Trigeminal lemniscus

Nerve tract
Trigeminal lemniscus
Details
Identifiers
Latinlemniscus trigeminalis
NeuroNames1572
TA98A14.1.05.310
A14.1.08.680
A14.1.06.208
TA25862
FMA84040
Anatomical terms of neuroanatomy
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The trigeminal lemniscus or trigeminothalamic tract is a somatosensory tract containing second-order neuron fibers of the trigeminal system. It consists of the ventral and dorsal trigeminal tracts. It consists of second-order sensory axons conveying tactile, pain, and temperature impulses from the skin of the face, the mucous membranes of the nasal and oral cavities, and the eye, as well as proprioceptive information from the facial and masticatory muscles.

It terminates by synapsing with third-order neurons in the ventral posteromedial nucleus of thalamus.

This tract was historically considered a cephalic division of the medial lemniscus due to the close proximity of the two ascending tracts.[1] Like the medial lemniscus in the dorsal column-medial lemniscus pathway (DCML), that carries mechanosensory information from part of the head and the rest of the body, the trigeminal lemniscus carries mechanosensory information from the face.[2] However, the trigeminal lemniscus also carries pain and temperature sensations from the contralateral orofacial region, just as the spinothalamic tract carries these sensations from the contralateral body. Thus, the trigeminal lemniscus of the head is functionally analogous to both the DCML tracts and the spinothalamic tract of the body.

Divisions

The trigeminal lemniscus contains two main divisions:

  • The ventral trigeminal tract - consists of second-order axons from the spinal trigeminal nucleus. These fibers cross the midline and ascend to the contralateral thalamus.
  • The dorsal trigeminal tract - consists of second-order axons from the principal sensory nucleus of trigeminal nerve. These fibers do not cross the midline, and ascend to the ipsilateral thalamus.

References

  1. ^ Anthoney, TR (1993). Neuroanatomy and the neurologic exam: a thesaurus of synonyms, similar-sounding non-synonyms, and terms of variable meaning. CRC Press.
  2. ^ Purves, Dale (2012). Neuroscience (5th ed.). Sinauer Associates. pp. 199–201. ISBN 9780878936953.

Sources

  • Anthoney, T. R. (1993). Neuroanatomy and the neurologic exam: a thesaurus of synonyms, similar-sounding non-synonyms, and terms of variable meaning.[1] CRC Press.
  • Snell, R. S. (2010). Clinical neuroanatomy. Lippincott Williams & Wilkins.
  • Miller MW, Muller SJ. Structure and histogenesis of the principal sensory nucleus of the trigeminal nerve: effects of prenatal exposure to ethanol. J Comp Neurol. 1989;282:570–580

[2]

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Anatomy of the pons
Dorsal/
(tegmentum)
Surface
White: Sensory
White: Motor
Grey: Cranial nuclei
afferent:
efferent:
Grey: Other nuclei
Ventral/
(base)
Grey
White: Motor/descending
Surface
Other grey: Raphe/
reticular
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  • t
  • e
Sensory
DCML
1°:
2°:
3°:
Anterolateral/
pain
Fast/lateral
Slow/medial
Motor
Pyramidal
Extrapyramidal
flexion:
flexion:
extension:
extension:
Basal ganglia
direct:
indirect:
nigrostriatal pathway:
Cerebellar
Afferent
Efferent
Bidirectional:
Spinocerebellar
Unconscious
proprioception
Reflex arc
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  • Terminologia Anatomica
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  1. ^ Anthoney, T.R. (1993). Neuroanatomy and the neurologic exam: a thesaurus of synonyms, similar-sounding non-synonyms, and terms of variable meaning. CRC Press.
  2. ^ Frost DO. Development of anomalous retinal projections to nonvisual thalamic nuclei in Syrian hamsters: a quantitative study. J Comp Neurol. 1986;252:95–105