerve

Answer 4

Innervates the central part of the diaphragm, the pericardium and the mediastinal part of the parietal pleura.

Sensory fibres from the phrenic nerve supply the central part of the diaphragm, including the surrounding pleura and peritoneum. The nerve also supplies sensation to the mediastinal pleura and the pericardium.

Question 5

Anatomical Course of phrenic

Answer 5

The phrenic nerve mainly originates from the C4 spinal root, but it also receives contributions from C3 and C5. It also receives some communicating fibres from the cervical plexus.

The nerve begins at the lateral border of the anterior scalene muscle. It then continues inferiorly over the anterior surface of anterior scalene, deep to the prevertebral layer of deep cervical fascia. From here, the course of the phrenic nerve differs between the left and right:

Question 6

path of right phrenic

Answer 6

Right Phrenic Nerve:

Passes anteriorly to second part of the subclavian artery, and posteriorly to the subclavian vein.
Enters the thorax via the superior thoracic aperture.
Descends anteriorly to the right lung root, down the right side of the pericardium.
Reaches the diaphragm and pieces the muscle to supply the underlying surface.

Question 7

patth of left phenic

Answer 7

Left Phrenic Nerve:

Passes anteriorly to the first part of the subclavian artery, and posteriorly to the subclavian vein.
Enters the thorax via the superior thoracic aperture.
Crosses the aortic arch and vagus nerve, and descends anteriorly to the left lung root, down the left side of the pericardium.
Reaches the diaphragm and pieces the muscle to supply the underlying surface.
By TeachMeSeries Ltd (2018)