9.5 Trigeminal System

Question 1

What are the 3 divisions of the trigeminal nerve?

Answer 1

V1: Opthalmic
V2: Maxillary
V3: Mandibular

Question 2

What are the nuclei of the trigeminal nerve?

Answer 2

Trigeminal motor nuclei
Mesencephalic nucleus
Principal sensory nucleus
Spinal trigeminal nucleus

Question 3

Where do the 3 divisions meet?

Answer 3

Trigeminal/semilunar ganglion which is located in between 2 layers of the dura (Meckels cave) in the medial part of the middle cranial fossa just lateral to the cavernous tissue

Question 4

What are the cranial exits of teh 3 divisions?

Answer 4

V1: superior orbital fissure
V2: foramen rotundum - pterygopalatine fossa
V3: Foramen ovale

Question 5

what are the major branches of V1?

Answer 5

Frontal: sensory to forehead and eyelid
Lacrimal: lacrimal gland and lateral eyelid
Nasociliary: cornea and eye, nasal cavity, skin on external nose

Question 6

What is the passage of sympathetic innervation to the anterior face?

Answer 6

The sympathetic fibres join the long ciliary nerve in tenons capture of the cavernous sinus which are then carried forwards to the anterior eye and enter the eye et the level of the ciliary body

Question 7

Which branch of V1 receives parasympathetic information from VII?

Answer 7

Lacrimal

Question 8

What does the maxillary (V2) division carry with it and what does it do?

Answer 8

postganglionic, parasympathetic nerves from the pterygopalatine ganglion (VII) and distributes these to the lacrimal nerve and the nasal cavity

Question 9

Where do the sympathetics and parasympathetics synapse?

Answer 9

Symp: superior cervical ganglion
Para: pterygopalatine fossa

Question 10

What does the mandibular division supply?

Answer 10

Sensory: lower teeth, anterior 2/3 tongue (also taste fibres)
Motor: muscles of mastication, tensor tympani

Question 11

What is an important branch of the mandibular division?

Answer 11

Meningeal nerve - first branch after foramen ovale, goes back into the cranium and supplies the meninges

Question 12

Where does the trigeminal nerve attach to the brainstem?

Answer 12

Mid-lateral pons

Question 13

What is the trigeminal motor nucleus?

Answer 13

Contains the cell bodies of the muscles of mastication (bilateral input) and mediates the jaw jerk

Question 14

What is the mesencephalic nucleus and what is it the only example of and where does it send projections to?

Answer 14

proprioceptive nucleus only example of where cell bodies of sensory fibres are located in the brain - sends projections to the trigeminal motor nucleus

Receives information from jaw muscles and mechanoreceptors

Question 15

What is the principle sensory nucleus and where is it located?

Answer 15

Relays information about discriminitive touch and proprioceptive sensations (homologue of dorsal column)
Located in the mid pons at the level of the nerve, lateral to motor

Question 16

What is the spinal trigeminal nucleus and where does extend to-from

Answer 16

Processes information about pain and temperature from V1, 2, 3 and will blend into the dorsal horn of the spinal cord with the lower tract blending into Lissauer’s tract
Extends from mid-pons to C3 of spinal cord

Question 17

What are the 3 parts of the spinal trigeminal nucleus?

Answer 17

Oralis (med-pontin junction), interpolaris (open medulla) and caudalis (closed medulla)

Question 18

Which fibres join the spinothalamic pathway?

Answer 18

The spinal trigeminal pathway

Question 19

Which nucleus is the equivalent to the DC tract?

Answer 19

Spinal trigeminal nucleus

Question 20

Pain from which nerves map to trigeminal and where will it synapse?

Answer 20

C2, 3 dermatomes and myotomes, CN VII IX and X and branches of V
Will all synapse in the spinal trigeminal nucleus and map to VPM and S1