It is important to realize that through anatomical variation it is common for the skeleton to have many extra bones ( sutural bones in the skull, cervical ribs, lumbar ribs and even extra lumbar vertebrae ).
2.
At the angle of junction of the sphenoidal and maxillary portions, a short, concave, non-articular part is generally seen; this forms the anterior boundary of the inferior orbital fissure : occasionally, this non-articular part is absent, the fissure then being completed by the junction of the maxilla and sphenoid, or by the interposition of a small sutural bone in the angular interval between them.