Lateral pontomesencephalic membrane

The lateral pontomesencephalic membrane separates the ambient cistern form the cerebellopontine cistern.

Insertions: from the pontomesencephalic sulcus, sharing insertion with the Ill nerve cuff and the mescencephalic liliequist - going laterally - reaches the superior aspect of the cerebellar lobule and some transtentorial trabeculae up to the uncus and parahipocampus

Main relations: bridges the space between the brainstem and the cerebellar surface conforming the division between the crural-ambiens from the cerebello pontine cisterns