An assembly for facilitating brain surgery performed through an opening having a rim, created in the skull of a patient and having a curved frame, defining an inward dimension and an outward dimension. Also, at least one clamp arm subassembly is attached to the frame, and has a clamp arm frame clamp, releasably attached to the frame； a clamp arm having a longitudinal dimension, releasably held and supported by the clamp arm frame clamp, and adjustable relative to the frame clamp along the longitudinal dimension； and a skull clamp, supported by the arm, and adapted to clamp onto the rim. Further included is at least one spatula arm subassembly, which has a spatula arm frame clamp, releasably attached to the frame； a spatula arm held and supported by the spatula arm frame clamp； and a spatula extending from the inward end of the spatula arm of the spatula arm subassembly.
