Fiber dissection of the ventral pons and medulla, ventral view. Once the CST reaches the pons, it runs between the pontine nuclei and the transverse fibers of the middle cerebellar peduncle (MCP), which has been transected here to  show this relationship. At the pons, the MCP fibers divide into multiple groups travelling anterior, posterior, and through the fibers of the CST. The nerve entry zone of the trigeminal nerve lies postero-lateral in the pons, which makes it less accessible through a purely ventral approach. Within the pyramids, the CSTs are smaller, and more compact, more anterior and more medial. Laterally, the multiple rootlets of CN XII at the pre-olivary sulcus demarcate the lateral limit of the CST. (Image courtesy of JC Fernandez-Miranda)