The fasciculus gracilis (tract of Goll or gracile fasciculus) is a bundle of axon

Axon

An axon is a long, slender projection of a nerve cell, or neuron, that conducts electrical impulses away from the neuron's cell body or soma....

 fibres in the posterior column of the spinal cord

Spinal cord

The spinal cord is a long, thin, tubular bundle of nervous tissue and support cells that extends from the brain . The brain and spinal cord together make up the central nervous system...

 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 up the spinal cord.

Function

The fasciculus gracilis provides proprioception

Proprioception

Proprioception , from Latin proprius, meaning "one's own" and perception, is the sense of the relative position of neighbouring parts of the body and strength of effort being employed in movement...

 of the lower limbs and trunk to the brain stem

Brain stem

In vertebrate anatomy the brainstem is the posterior part of the brain, adjoining and structurally continuous with the spinal cord. The brain stem provides the main motor and sensory innervation to the face and neck via the cranial nerves...

.

Additional functions of the fasciculus gracilis include carrying deep touch, vibrational, and visceral pain information to the brain stem. The fasciculus gracilis and the cuneate fasciculus offer the same functions but can be differentiated by the vertebral level at which information is provided. The cuneate fasiculus carries information from vertebral level T6 and up, while the fasiculus gracilis carries information from vertebral levels below T6. The two ascending tracts, however, do meet at the T6 level.

Damage to either of these tracts can result in a permanent loss of sensation in the limbs. See Brown-Séquard syndrome

Brown-Séquard syndrome

Brown-Séquard syndrome, also known as Brown-Séquard's hemiplegia and Brown-Séquard's paralysis, is a loss of sensation and motor function that is caused by the lateral hemisection of the spinal cord...

.

Pathway

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

Medulla oblongata

The medulla oblongata is the lower half of the brainstem. In discussions of neurology and similar contexts where no ambiguity will result, it is often referred to as simply the medulla...

 of the brainstem.

Second-order fibers: found in the medulla

Medulla

Medulla refers to the middle of something and derives from the Latin word for marrow. Its anatomical uses include:* Medulla oblongata, a part of the brain stem* Renal medulla, a part of the kidney* Adrenal medulla, a part of the adrenal gland...

; decussate in the medulla and, together with the second-order fibers of the cuneate fasiculus, create nerve fiber tracts called the medial lemniscus

Medial lemniscus

The medial lemniscus, also known as Reil's band or Reil's ribbon, is a pathway in the brainstem that carries sensory information from the gracile and cuneate nuclei to the thalamus.-Path:...

, 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.

Additional Information

The fasciculus gracilis is wedge-shaped on transverse section and lies next to the posterior median septum, its base being at the surface of the medulla spinalis, and its apex directed toward the posterior gray commissure. The fasiculus gracilis increases in size from anterior to superior.

The tract of Goll, or the common name of the fasiculus gracilis, was named after Swiss neuroanatomist Friedrich Goll (1829–1903).