Cuneate fasciculus
The cuneate fasciculus, also known as the fasciculus cuneatus (plural: fasciculi cuneati) or column of Burdach, represents the lateral portion of the dorsal columns and carries input from between and including C1 and T6 .
Function
The cuneate fasciculus is responsible for transmitting vibration, conscious proprioception, and fine (discriminative) touch sensations from the upper body .
Gross anatomy
Peripheral connections
First-order neurons from peripheral receptors enter the spinal cord via the posterior roots, and unlike first-order neurons from the spinothalamic tract, do not synapse in the posterior posterior grey horn of the cord . Thus, these first-order neurons form the cuneate fasciculus of the dorsal columns if input was from between and including C1 and T6 . If input is from T7 or below, the gracile fasciculus is formed instead, which is discussed separately.
Course
Unlike fibers of the spinothalamic tract, these first-order neurons in the cuneate fasciculus continue to ascend without decussation . This ipsilateral ascension continues until the medulla oblongata of the brainstem . Fibers of this tract are somatotopically organized for their entire course .
Upon reaching the cuneate nucleus of the caudal medulla oblongata these first-order neurons terminate and synapse with second-order neurons . These second-order neurons then decussate to the contralateral side, known as the internal arcuate fibers during this decussation . These decussated neurons continue to ascend as part of the medial lemniscus where they terminate in the ventral posterior nucleus of the thalamus . Here, they synapse with third-order neurons . It is these third-order neurons that finally project to the primary somatosensory area on the ipsilateral side of the cerebral cortex .
Related pathology
- intramedullary spinal tumor
- spinal cord injury
- Brown-Séquard syndrome
- transverse myelitis
- multiple sclerosis
- subacute combined degeneration of the cord
- nitrous oxide toxicity
- copper deficiency myeloneuropathy
- neurosyphilis (tabes dorsalis)
- HIV vacuolar myelopathy
History and etymology
Named after Karl Friedrich Burdach (1776-1847), German anatomist
See also
- gracile fasciculus (or column of Goll)
Siehe auch:
Assoziationen und Differentialdiagnosen zu Fasciculus cuneatus: 