gracile fasciculus

Spinal cord

with nerves (Section)

The gracile fasciculus, also known as the fasciculus gracilis (plural: fasciculi graciles) or column of Goll, represents the medial portion of the dorsal columns and carries input from below and including T7 .

Function

The gracile fasciculus is responsible for transmitting vibration, conscious proprioception, and fine (discriminative) touch sensations from the lower 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 gracile fasciculus of the dorsal columns if input was from T7 or below . If input is from between and including C1 and T6, the cuneate fasciculus is formed instead, which is discussed separately.

Course

Unlike fibers of the spinothalamic tract, these first-order neurons in the gracile 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 gracile 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

History and etymology

Named after Friedrich Goll (1829-1903), a Swiss anatomist .