Right Occipital Bi-Transtentorial/Falcine Approach. A, The occipital transtentorial approach has been completed, followed by an additional incision of the falx parallel to and 1 cm above the straight sinus. B, The division of the falx provides exposure of the posterior temporomedial structures. C, The contralateral tentorium has been sectioned parallel to the straight sinus, to expose the lateral part of the contralateral half of the quadrigeminal cistern. D, 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. (Images courtesy of AL Rhoton, Jr.)