An oblique expanding fusion cage device including a body with a superior portion and an inferior portion. The superior portion and the inferior portion have a proximal end and a distal end. The fusion cage device also includes a pathway, an opening, and an expanding member. The pathway travels from the proximal end to the distal end of the device between the superior and inferior portions. The opening in the proximal end of the body enables access to the pathway. The expanding member may be removably inserted into the opening and is moveable toward the distal end of the body, wherein the expanding member engages the superior portion and the inferior portion as the expanding member moves distally within the pathway.