Several ascending and descending tracts are present in the spinal cord. The three most important tracts in the spinal cord are:
- Dorsal Column Medial Lemniscus Pathway - This is an ascending sensory tract.
- Spinothalamic Tract - This is an ascending sensory tract.
- Corticospinal Tract - This is a descending motor pathway which has upper motor neurons (UMN) and lower motor neurons (LMN).
The gracile nucleus, along with the cuneate nucleus, is a part of the dorsal column medial lemniscus pathway (DCML). The gracile nucleus situates in the midline dorsal medulla at the junction of the brainstem and the spinal cord. The gracile fasciculus carries sensory input from vertebral level T6 and below and ascends into the gracile nucleus to form the gracile tubercle. The cuneate fasciculus carries information from T6 and above and ascends into the cuneate nucleus to form the cuneate tubercle. These tubercles appear as bumps on the dorsal part of the medulla.