Zygomatic process

Abstract: Three-dimensional osseous surface re-formation imaging from CT scans was used to examine the facial skeletons of 14 living patients with mandibulofacial dysostosis. Partial to complete aplasia of the zygomatic process of the temporal bone, mild hypoplasia to aplasia of the frontal process of the zygoma, antimongoloid slant of the transverse orbital axis, and hypoplasia of the medial pterygoid plates and muscles are common to all patients examined. Deformities of the zygoma, zygomatic process of the frontal bone, mandible, and lateral pterygoid plates and muscles vary from minimal to severe, including aplasia. The body of the zygoma is the least affected part of the bone. Right-left asymmetry characterizes these deformities in all patients. The most consistent skeletal aplasia (cleft) in mandibulofacial dysostosis involves the zygomatic process of the temporal bone rather than the zygoma itself.

Abstract: Cutmarks inflicted by a stone tool were observed on the right maxilla of Stw 53, an early hominid partial skull from Sterkfontein “Member 5” (South Africa). The morphology of the marks, their anatomical placement, and the lack of random striae on the specimen all support an interpretation of this linear damage as cutmarks. The location of the marks on the lateral aspect of the zygomatic process of the maxilla is consistent with that expected from slicing through the masseter muscle, presumably to remove the mandible from the cranium. Although radioisotopic dates are not available and relative faunal dating of the deposit from which Stw 53 derives is problematic, the morphology of the hominid skull suggests a Plio-Pleistocene age for the specimen. This therefore constitutes the earliest unambiguous evidence that hominids disarticulated the remains of one another. Am J Phys Anthropol 111:579–584, 2000. © 2000 Wiley-Liss, Inc.

Abstract: Two well-preserved specimens of a “cetothere” from the Lower Miocene Awa and Mizunami Groups, Japan, are described as Isanacetus laticephalus, gen. et sp. nov. It is distinguished by the following combination of characters: fossa for the stapedial muscle elongated anteroposteriorly, with a fully ossified floor; anteroposteriorly broad supraorbital process of frontal, with the orbital margin concave in dorsal view; posterior thrust of the medial rostral elements reaches the level of the center of the orbit; apex of the occipital shield reaches beyond the level of the anterior end of the zygomatic process of the squamosal; nasal slender, elongate, and partly located anterior to level of the preorbital angle of the supraorbital process of the frontal; and zygomatic process of the squamosal slender, elongate, and directed forward and slightly outward. A parsimony analysis of 16 cetaceans and 77 characters failed to identify any synapomorphies for the “Cetotheriidae.” The analysis supports the followi...