Summary and Revision of the Infratemporal Fossa, Nose, Mouth and Face

Question 1

Where does the second division of the trigeminal nerve - the maxillary division - run?

Answer 1

They run in the lateral wall of the cavernous sinus.

Question 2

Where is the maxillary nerve a sensory nerve to?

Answer 2

It is the sensory nerve to the midface, nasal cavity and palate as well as to the lower eyelid and associated conjunctiva.

Question 3

What are the branches of the maxillary division in the pterygopalatine fossa called?

Answer 3

• infraorbital – run forwards into the cheek
• greater palatine – run downwards into the hard and soft palate
• nasopalatine – into the nose and roof of the nasopharynx.

Question 4

What branches of the maxillary division are give off in the infratemporal fossa?

Answer 4

Alveolar branches.

These pass inferiorly to the maxillary teeth and the maxillary antrum.

Question 5

What is the maxillary division entirely?

Answer 5

It is entirely sensory.

Question 6

What do each of the branches of the maxillary division pick up?

Answer 6

They pick up postganglionic parasympathetic secretomotor fibres from the greater superficial petrosal branch of the facial nerve that have synapsed in the pterygopalatine ganglion.

These postganglionic fibres travel with the branches of the mandibular division to glands in the nasal mucosa and on the palate.

Question 7

How can we test the maxillary nerve?

Answer 7

Through response to touch, pressure, pain and temperature over its distribution on the cheek, temple, upper lip and lower eyelid.

Question 8

What does the mandibular division of the trigeminal nerve pass through and what does it enter?

Answer 8

It passes through the foramen ovale and then it enters the roof of the infratemporal fossa.

Question 9

What does the anterior division of the mandibular branch of the trigeminal nerve give?

Answer 9

It gives motor branches to all the muscles of mastication and to the tensor tympani and the tensor palati muscles.

It gives 1 sensory branch to the inside of the cheek called the long buccal branch.

Gives another small spinous branch which runs up with the middle meningeal artery.

Question 10

What does the small spinous branch supply?

Answer 10

It supplies dura in the middle cranial fossa and helps to supply the mucous membrane of the mastoid air cells.

Question 11

What does the posterior division of the mandibular nerve divide into?

Answer 11

It divides into:

• auriculotemporal nerve
• inferior alveolar nerve
• lingual nerve
• a small motor branch to the mylohyoid and anteriro belly of the digastric muscle

Question 12

What is the path of the auriculotemporal nerve?

Answer 12

It passes laterally and splits to pass either side of the middle meningeal artery.

Question 13

What does the auriculotemporal nerve supply?

Answer 13

It supplies the skin of the temple, scalp and front of the auricle here and the anterior portion of the external auditory meatus.

Question 14

What does the auriculotemporal nerve pick up?

Answer 14

It picks up the postganglionic parasympathetic fibres from the lesser superficial petrosal branch of the glossopharyngeal nerve that have synapsed in the otic ganglion and then carries these branches to the parotid gland.

Question 15

What does the inferior alveolar nerve supply?

Answer 15

It supplies the pulp caivities of the teeth with sensation and then it emerges through the mental foramen as the mental nerve to supply the skin and mucous membrane of the lower lip and the skin over the chin.

Question 16

Describe the path of the lingual nerve.

Answer 16

• runs over the lateral surface of the medial pterygoid muscle
• runs on to the bone of the mandible where it lies just beneath the third molar tooth roots
• passes medially across the floor of the mouth
• hooks under the submandibular duct before it runs up into the substance of the tongue

Question 17

Where does the lingual nerve carry generation sensation to?

Answer 17

It carries general sensation to the anterior 2/3 of the tongue.

Question 18

High in the infratemporal fossa, what is the lingual nerve joined by?

Answer 18

It is joined by the chorda tympani branch of the facial nerve.

Question 19

What does the chorda tympani carry?

Answer 19

It carries preganglionic parasympathetic nerve fibres to the submandibular ganglion which relay here and the postganglionic fibres continue as secretomotor nerves tot he submandibular and sublingual salivary glands.

Question 20

What is the path of taste sensation from the anterior 2/3 of the tongue?

Answer 20

Taste sensations from this part of the tongue joins the chorda tympani and runs back to the facial nerve in the middle ear.

Question 21

How can the mandibular nerve be tested?

Answer 21

It can be tested by asking a subject to bite their teeth together on both sides and to protrude the lower jaw.

We can test the sensory component of the nerve in the same way as the maxillary division over the dermatome of this nerve in the lower face.

Question 22

How does the facial nerve leave the skull?

Answer 22

It leaves the skull through the stylohyoid foramen.

Question 23

After leaving the skull, what does the facial nerve enter?

Answer 23

It enters the parotid gland and it runs forwards through the substance of the gland superficially.

Question 24

At the margins of the parotid gland, what does the facial nerve emerge as?

Answer 24

It emerges as temporal, zygomatic, buccal, marginal, mandibular and cervical branches. These are all motor nerves to the muscles of facial expression.

Question 25

How can we test the facial nerve?

Answer 25

By asking a subject to blink, screw their eyes up and show their teeth and/ or whistle.

Question 26

Where does the hypoglossal nerve lie in the neck?

Answer 26

It lies superficially in the neck, close to the lingual artery by the side of the hyoid bone.

Question 27

What is the path of the lingual artery?

Answer 27

It passes forwards and runs over the lateral aspect of the hypoglossus muscle in the floor of the mouth.

Question 28

Where do branches of the hypoglossal nerve run?

Answer 28

They run to each of the intrinsic and extrinsic muscles of the tongue, except for the palatoglossus.

Question 29

How can we test the hypoglossal nerve?

Answer 29

By asking a subject to stick their tongue out. When the hypoglossal nerve is defective then the tongue deviates to the side of the lesion when the hypoglossal nerve is ineffective.