Medial Lemniscus - Location of The Medial Lemniscus Through The Brainstem

Location of The Medial Lemniscus Through The Brainstem

• The cuneate and gracile nuclei reside at the closed (lower) medulla, so the lemniscus isn't formed at this level. Fibres from these nuclei will pass to the contralateral side of the brainstem, as the internal arcuate fibres.
• At the open medulla (further up the brainstem), the medial lemniscus contains axons from the trigeminal nerve (which supplies the head region), as well as the arms and legs. It sits very close to the midline, at the same orientation of the midline, with head fibres more dorsal (closer to the back), towards the fourth ventricle.
• By mid-pons, the medial lemniscus has rotated. Fibres from the head are medial, fibres from the leg are lateral.
• The orientation in the midbrain is similar to that in the pons.