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The fibers carrying information from the skin, joints and muscles, discriminative touch sensation, proprioception, and vibration enter the dorsal aspect of the spinal cord in the medial position. These are the central processes of the sensory fibers whose cell bodies are located in the dorsal root ganglia.
After giving off local collaterals, including those responsible for spinal cord reflexes, the fibres ascend. The fibers from the lower part of the body, below the level of T6, form the medial gracilis fascicle (tract). The fibers above this level and those from the upper limb are added on laterally to form the cuneate fascicle (tract). Collectively these tracts are called the dorsal columns.
These tracts end in the lower medulla, where the fibers synapse in nuclei of the same name. The next group of fibers cross, and form a new pathway called the medial lemniscus which goes to the thalamus and then on to the somatosensory cortex.
Functionally, this pathway carries information with a high degree of retention of information and rapidly.