Gracile tubercle

Medically reviewed by Healthline Medical Team on April 14, 2015Published on April 14, 2015

The clava, also known as the gracile tubercle, is located in the medulla oblongata, otherwise known as the lower brainstem. It processes sensations from the lower portion of the body, such as the legs and the pelvis. To be precise, it is responsible for all feelings of touch, heat, pain, and other sensations below the sixth thoracic vertebra, often described as T6. T6 is located just below the armpits. It also allows the brain to process where other body parts are in relation to each other. This is what enables humans to walk while blindfolded.

The neurons within the clava form a bump on the brainstem known as the gracile tubercle. These neurons are second-order neurons that carry information from the clava to the medial lemniscus, a bundle of sensory nerve fibers. Second-order neurons are the second part of the three-part chain that delivers sensory information. The neurons of the clava are part of a group of fibers called the internal arcuate fibers.

From the medial lemniscus, information is then transmitted to the thalamus, which is responsible for all autonomic (unconscious or involuntary) nervous responses. The counterpart of the clava, which controls the upper body's sensations, is the cuneate nucleus.

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