modern variation and evolutionary change in the hominin eye orbit

inferiorly through deposition on the exocranial side, or the internal orbital roof, andresorption on the endocranial surface just below the frontal lobes (Enlow & Hans, 1996).During this period the malar region is relocating posteriorly through deposition onthe anterior surface and resorption on the posterior, which together with forward anddownward movement of the orbital roof, creates a more obtuse facial angle relative to theFrankfurt Horizontal Plane. This angle is a unique human characteristic to the exclusionof all other mammals (Enlow & Hans, 1996), and is primarily the result ofencephalization and reduced facial prognathism throughout human evolution that occurby way of changes to the pattern of growth and development in the brain, cranial vault,basicranium, and face during this time (Cobb, 2008; Lieberman, McBratney, Krovitz,2002; Bastir et al. 2008).The floor of the orbit is primarily formed by the zygomatic bones that make upthe anterior and lateral portion of the base of this feature, and the maxilla, which is alsothe roof of the maxillary sinus. During ontogeny there is a threefold increase in the areaoccupied by these bones, which primarily occurs in association with the forward anddownward displacement of the nasomaxillary complex by way of maxillary suturalgrowth (Enlow & Hans, 1996). During this anterior and inferior migration of thenasomaxillary complex however, the orbital floor and nasal floor grow away from eachother, which acts to increase facial height while also limiting the amount of net inferiormovement in the floor of the eye orbit.During early childhood the nasal floor is nearly in line with the floor of the eyeorbits, but moves downward during displacement of the nasomaxillary complex until itbecomes substantially separated from the orbital floor in adulthood. In order to maintain13