basilar(a = adj.pert) basilary - of or relating to or located at the base; "the basilar membrane of the cochlea"
Derived form noun base₄

1.  Relating to, or situated at, the base. [1913 Webster]

2.  Lower; inferior; applied to impulses or springs of action. H. W. Beecher. [1913 Webster]

basilar, adj. of or at the base (esp. of the skull).

Etymology:
mod.L basilaris (as BASIS)

basilar artery, basilar membrane