Right Occipital Bi-Transtentorial/Falcine Approach. E, The straight sinus has been displaced to the right to expose the lateral part of the contralateral half of the quadrigeminal cistern. The quadrigeminal plate, trochlear nerve, internal occipital, basal, and internal cerebral veins, P3 segment, and SCA on the contralateral side can be observed. The exposure is better than can be achieved with the occipital transtentorial approach. (Image courtesy of AL Rhoton, Jr.)