Where are the cell bodies of CN 5 afferents primary located?
trigeminal/semilunar ganglion
What are the 4 major nuclei of the trigeminal tract?
- main/primary sensory nucleus (msT)
- trigmeninal motor nucleus (mT)
- spinal nucleus
- mesencephalic nucleus (mes)
Where is the main sensory nucleus (msT) found?
in the mid pons enlargement lateral to trigeminal motor nucleus (mT)
Which trigeminal nucleus extends rostrally?
Mesencephalic nucleus (mes)
Which trigeminal nucleus extends caudally into the cervical region?
Spinal nucleus
What afferents modalities are transmitted to the cortex via the primary sensory nucleus (msT)
discriminative tactile & proprioceptive senstations
What afferent modalities are transmitted via the spinal nucleus?
pain & temperature
What afferent modalities are transmitted via the mesencephalic nucleus (mes)?
proprioceptive afferents from the muscles of the mastication & the TMJ
Identify the following structures
- mesencephalonic nucleus
- main sensory nucleus
- trigeminal ganglion
- spinal (trigeminal) nucleus
What is the primary sensory afferent of the head and face?
Trigeminal nerve (V1, V2, V3); review distribution
What are the 2 divisions of the main sensory nucleus (msT)?
dorsomedial & ventrolateral divisions
What afferents are associated with the dorsomedial division of the msT
afferents from oral cavity
What afferents are assoicated with the ventrolateral division of the main sensory nucleus?
V1-V3
2nd order afferents of the msT nucleus project to what nucleus in the thalamus?
VPM
2nd order afferents from the ventrolateral division of the msT project to ____ VPM via what tract?
Contralateral VPM via the anterior trigeminothalamic tract
2nd order neurons from the dorsolateral division of the msT project to ___ VPM via what tract?
ipsilateral VPM via the posterior trigeminothalamic tract/ dorsal central trigeminal tract
fibers of the ventrolateral msT are joined by fibers from what other nuclei in the VPM?
spinal trigeminal nucleus to form the trigeminothalamic lemniscus
Through what brainstem structure does the dorsal central trigeminal tract ascend through?
The periaqueductal gray matter (surrounds cerebral aqueduct in the midbrain)
Where are tertiary neurons of the trigeminal pathway located?
cell bodies in the VPM and project to the primary somatosensory cortex
Tertiary neurons of the VPM project via what structure to reach the post-central gyrus?
The posterior limb of the internal capsule
What part of the head receives sensory innervation from the trigeminal nerve?
The anterior half
trigeminal afferents carrying pain & temp info enter ___ nucleus and then DESCEND via what tract?
enter spinal nucleus and DESCEND via spinal trigeminal tract before ascending via anterior trigeminothalamic tract
What are the 3 regions of the spinal nucleus?
- Pars/subnucleus CAUDALIS
- pars/subnucleus oralis
- pars/subnucleus interpolaris
-
How are the afferent TO the ventrolateral msT organized?
V1 =posterior, V2 = middle, V3 = anterior/ventral
how are the afferents in the ventrolateral msT organized
V1 = anterior, V2 = middle, V3 = posterior
What is the obex?
narrowing of the 4th ventricle as it becomes the central canal of the spinal cord
How are V1-V3 organized in the pars caudalis?
V1= most rostral, V2 = middle, V3 = most posterior
The most rostral portions of the pars caudalis are located near what structure?
The obex in the medulla
The most caudal portions of the pars caudalis are located where?
in the upper cervical cord (C1-C3 area)
Does damage to the pars caudalis presents with a characteristic or non-characteristic pattern of nociceptive and thermal sensory loss?
Characteristic d/t little other lap between V1-V3