Cuneate fasciculus

The cuneate fasciculus is the tract or bundle that consists of first-order neurons of the dorsal column-medial lemniscal pathway, responsible for transmitting sensory information—including vibration, conscious proprioception, and two-point discrimination—from the upper extremities (excluding the head). It is present only at spinal segment levels T6 and above, as it carries sensory input exclusively from the upper body. The cuneate fasciculus ascends through the dorsal spinal cord and medulla, terminating by synapsing with neurons in the cuneate nucleus located within the cuneate tubercle in the lower medulla.

It is essential to distinguish the cuneate fasciculus from the gracile fasciculus, which is also part of the dorsal column-medial lemniscal pathway. The gracile fasciculus transmits similar sensory modalities, but from the lower extremities. Unlike the cuneate fasciculus, the gracile fasciculus extends throughout the spinal cord, including segments T6 and below. Additionally, the gracile fasciculus remains medial to the cuneate fasciculus along their course and terminates in the gracile nucleus within the gracile tubercle in the lower medulla.

A posterior intermediate sulcus separates the cuneate and gracile fasciculi along their length.