Neurovascular Structures in the Neck 2 Flashcards
What structures does the vagus follow the course of?
It follows the course of the internal and external carotid arteries and the internal jugular vein – therefore it contributes to a great neurovascular bundles with these vessels.
What is the great neurovascular bundle with the vagus nerve called and what is it surrounded by?
This is called the carotid sinus and it is loosely bound by connective tissue.
How does the vagus nerve enter the thorax?
It runs down the carotid sheath and eventually over the front of the subclavian artery to enter the thorax.
What does the vagus nerve give off after leaving the skull?
It gives off a pharyngeal branch.
What do the fibres of the pharyngeal branch of the vagus nerve form on the surface of the pharyngeal muscle?
They form a meshwork on the surface of the pharyngeal muscles and they carry motor fibres to the pharynx and the palate.
What is the uppermost branch of the vagus nerve to the larynx?
The superior laryngeal nerve.
What does the superior laryngeal nerve divide into?
Divides to give a sensory branch and a motor branch.
What is the sensory branch of the superior laryngeal nerve?
This is the internal laryngeal nerve.
How does the internal laryngeal nerve enter the larynx?
It enters the larynx by piercing a membrane.
What is the motor branch of the superior laryngeal nerve called?
It is called the external laryngeal nerve.
What is the external laryngeal nerve destined to supply?
It is destined to supply one important muscles on the surface of the larynx.
What artery does the superior laryngeal nerve follow to form a neurovascular bundle?
It follows the superior thyroid artery to form a neurovascular bundle.
What is the lower branch of the vagus nerve to the larynx on the right?
This is the right recurrent laryngeal nerve.
How does the right recurrent laryngeal nerve form a neurovascular bundle?
It hooks around the right subclavian artery and ascends with the inferior thyroid artery to form another important neurovascular bundle.
What does the right recurrent laryngeal nerve supply?
It enters the larynx to supply the remainder of the laryngeal muscles.
Where does the left recurrent laryngeal nerve arise?
It arises in the thorax.
What does the left recurrent laryngeal nerve do before it ascends into the neck?
It hooks around the arch of the aorta before ascending into the neck.
What is the relationship of the left recurrent laryngeal nerve with the inferior thyroid artery?
It ascends with the inferior thyroid artery to form another neurovascular bundle.
How does the 11th cranial nerve = the accessory nerve arise?
The cranial root - arise from the brain just below the vagus
The spinal root - arise from the upper part of the spinal cord
When do the 2 roots of the accessory nerve converge?
They join and converge on the vagus nerve just before the 10th and 11th cranial nerves leave the skull.
What happens to the accessory nerve after it leaves the jugular foramen?
They separate again.
What do the cranial fibres of the accessory nerve join after pass through the jugular foramen?
They join the vagus nerve.
What happens to the spinal fibres of the accessory nerve?
They travel on as a separate nerve.
What is the vagus nerve entering the neck a mixture of?
It is actually a mixture of vagoaccessory fibres.
More accurately, what is the accessory nerve in neck?
This is more accurately the spinal part of the accessory nerve.
How does the vagoaccessory mixture supply motor fibres to the muscles of the pharynx?
They supply the muscles of the pharynx through the pharyngeal branch of the vagus.
What is the pharyngeal plexus made of?
- motor pharyngeal complex of vagoaccessory mixture
- sensory fibres from the glossopharyngeal nerve
- a few sympathetic fibre
these form a meshwork of nerve fibres on the pharyngeal wall
What does the pharyngeal plexus supply?
It supplies motor and sensory nerve fibres to the pharynx.
Motor supply to the muscles of the soft palate except the tensor palati.
What do the laryngeal nerves contain a mixture of?
They contain a mixture of true vagal and cranial accessory fibres.
In terms of the vagal fibres, what do we seen in the thorax and the abdomen?
By the time the vagal trunks have reached the thorax, on their way to the abdomen, all the cranial accessory fibres have been used up and some vagal fibres are also used up while supplying the pharynx, larynx and soft palate.
Therefore in the abdomen we have true vagal fibres.
What is the hypoglossal nerve in the neck?
This is a nerve of transit in the necl mostly.
What does the hypoglossal nerve supply?
It supplies almost all of the tongue muscles therefore it aims for the lingual artery and travels with its as a neurovascular bundle.
Describe the course of the hypoglossal nerve.
- leaves the cranial cavity through the hypoglossal canal
- takes a wide embracing route around the internal and external carotids and also outside the loop of the lingual artery
What fibres hitch hike along the hypoglossal nerve?
A few fibres from the first cervical ramus run with the hypoglossal nerve close to the skull base. These hitch hike along with the hypoglossal nerve for a while.
How the fibres from the first cervical vertebrae leave the hypoglossal nerve?
They leave the hypoglossal nerve as a slender filament called the superior root of the ansa cervicalis.