Cranial nerves III

Question 1

what are the sensory nuclei of the trigeminal nerve? where are they located specifically?

Answer 1

1. mesencephalic - midbrain 2. principal (main) - midpons 3. spinal - pons, medulla, C1-2/3

Question 2

what are the functions of the trigeminal sensory nuclei?

Answer 2

1. mesencephalic - general proprioception 2. main - discriminatory touch 3. spinal - nociceptive, tactile, and thermal sensation

Question 3

where is the motor nucleus of the trigeminal located?

Answer 3

midpons

Question 4

what are the components of the discriminatory touch pathway from the orofacial region?

Answer 4

trigeminal ganglion (1st order) - main sensory nucleus (2nd order) - dorsal trigeminal lemniscus - VPM of thalamus (3rd order) - postcentral gyrus

Question 5

what are the components of the pain and temperature pathway from the orofacial region?

Answer 5

trigeminal ganglion (1st order) - spinal tract - spinal nucleus (2nd order) - ventral trigeminal lemniscus - VPM of thalamus (3rd order) - postcentral gyrus / anterior cingulate / anterior insular cortices

Question 6

what are the components of the general proprioception pathway from the orofacial region?

Answer 6

mesencephalic nucleus (1st order) - branches of trigeminal nerve - main sensory nucleus (sensation) / motor nucleus (reflex)

Question 7

what is the role of the trigeminal in the corneal blink reflex?

Answer 7

1. afferent limb - opthalmic division 2. efferent limb - facial nerve

Question 8

what is the result of damage to the mandibular division of the trigeminal?

Answer 8

reduced sensation over V3 area, jaw deviation to side of lesion

Question 9

what is the result from a lesion to the spinal tract and/or spinal V nucleus between the midpons and C2/3?

Answer 9

1. loss of pain and temperature sensation 2. dimunition of tactile sense IPSILATERAL orofacial region and GSA territory of CN 7, 9, 10

Question 10

what is the result of a lesion to the ventral V lemniscus?

Answer 10

1. loss of pain and temperature sensation 2. dimuniation of tactile sense CONTRALATERAL orofacial region and GSA territory of CN 7, 9, 10

Question 11

what is the result of a lesion to the dorsal V lemniscus between the midpons and thalamus?

Answer 11

partial dimunition of tactile sense from ipsilateral orofacial region