Vagus vs Phrenic Nerve: Key Differences and Anatomy Quiz

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Questions and Answers

What is the origin of the vagus nerve?

From the spinal cord

From the medulla oblongata of the brain stem (correct)

From the subclavian artery

From the thoracic inlet

What is the name 'vagus' derived from?

Latin word for 'mixed nerve'

Latin word for 'wandering' or 'vague' (correct)

French word for 'phrenic nerve'

Greek word for 'brain stem'

Which part of the subclavian artery does the vagus nerve cross in front of?

First part (correct)

Third part

All parts

Second part

What type of fibers does the vagus nerve contain?

Motor, sensory, and parasympathetic fibers Signup and view all the answers

What is the function of the parasympathetic fibers in the vagus nerve?

To slow down the heart and smooth muscles Signup and view all the answers

What is the accessory phrenic nerve derived from?

C5 Signup and view all the answers

What is the primary destination of the vagus nerves after descending through the oesophageal opening of the diaphragm?

Abdomen Signup and view all the answers

Which vagus nerve forms the posterior gastric nerve?

Right vagus Signup and view all the answers

What type of fibres do the branches of the vagus nerve provide to the corresponding plexuses?

Parasympathetic Signup and view all the answers

What is the origin of the 2 vagi?

Lower ends of the oesophageal plexuses Signup and view all the answers

Which of the following is NOT a branch of the vagus nerve in the thorax?

Phrenic Signup and view all the answers

Where does the right vagus nerve meet the king Bila vagus nerve?

At the root of the lung Signup and view all the answers

What is the function of the posterior pulmonary plexus?

Formation of the posterior oesophageal plexus Signup and view all the answers

How many branches descend to the oesophagus to share in the formation of the posterior oesophageal plexus?

123 Signup and view all the answers

Where does the left vagus nerve share in the formation of the posterior oesophageal plexus?

On the back of the oesophagus Signup and view all the answers

What is the location of the posterior mediastinum?

Behind the root of the lung Signup and view all the answers

Where does the left recurrent laryngeal nerve arise from?

The left vagus nerve Signup and view all the answers

What is the path of the left recurrent laryngeal nerve in the thorax?

It hooks below the arch of the aorta Signup and view all the answers

Where does the left recurrent laryngeal nerve ascend?

Deep to the arch of the aorta Signup and view all the answers

What is the clinical importance of the vagus nerve in the thorax?

It can be compressed by an aortic aneurysm or enlarged lymph nodes Signup and view all the answers

What is the location of the thoracic part of the sympathetic chain?

Along the vertebral column Signup and view all the answers

What is the function of the cardiac branches of the left recurrent laryngeal nerve?

Forming the deep cardiac plexus Signup and view all the answers

Study Notes

Phrenic Nerve

The phrenic nerve is composed of fibres from C3, 4, and 5, with the fibres from C5 constituting a separate nerve called the accessory phrenic nerve.
In most cases, the accessory phrenic nerve joins the main part of the phrenic nerve at the level of the 1st rib.
If the accessory phrenic nerve is present, surgical cutting of the main phrenic nerve will not achieve complete paralysis of the corresponding part of the diaphragm.

Vagus Nerve

The vagus nerve is the 10th cranial nerve, arising from the medulla oblongata of the brain stem.
It is a mixed nerve, containing motor, sensory, and parasympathetic fibres.
It enters the thorax through the thoracic inlet, crossing in front of the 1st part of the subclavian artery.
The right vagus gives its recurrent laryngeal branch in the thorax.
The vagus nerve runs its course first in the superior and then in the posterior mediastinum.
The 2 vagi are formed again from the lower ends of the oesophageal plexuses and descend through the oesophageal opening of the diaphragm to enter the abdomen as the gastric nerves.
The right vagus forms the posterior gastric nerve, while the left vagus forms the anterior gastric nerve.
Branches of the vagus nerve in the thorax include cardiac, pulmonary, and oesophageal branches, as well as the left recurrent laryngeal nerve.
These branches provide parasympathetic fibres to the corresponding plexuses.

Left Recurrent Laryngeal Nerve

The left recurrent laryngeal nerve arises from the left vagus nerve as it lies on the left anterior aspect of the arch of the aorta.
It hooks below the arch of the aorta, behind and to the left of the ligamentum arteriosum.
It ascends deep to the arch of the aorta, in the left side of the groove between the trachea and the oesophagus.
It leaves the superior mediastinum to enter the root of the neck by passing through the inlet of the thorax.
Branches in the thorax include cardiac branches to the deep cardiac plexus, and tracheal and oesophageal branches.
Compression of the vagus nerve by an aortic aneurysm or enlarged tracheobronchial lymph nodes can lead to hoarseness of voice or persistent cough.

Thoracic Part of the Sympathetic Chain

The sympathetic chain is a trunk of nerve fibres and ganglia that runs along the vertebral column, one on each side.
The thoracic part of the sympathetic chain gives off branches which form the posterior pulmonary plexus.
The right vagus shares in the formation of the posterior oesophageal plexus on the back of the oesophagus.
The left vagus shares in the formation of the anterior oesophageal plexus.

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Description

This quiz covers the anatomy of the phrenic and vagus nerves, including their origins, composition, and functions. It also explores the relationship between these nerves and the diaphragm. Test your knowledge of these important nerves!