A spinal implant for insertion between adjacent vertebrae for promoting fusion of the vertebrae is a wedge shaped body with upper and lower plates separated by pyramidal sides with one large end and one small end enclosing the body. The upper and lower plates have elongated openings oriented perpendicularly to each other to form an internal labyrinth. The upper and lower openings are to be filled with thin layers of bone graft material to promote rapid ingrowth of living tissue.