Gracile tubercle
Tuberculum gracile
- Latin synonym: Tuberculum nuclei gracilis
Definition
Gracile tubercle appears as an elevation or a bump on the dorsal surface of the medulla oblongata, in the floor of the fourth ventricle. This prominence is formed by the underlying gracile nucleus, which is a key component of the dorsal column-medial lemniscal sensory pathway.
Lateral to the gracile tubercle lies the cuneate tubercle, a similar elevation also located in the floor of the fourth ventricle. This prominence is formed by the underlying cuneate nucleus, which, like the gracile nucleus, participates in the dorsal column-medial lemniscal pathway.
Both the gracile and cuneate nuclei relay sensory information such as vibration, conscious proprioception, and two-point discrimination. While these nuclei share functional roles within this pathway, they differ in their input sources: the gracile nucleus receives sensory input from the lower extremities, whereas the cuneate nucleus processes input from the upper extremities, excluding the head.
References
Chopra, S. and Tadi, P. Neuroanatomy, Nucleus Gracilis. 2021 Jul 28. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 31536247. https://pubmed.ncbi.nlm.nih.gov/31536247/
Snell, R.S. (2010). ‘Chapter 4: The Spinal Cord and the Ascending and Descending Tracts, in Clinical Neuroanatomy. (7th ed.) Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, pp. 149-151.
Al-Chalabi, M., Reddy, V. and Alsalman, I. Neuroanatomy, Posterior Column (Dorsal Column). 2021 Jul 31. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan–. PMID: 29939665. https://pubmed.ncbi.nlm.nih.gov/29939665/