Posterior funiculus

The posterior funiculus, a.k.a. posterior column or dorsal column, is a region of sensory white matter located between the posterior median sulcus at the midline and the entry points of the posterior nerve rootlets into the spinal cord, i.e. the posterolateral sulcus. It forms an integral component of the dorsal column-medial lemniscal pathway, which facilitates the transmission of vibration, fine touch, proprioception, and two-point discrimination sensations from the periphery to the brain.

This posterior funiculus (or dorsal column) can be divided into two fasciculi: the gracile fasciculus, which lies medially and transmits sensory signals from the lower body (below the T6 spinal segment level), and the cuneate fasciculus, positioned laterally and responsible for similar sensory input from the upper body (above the T6 level). An intermediolateral sulcus anatomically separates these two fasciculi. Both represent the first-order neurons of the dorsal column-medial lemniscal sensory pathway.

As the sensory fibers ascend through the posterior funiculus, they remain uncrossed until they synapse in the nucleus gracilis and nucleus cuneatus located within the caudal medulla. From there, the fibers decussate as internal arcuate fibers and continue through the brainstem as the medial lemniscus. The sensory information is ultimately conveyed to the thalamus and projected to the primary sensory cortex.