| Medial lemniscus | |
| Latin: | lemniscus medialis |
In neuroanatomy, the medial lemniscus (also known as Reil's band or Reil's ribbon (for German anatomist Johann Christian Reil) is a large ascending bundle of heavily myelinated decussating (crossing-over) second-order axons that extends throughout the brainstem. It represents the decussation of the internal arcuate fibers (which originate in the nucleus gracilis and nucleus cuneatus). The medial lemniscus is part of the dorsal column–medial lemniscus pathway that conveys information from skin mechanoreceptors to the thalamus.[1] Lesion of the medial lemnisci cause impairment of vibratory and touch sensation.
In the medulla oblongata, axons conveying stimuli from the lower body are situated ventrally/anteriorly, and those of the upper body dorsally/posteriorly. Passing through the pons and midbrain, the axons of the lemniscus rotate laterally by 90° so that those of the upper body come to be situated medially, and those of the lower body laterally.
In the midbrain, it is situated dorsal/posterior to the substantia nigra, and medial to either red nucleus.[2]
It terminates by synapsing with third-order neurons in the ventral posterolateral nucleus of thalamus.