Posterior thoracic nucleus

Technopedia Center

Faculty of Engineering and Computer Science
S1 Informatics S1 Information Systems S1 Information Technology S1 Computer Engineering S1 Electrical Engineering S1 Civil Engineering

faculty of Economics and Business
S1 Management S1 Accountancy

Faculty of Letters and Educational Sciences
S1 English literature S1 English language education S1 Mathematics education S1 Sports Education

Posterior thoracic nucleus - Wikipedia

From Wikipedia, the free encyclopedia

(Redirected from Clarke's column)

Posterior thoracic nucleus
Diagram showing a few of the connections of afferent (sensory) fibers of the posterior root with the efferent fibers from the ventral column and with the various long ascending fasciculi. (Dorsal nucleus labeled at center right.)
Schematic of spinal cord grey matter showing location of the dorsal nucleus
Details
Identifiers
Latin	nucleus thoracicus posterior, nucleus dorsalis
TA98	A14.1.02.135
TA2	6074
FMA	73912
Anatomical terminology [edit on Wikidata]

The posterior thoracic nucleus, (Clarke's column, column of Clarke, dorsal nucleus, nucleus dorsalis of Clarke) is a group of interneurons found in the medial part of Rexed lamina VII, also known as the intermediate zone, of the spinal cord. It is located from the cervical segment C8 to lumbar segment L3 of the spinal cord and is an important structure for proprioception^[1] of the lower limb.

Anatomy

It occupies the medial part of the base of the posterior grey column and appears on the transverse section as a well-defined oval area.

It begins caudally at the level of the second or third lumbar nerve, and reaches its maximum size opposite the twelfth thoracic nerve. Above the level of the eight thoracic nerve its size diminishes, and the column ends opposite the last cervical or first thoracic nerve.

It is represented, however, in the other regions by scattered cells, which become aggregated to form a cervical nucleus opposite the third cervical nerve, and a sacral nucleus in the middle and lower part of the sacral region.

Nerve cells in the posterior thoracic nucleus are most abundant between the lower thoracic and upper lumbar segments. Cell bodies are of medium size and oval- or pyriform-shape. These cells characteristically present coarse Nissl granules and have characteristic eccentric nuclei.^[2]

Axonal projections from neurons in this nucleus give rise to the dorsal spinocerebellar tract which ascends ipsilaterally through the spinal cord and ends as mossy fibers in the ipsilateral cerebellar cortex after passing through the inferior cerebellar peduncle.^[3] Axons originating from the posterior thoracic nucleus which ascend contralaterally through the lateral funiculus of the spinal cord are named ventral spinocerebellar tract which cross over again within the white matter of the cerebellum, to ultimately end on its ipsilateral side.

Function

The posterior thoracic nucleus is a major relay center for unconscious proprioception. Sensory information from muscle spindles and tendon organs is carried by axons of larger neurons in dorsal root ganglia, which synapse onto neurons in the spinal cord including the posterior thoracic nucleus. From here information continues rostrally until it reaches the cerebellar cortex. This relay pathway is generally known as the dorsal spinocerebellar tract.

Diseases

It has been observed that in Friedreich's ataxia there is evident degeneration of the posterior thoracic nucleus as well as other proprioceptive spinal tracts. These patients might present with ataxia, dysarthria, muscle weakness or paralysis and skeletal defects.^[4]

Eponym

Clarke's column is named for Jacob Augustus Lockhart Clarke.^[5]^[6]

References

^ "SC 3. Dorsal Spinocerebellar Tract - Pathway". University of Wisconsin. Retrieved 4 May 2018.
^ Carpenter, Malcolm (1991). Core text of Neuroanatomy. Baltimore, Maryland: Williams & Wilkins. p. 70. ISBN 0683014579.
^ Blumenfeld, Hal (2010). Neuroanatomy through Clinical Cases. MA: Sinauer. pp. 709–710. ISBN 9780878930586.
^ Haines, Duane (2008). Neuroanatomy an Atlas of Structures, Sections and Systems. PA: Lippincott Williams & Wilkins. pp. 222–223. ISBN 978-0781763288.
^ synd/2143 at Who Named It?
^ "XXVI. Researches into the structure of the spinal chord". Philosophical Transactions of the Royal Society of London. 141: 607–621. 1851-12-31. doi:10.1098/rstl.1851.0029. ISSN 0261-0523.

External links

Spinal cord

General features

Grey columns

Posterior grey column	Marginal nucleus Substantia gelatinosa of Rolando Nucleus proprius Rexed lamina V Rexed lamina VI
Lateral grey column	Intermediolateral nucleus Posterior thoracic nucleus
Anterior grey column	Interneuron Alpha motor neuron Onuf's nucleus Gamma motor neuron
Other	Rexed laminae Central gelatinous substance Gray commissure

White matter

Sensory

Posterior	Posterior column-medial lemniscus pathway Gracile Cuneate
Lateral	Spinocerebellar dorsal ventral Spinothalamic lateral anterior Posterolateral Spinotectal
Anterior	Spinoreticular tract Spino-olivary tract

Motor

Lateral	Corticospinal Lateral Extrapyramidal Rubrospinal Raphespinal Reticulospinal Hypothalamospinal
Anterior	Corticospinal Anterior Extrapyramidal Vestibulospinal Reticulospinal Tectospinal Raphespinal Olivospinal

Both

Anterior white commissure

External features

Ventral
- Anterior median fissure
- Anterolateral sulcus
Dorsal
- Posterior median sulcus
- Posterolateral sulcus

Brain and spinal cord: neural tracts and fasciculi

Sensory

DCML

1°:	Pacinian corpuscle/Meissner's corpuscle → Posterior column (Gracile fasciculus/Cuneate fasciculus) → Gracile nucleus/Cuneate nucleus
2°:	→ sensory decussation/arcuate fibers (Posterior external arcuate fibers, Internal arcuate fibers) → Medial lemniscus/Trigeminal lemniscus → Thalamus (VPL, VPM)
3°:	→ Posterior limb of internal capsule → Postcentral gyrus

Anterolateral/
pain

Fast/lateral	1° (Free nerve ending → A delta fiber) → 2° (Anterior white commissure → Lateral and Anterior Spinothalamic tract → Spinal lemniscus → VPL of Thalamus) → 3° (Postcentral gyrus) → 4° (Posterior parietal cortex) 2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum)
Slow/medial	1° (Group C nerve fiber → Spinoreticular tract → Reticular formation) → 2° (MD of Thalamus) → 3° (Cingulate cortex)

Motor

Pyramidal

flexion: Primary motor cortex → Posterior limb of internal capsule → Decussation of pyramids → Corticospinal tract (Lateral, Anterior) → Neuromuscular junction

Extrapyramidal

flexion:	Primary motor cortex → Genu of internal capsule → Corticobulbar tract → Facial motor nucleus → Facial muscles
flexion:	Red nucleus → Rubrospinal tract
extension:	Vestibulocerebellum → Vestibular nuclei → Vestibulospinal tract
extension:	Vestibulocerebellum → Reticular formation → Reticulospinal tract
Midbrain tectum → Tectospinal tract → muscles of neck

Basal ganglia

direct:	1° (Motor cortex → Striatum) → 2° (GPi) → 3° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 4° (Thalamocortical radiations → Supplementary motor area) → 5° (Motor cortex)
indirect:	1° (Motor cortex → Striatum) → 2° (GPe) → 3° (Subthalamic fasciculus → Subthalamic nucleus) → 4° (Subthalamic fasciculus → GPi) → 5° (Lenticular fasciculus/Ansa lenticularis → Thalamic fasciculus → VL of Thalamus) → 6° (Thalamocortical radiations → Supplementary motor area) → 7° (Motor cortex)
nigrostriatal pathway:	Pars compacta → Striatum

Cerebellar

Afferent

Vestibular nuclei → Vestibulocerebellar tract → ICP → Cerebellum → Granule cell

Pontine nuclei → Pontocerebellar fibers → MCP → Deep cerebellar nuclei → Granule cell

Inferior olivary nucleus → Olivocerebellar tract → ICP → Hemisphere → Purkinje cell → Deep cerebellar nuclei

Efferent

Dentate nucleus in Lateral hemisphere/pontocerebellum → SCP → Dentatothalamic tract → Thalamus (VL) → Motor cortex

Interposed nucleus in Intermediate hemisphere/spinocerebellum → SCP → Reticular formation, or → Cerebellothalamic tract → Red nucleus → Thalamus (VL) → Motor cortex

Fastigial nucleus in Flocculonodular lobe/vestibulocerebellum → Vestibulocerebellar tract → Vestibular nuclei

Bidirectional:
Spinocerebellar

Unconscious proprioception	lower limb → 1° (muscle spindles → DRG) → 2° (Posterior thoracic nucleus → Dorsal/posterior spinocerebellar tract → ICP → Cerebellar vermis) upper limb → 1° (muscle spindles → DRG) → 2° (Accessory cuneate nucleus → Cuneocerebellar tract → ICP → Anterior lobe of cerebellum)
Reflex arc	lower limb → 1° (Golgi tendon organ) → 2° (Ventral/anterior spinocerebellar tract→ SCP → Cerebellar vermis) upper limb → 1° (Golgi tendon organ) → 2° (Rostral spinocerebellar tract → ICP → Cerebellum)

Category:

Spinal cord

Hidden categories: