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In neuroanatomy, the dorsal column nuclei are a pair of nuclei in the dorsal columns in the brainstem.[1] The name refers collectively to the cuneate nucleus and gracile nucleus, which are present at the junction between the spinal cord and the medulla oblongata. Both nuclei contain second-order neurons of the dorsal column-medial lemniscus pathway, which carries fine touch and proprioceptive information from the body to the brain. Each nucleus has an associated nerve tract, the gracile fasciculus and the cuneate fasciculus.

Dorsal column nuclei
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NeuroLex IDnlx_153860
Anatomical terms of neuroanatomy
Dorsal column nuclei
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Present at the junction between the spinal cord and medulla oblongata, the dorsal column nuclei consist of paired gracile, and cuneate nuclei (labels 6 and 7, respectively).
Details
SystemSomatosensory system
Identifiers
NeuroLex IDnlx_153860
Anatomical terminology


Contents

Nuclei and tractsEdit

The dorsal column nuclei also include their tracts.

Gracile nucleusEdit

The gracile nucleus is medial to the cuneate nucleus; its neurons receive afferent input from dorsal root ganglion sensory neurons subserving the lower trunk and limbs. The gracile nucleus and fasciculus carry epicritic, kinesthetic, and conscious proprioceptive information from the lower part of the body (below the level of T6 in the spinal cord). Because of the large population of neurons in the gracile nucleus they give rise to a raised area called the gracile tubercle on the posterior side of the closed medulla at the floor of the fourth ventricle.

Cuneate nucleusEdit

The counterpart to the gracile nucleus and fasciculus is the cuneate nucleus and fasciculus, which carries the same type of information, but from the upper body (above T6, excepting the face and ear - the information from the face and ear is carried by the principal sensory nucleus of trigeminal nerve. Due to the large number of neurons they give rise to the cuneate tubercle seen on viewing the posterior side of the brainstem.. The neurons of the cuneate nucleus receive connections from dorsal root neurons innervating the upper body.

Neurons of the dorsal column nuclei send axons that form the internal arcuate fibers, crossing over at the sensory decussation to form the medial lemniscus, ultimately synapsing with third-order neurons of the thalamus.

Additional imagesEdit

ReferencesEdit

  1. ^ Standring, Susan. Gray's anatomy: the anatomical basis of clinical practice (41 ed.). Elsevier Limited. pp. 309–330. ISBN 978-0-7020-5230-9.