Gracile fasciculus

Gracile fasciculus
Gracile fasciculus is labeled in blue at upper right.
Diagram of the principal fasciculi of the spinal cord.
Details
Identifiers
Latin	Fasciculus gracilis medullae spinalis
NeuroLex ID	nlx_144039
TA	A14.1.02.243 A14.1.04.018 A14.1.04.107
FMA	73938
Anatomical terms of neuroanatomy []

The gracile fasciculus (fasciculus gracilis or tract of Goll) is a bundle of axon fibers in the posterior column-medial lemniscus pathway of the spinal cord and carries information from the middle thoracic and lower limbs of the body. The gracile fasiculus is one of many ascending tracts, which carry received sensory information to the brain via the spinal cord.

The gracile fasciculus provides conscious proprioception of the lower limbs and trunk to the brainstem.

Additional functions of the gracile fasciculus include carrying deep touch, vibrational, and visceral pain information to the brainstem. The gracile fasciculus and the cuneate fasciculus offer the same functions but can be differentiated by the vertebral level at which information is provided. The cuneate fasciculus carries information from vertebral level T6 and above, and the gracile fasciculus carries information from vertebral levels T7 and below. The two ascending tracts meet at the T6 level.

Ascending tracts typically have three levels of neurons that relay information from the physical point of reception to the actual point of interpretation in the brain. The fasciculus gracilis has first-order, second-order, and third-order nerve fibers described below:

First-order fibers: found on the ipsilateral side of the spinal cord; ends at the gracile nucleus in medulla oblongata of the brainstem.

Second-order fibers: found in the medulla; decussate in the medulla as internal arcuate fibers and, together with the second-order fibers of the cuneate fasiculus, create nerve fiber tracts called the medial lemniscus, which relays the information received from the first-order neurons to the thalamus.

Third-order fibers: fibers which relay the signal received from the medial lemniscus at the thalamus to the cerebral cortex.