Column of Clarke

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Column of Clarke
File:Gray669.png
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.)
Latin	nucleus thoracicus posterior, nucleus dorsalis
Gray's	subject #185 758
System
MeSH	[1]
Schematic of spinal cord grey matter showing location of the Dorsal Nucleus

Clarke's column (column of Clarke, dorsal nucleus, posterior thoracic nucleus) is a group of interneurons found in Lamina VII, also known as the intermediate zone, of the spinal cord.

Anatomy

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

It begins below 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 ninth 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 Clarke’s column are most abundant between the lower thoracic and upper lumbar segments. Cell bodies are of medium size and oval- or pyriform-shape. Some cells can be as large as anterior horn cells; the nuclei of these larger cells are often found on the periphery of the cell.

Function

Clarke’s column is a major relay center for unconscious proprioception. Sensory information for muscle spindles and tendon organs synapses onto posterior root ganglion, which in turn synapses onto Clarke’s column. From Clarke’s column, information continues rostrally until it reaches the cerebellar cortex. This relay pathway is generally known as the spinocerebellar tract.

Eponym

It is named for Jacob Augustus Lockhart Clarke.

External links

• http://isc.temple.edu/neuroanatomy/lab/atlas/L3/
• http://www.neuroanatomy.wisc.edu/sc97/text/p3/Pathway.htm

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