Orientation jaw relations are those orient the mandible to the cranium in such a way, that, when the mandible is kept in its most anterior and superior position, the mandible can rotate in sagittal plane around an imaginary transverse axis passing through or near the condyles. It demonstrates the relationship between the jaws & axis of movement. Heartwell defines hinge axis as an imaginary line around which the condyles can rotate without translation. The opening axis is an imaginary line around