An interbody spacer for the spine is provided. The interbody spacer includes a cage and at least one bone screw configured to anchor the cage between two vertebrae of the spine. The cage includes a lock rotationally movable with respect to the cage between a locked configuration and an unlocked configuration. When in an unlocked configuration, bone screws may be inserted and removed from the cage. When in a locked configuration, the insertion and removal pathway of the bone screw is blocked by the lock, thereby, providing backout protection for the bone screws. The lock is coupled to the cage by a pronged retainer and includes a camming surface to provide for incremental rotation of the lock. The lock includes a space-saving shape providing for maximum bone screw angulation on a laterally smaller anterior platform.
