Internal arcuate fibers
In neuroanatomy, the internal arcuate fibers or internal arcuate tract are the axons of second-order sensory neurons that compose the gracile and cuneate nuclei of the medulla oblongata.These second-order neurons begin in the gracile and cuneate nuclei in the medulla.They receive input from first-order sensory neurons, which provide sensation to many areas of the body and have cell bodies in the dorsal root ganglia of the dorsal root of the spinal nerves.The internal arcuate fibers are part of the second-order neurons of the posterior column-medial lemniscus system, and are important for relaying the sensation of fine touch and proprioception to the thalamus and ultimately to the cerebral cortex.2° (Spinomesencephalic tract → Superior colliculus of Midbrain tectum)