Craniofacial development in rats with early resection of the zygomatic arch.

Eighty-two-day-old male Wistar rats were selected to study the pattern of craniofacial growth following resection of the zygomatic arches. Rats were divided into three groups: group I (n = 14), the control group; group II (n = 15), with unilateral resection of the zygomatic arch; and group III (n = 8), with bilateral resection. Direct dry skull and cephalometric measurements show increased facial projection and decreased transverse facial width on the side of the resected arch. If the results are extrapolated to the growth pattern of patients with the Treacher Collins syndrome, we can conclude that the zygomatic arch acts as a "moderator" in the morphologic development of the face.