Trigeminal System N22 Flashcards
Origin of Sensory division of Trigeminal N.
Trigeminal ganglion –>
Spinal Trigeminal nucleus/tract
Chief (main/principle) sensory nucleus
Mesencephalic nucleus/tract
Origin of Motor division of Trigeminal N.
Motor nucleus of trigeminal n
Trigeminal n Sensory division function
GENERAL SOMATIC SINSIBILITY (vibration, touch, conscious and unconscious proprioception, pain and temperature)
Trigeminal n Motor division function
innervation of muscles of mastication (temporal is, masseter, medial/lateraly pterygoids, tensor tympani, tensor veli palatine, anterior digastric belly, mylohyoid)
Function of general somatic afferent (GSA) components of Trigeminal n.
General sensations of the face, nasal and oral cavities, dura mater and proprioception
GSA Nuclei (3)
Spinal Trigeminal Nucleus, Chief (main/principle) sensory nucleus, Mesencephalic nucleus
Which all form a continuous column of cells
Spinal Trigeminal Nucleus
Lateral tegmentum of medulla and caudal pons; considered to be a rostral continuation of the SUBSTANTIA GELATINOSA
Spinal Trigeminal Tract continuation of ______
Considered to be a rostral continuation of Lissauer’s Tract
Spinal Trigeminal Tract is analogous to _______
ANTEROLATERAL SYSTEM: pain, temperature, crude touch
Chief (Main/Principle) Sensory Nucleus
Located in the dorsolateral pontine tegmentum (midpons)
Chief Nucleus Function
Fine touch, 2-pt discrimination, vibration, conscious proprioception of head
Chief Nucleus is analogous to ________
DC-ML
Mesencephalic Nucleus location
Rostral pons and caudal midbrain
Mesencephalic Nucleus Function
UNCONSCIOUS PROPRIOCEPTION - acts as primary sensory ganglia (DRG)
Mesencephalic Nucleus is analogous to _____
Spinocerebellar System
Peripheral Sensory division is split into 3 divisions:
V1: opthalmic V2: maxillary V3: mandibular (NO overlap)
Trigeminal ganglion of the sensory root contains
Cell bodies of peripheral processes; in trigeminal cave (Meckel’s) in middle cranial fossa; acts like DRG
Trigeminal ganglion of motor root contains
Cell bodies for fibers in V3: mandibular division
Primary afferent axons will enter either
Chief sensory nucleus at same level (midpons) or descend to spinal trigeminal nucleus
Chief Nucleus receives which primary afferent axons
Large afferent inputs for fine touch, vibratory and conscious proprioception
Spinal Trigeminal Nucleus receives which primary afferent axons
Small afferent inputs for pain, temperature, and crude touch
Afferents path to synapse on Spinal trigeminal nucleus
descend lateral to spinal trigeminal nucleus as SPINAL TRACT OF TRIGEMINAL N (Sp V Tr)
Mesencephalic nucleus receives
afferents that travel from the periphery via mesencephalic tract for unconscious proprioception information from muscle spindles in the muscles of mastication
Motor Component fibers paths
Motor Trigeminal nucleus (pons)–> middle cerebellar peduncle –> V3
Motor trigeminal nucleus receives
bilateral cortical input
Ventral Trigeminothalamic Tract (VTTT) have fibers from which two nuclei
Spinal trigeminal and Chief sensory
VTTT fibers from Spinal Trigeminal Nucleus
Exit nucleus –> decussate –> ascend as VTTT (near ALS) –> VPM of thalamus –> lateral primary somatosensory cortex (3,1,2)
VTTT fibers from Spinal Trigeminal Nucleus carry
sensory information for slow, dull pain, and reflexes
Reflexes from VTTT spinal Trigeminal Nucleus synapse on
Reticular Formation
VTTT fibers from Chief Sensory Nucleus
Exit nucleus –> decussate –> ascend as VTTT (near ML) –> VPM of thalamus –> lateral primary somatosensory cortex (3,1,2)
VTTT fibers from Chief Sensory Nucleus carry
sensory information for 2-point discrimination, fien touch, vibration, conscious proprioception
Dorsal Trigeminothalamic Tract (DTTT)
small, IPSILATERAL, from chief nucleus to ipsilateral VPM
Processes leaving the Spinal trigeminal nucleus
- VTTT –> VPM of thalamus
- Reticular formation –> Intralaminar thalamic nuclei
- PAG and SC –> reflexive movement of head and control of pain
