Summary and Revision of the Pharynx, Larynx and Neck

Question 1

What is the name of the 9th cranial nerve?

Answer 1

This is called the glossopharyngeal nerve.

Question 2

How does the glossopharyngeal nerve leave the skull?

Answer 2

Leaves the skull through the jugular foramen in the posterior cranial fossa.

Question 3

How many sensory ganglia does the glossopharyngeal nerve have?

Answer 3

It has 2.

Question 4

What do the sensory ganglia of the glossophayrngeal nerve contain?

Answer 4

They contain the cell bodies of the sensory nerve fibres.

Question 5

Where do the sensory ganglia of the glossopharyngeal nerve lie?

Answer 5

One lies in the jugular foramen and one lies just below the jugular foramen.

Question 6

How does the glossopharyngeal nerve pass down the neck?

Answer 6

It passes down the neck between the internal and external carotid arteries.

Question 7

As the glossopharyngeal nerve is travelling down the neck what is it travelling with?

Answer 7

It is travelling with the stylopharyngeus muscle which it also supplies.

Question 8

Describe the path of the glossopharyngeal nerve after it supplies the stylopharyngeus.

Answer 8

Passes between the superior and middle constrictor muscles and enters the side of the pharynx deep to the palatine tonsilar bed.

Question 9

Where does the glossopharyngeus run to from the palatine tonsilar bed?

Answer 9

It runs to the back of the tongue.

Question 10

Where does a branch of the glossopharyngeal nerve from the inferior sensory ganglion pass up to?

Answer 10

It passes up to the middle ear cavity.

Question 11

What does the branch of the glossopharyngeal nerve from the inferior sensory ganglia pass reform as on the medial wall of the cavity?

Answer 11

It reforms as the lesser superficial petrosal nerve.

Question 12

How does the lesser superior petrosal nerve run out of the skull?

Answer 12

It runs through the front of the petrous temporal bone and then down and out of the skull against through the foramen ovale.

Question 13

What receptors do the glossopharyngeal nerve supply?

Answer 13

They supply the baroreceptors in the region of the carotid sinus and the chemoreceptors in the carotid body.

Question 14

What do the pharyngeal branches of the glossopharyngeal nerve contribute to?

Answer 14

They contribute sensory nerve fibres to the pharyngeal plexus.

Question 15

What part of the pharynx is the glossopharyngeal nerve sensory to?

Answer 15

It is sensory to the back of the oropharynx.

Question 16

How can we test the glossopharyngeal nerve?

Answer 16

By stimulating the back of the oropharynx – gag reflex that results tells us that the sensory nerve supply to this region is still intact.

Question 17

What is the 10th cranial nerve?

Answer 17

The vagus nerve.

Question 18

How does the vagus nerve leave the skull?

Answer 18

It passes out of the skull through the jugular foramen.

Question 19

How many ganglia does the vagus nerve contain?

Answer 19

It has 2 ganglia.

Question 20

What type of cell bodies do the ganglia of the vagus nerve contain?

Answer 20

They contain the cell bodies of the sensory nerve fibres of the vagus.

Question 21

How does the vagus nerve pass down the neck?

Answer 21

It passes down the neck in the carotid sheath, first it travels with the internal carotid artery and then it travels with the common carotid artery.

Question 22

What is the first branch of the vagus nerve?

Answer 22

The auricular branch.

Question 23

What does the auricular branch of the vagus nerve supply?

Answer 23

It runs through the petrous temporal bone and supplies the skin behind the ear and the posterior wall of the external auditory meatus.

Question 24

What can happen if we irritate the auricular branch of the vagus nerve in an operation involving the ear?

Answer 24

This could cause vomiting through the vagal reflex.

Question 25

What is the contribution of the vagus nerve to the pharyngeal plexus?

Answer 25

Pharyngeal branches of the vagus nerve contribute motor nerve fibres to the pharyngeal plexus.

Question 26

What muscle do the pharyngeal muscles of the vagus nerve supply motor nerve fibres to?

Answer 26

levator palati muscle.

Question 27

Where does the superior laryngeal nerve arise? (branch of the vagus)

Answer 27

Arises high in the neck and travels down behind the internal carotid artery.

Question 28

What does the superior laryngeal nerve divide into after travelling behind the internal carotid artery?

Answer 28

It divides into the external laryngeal nerve and the internal laryngeal nerve.

Question 29

What is the external laryngeal nerve motor to?

Answer 29

It is motor to the cricothyroid muscle.

Question 30

What is the internal laryngeal nerve sensory to?

Answer 30

It is sensory to the mucosa of the larynx above the level of the vocal folds.

Question 31

Where does the main vagal trunk pass into?

Answer 31

It passes into the thoracic inlet and it can be found in the thorax, lying against the trachea on the right and on the aortic arch on the left.

Question 32

Where do the reccurent laryngeal nerves recur?

Answer 32

They recur around the aorta on the left and the subclavian artery on the right.

Question 33

What do the recurrent laryngeal nerves supply?

Answer 33

They supply all of the intrinsic muscles of the larynx except for the cricothyroid and sensation to the mucous membrane of hte larynx below the level of the vocal folds.

Question 34

How can we test the vagus nerve in the neck?

Answer 34

By asking the subject to raise their soft palate by saying ahhh and then to swallow to test that their sensory nerve supply to the pirifirom fossa and epiglottis is intact.

Question 35

What is the 11th cranial nerve called?

Answer 35

This is called the accessory nerve.

Question 36

Where does the accessory nerve arise from?

Answer 36

spinal accessory - arises from the upper cervical spinal segments cranial accessory - arises from the medulla

Question 37

How does the spinal accessory nerve pass into the posterior cranial fossa?

Answer 37

It passes up through the foramen magnum and into the posterior cranial fossa.

Question 38

How do both parts of the accessory nerve leave the posterior cranial fossa?

Answer 38

Through the jugular foramen.

Question 39

What else travels through the jugular foramen with the accessory nerve?

Answer 39

The vagus nerve and the glossopharyngeal nerve.

Question 40

What do the fibres of the cranial accessory nerve join?

Answer 40

They join the vagus nerve and are distributed to the pharyngeal plexus and through the laryngeal nerves with it.

Question 41

What does the spinal accessory nerve join?

Answer 41

It runs into the deep surface of the sternoclediomastoid supplies and supplies this muscle ith motor fibres. It runs out of the sternocleidomastoid muscle, across the posterior triangle of the neck and into the trapezius muscle - it also supplies the trapezius muscle.

Question 42

How can we test the spinal accessory nerve?

Answer 42

By asking the subject to shrug their shoulders against resistance from your hands and to turn their face against the palm of your hand. We can judge the force of each of the muscles this way. The right sternoclediomastoid muscle turns the face to the left.

Question 43

What is the name of the 12th cranial nerve?

Answer 43

The hypoglossal nerve.

Question 44

How does the hypoglossal nerve leave the skull?

Answer 44

It leaves the skull through the foramen magnum.

Question 45

Where does the hypoglossal nerve enter the hypoglossal canal?

Answer 45

Enters the hypoglossal nerve just above the occipital condyle.

Question 46

What is the path of the hypoglossal nerve?

Answer 46

It swings outwards and laterally behind the vagus and both the internal and external carotid arteries.

Question 47

What happens to the hypoglossal nerve at the level of the hyoid bone?

Answer 47

It runs forwards and joins the lingual artery

Question 48

What is the hypoglossal nerve a motor nerve to?

Answer 48

It is a motor nerve to all of the muscles of the tongue except the palatoglossus muscle.

Question 49

How can we test the hypoglossal nerve?

Answer 49

By testing the subject to stick their tongue out. The tongue will deviate to any side of the lesion of the hypoglossal nerve.