Cranial nerve V and ophthalmic division

Question 1

Where are preganglionic neurones of sympathetic nervous system located?

Answer 1

Between T1-L2 spinal cord in the lateral horn.

Question 2

Where are postganglionic sympathetic cell bodies located?

Answer 2

In the sympathetic chain

Question 3

How is sympathetic drive supplied to the head?

Answer 3

Via the ICA

Question 4

Which cranial nerves can be sympathetic?

Answer 4

None, cranial nerves III, VII, IX and X can carry a parasympathetic component.
However they can carry sympathetic fibres in their distal branches, just not from their nucleus.

Question 5

Can the trigeminal nerve carry parasympathetic fibres?

Answer 5

Yes, parasympathetic travel with V1 (which arise from CNIII and CNVII)
Thus lesions of the trigeminal nerve fibres can lead to disturbances of sympathetic function in the face region. Autonomic fibres do not originate from the trigeminal nerve.

Question 6

Where do sympathetic efferents arise from?

Answer 6

Superior cervical ganglion

Question 7

Where do the divisions of trigeminal sensory fibres cover?

Answer 7

Ophthalmic area covers the forehead, eyes, superior eyelid, dorsum of nose
Maxillary area covers the Infraorbital region, nostrils, cheeks, lower eyelid and upper lip
Mandibular area covers the mandible, temporal region, region anterior to the ear

Question 8

Which part of the mandible is not supplied by the trigeminal nerve and what is it supplied by?

Answer 8

Angle of the mandible is supplied by branches of the cervical plexus.

Question 9

What internal structures does the trigeminal nerve provide sensation to?

Answer 9

The mucosa surrounding the nasal cavity, oral cavity, paranasal sinuses and parts of the dura mater.

Question 10

Only the mandibular division carries motor function. What muscles does it supply?

Answer 10

Mesoderm structures of the 1st pharyngeal arch.
Muscles of mastication, anterior belly of digastric mylohyoid, tensor veli palatini, tensor tympani

Question 11

What is the motor trigeminal nucleus?

Answer 11

Trigeminal motor nucleus in the pons

Question 12

What are the 3 sensory trigeminal nuclei?

Answer 12

Mesencephalic trigeminal nucleus - midbrain
Chief (principal/main) nuclei - pons
Spinal trigeminal nucleus - medulla oblongata

Question 13

Where do other trigeminal afferents have their cell bodies?

Answer 13

In the trigeminal ganglion within Meckel’s cave.

Question 14

What fibres enter the mesencephalic trigeminal nucleus?

Answer 14

Proprioceptive fibres from all 3 divisions.

Question 15

What fibres does the main sensory nucleus receive?

Answer 15

Touch and pressure sensation from all 3 divisions

Question 16

What fibres does the spinal trigeminal nucleus receive?

Answer 16

Pain and temperature from all 3 divisions, as well as some from CNIX and CNX.

Question 17

Which trigeminal nucleus is involved with the trigeminothalamic tract?

Answer 17

In the sensory nuclei, primary afferents synapse with the 2nd order neurone to progress to the somatosensory cortex via the trigeminothalamic tract.

Question 18

Where is the trigeminal ganglion located?

Answer 18

Middle cranial fossa in the Meckel’s cave.

Question 19

The motor root is smaller than the sensory trigeminal root. Why are they different?

Answer 19

Because the motor root comes from the neural cord and the sensory root from neural crest cells.

Question 20

What is Horner’s syndrome?

Answer 20

Caused by damage to sympathetic innervation, affecting eyelid and pupil of the eye.
Partial (ptosis) drooping of the upper eye. Partial since levator palpebrae superioris is innervated by oculomotor, so not full ptosis. Fixed constricted pupil of the eye on the same side as the drooping eyelids due to damaged autonomic fibres. Facial anhydrosis - lack of sweating on affected side.

Question 21

What is Harlequin syndrome?

Answer 21

Failure to sweat in the head region, particularly the face due to damage to sympathetic innervation, probably around the level of the neck distally. Typically constant vasodilation of hemiface on the side of lesion and failure to sweat. Pupil not often affected.

Question 22

What is trigeminal neuralgia?

Answer 22

Severe pain in one or more divisions of the trigeminal nerve.

Question 23

What are face shingles?

Answer 23

Shingles or Herpes Zoster
Reactivation of the herpes virus that causes chicken pox. Can affected any sensory nerve causing a band rash following a dermatome. Typically V1 or thoracic dermatome.

Question 24

Where does the ophthalmic division provide sensation to?

Answer 24

Skin - scalp, forehead, upper eyelids and dorsum of nose
Eye - cornea, conjunctiva, lacrimal glands and lacrimal apparatus

Question 25

What will the ophthalmic division branch into, before the superior orbital fissure?

Answer 25

After travelling through cavernous sinus, it gives off a tentorial branch which will innervate part of the dura. It then branches into the frontal, nasociliary and lacrimal branches.

Question 26

Are the 3 terminal branches of CNV1 outside, inside/through the tendinous ring?

Answer 26

Frontal is outside the tendinous ring
Nasociliary is through/inside
Lacrimal is outside

Question 27

What does the frontal nerve split into?

Answer 27

Supraorbital and supratrochlear nerves

Question 28

What does the frontal nerve give sensation to?

Answer 28

Frontal sinus and the forehead skin

Question 29

Where is the frontal nerve found?

Answer 29

Enters supraorbital fissure outside common tendinous ring and is superficial to the levator palpebrae superioris.

Question 30

Where does the nasociliary nerve enter the orbit?

Answer 30

Enters orbit via DOF lateral to the optic nerve. Crosses optic nerve to travel along medial wall between medial rectus and superior oblique.

Question 31

What branches does the nasociliary nerve give off?

Answer 31

Sensory root of ciliary ganglion
Short and long ciliary nerves
Infratrochlear nerve
Posterior and anterior ethmoidal nerves

Question 32

What does the infratrochlear nerve supply?

Answer 32

Skin of eyelid, bridge of nose, conjunctiva, lacrimal sac

Question 33

What does the posterior ethmoidal nerve supply?

Answer 33

Posterior ethmoidal air cells and sphenoid sinus

Question 34

What does the anterior ethmoidal nerve supply?

Answer 34

Anterior and middle ethmoidal air cells

Question 35

What does the lacrimal nerve supply?

Answer 35

The lacrimal gland, conjunctiva and upper eyelid

Question 36

How does the lacrimal nerve travel?

Answer 36

Travels laterally on top of the lateral rectus with lacrimal artery to reach the lacrimal gland. Postganglionic parasympathetic secretomotor fibres from CNVII reach the lacrimal gland via travelling with the lacrimal nerve.

Question 37

What is the corneal reflex and how is it tested?

Answer 37

Important reflex to protect the eyes. Cornea is lightly brushed with damp cotton wool.

Question 38

What nerves does the corneal reflex involve?

Answer 38

Clinical assessment of CNV1. Links CNV to CNVII. Sensory limb is CNV and motor limb is CNVII. When cornea is brushes CNV sends sensory information to the trigeminal nucleus. Signals via an interneuron to the facial motor nuclei of CNVII. Signal is sent bilaterally to the orbicularis oculi to firmly shut the eyes (blink)

Question 39

What happens to the corneal reflex is there is a lesion in either nerve involved?

Answer 39

Loss of the reflex