[Morphological studies on the margo infraorbitalis (on the longitudinal changes of infraorbital suture)]

The purpose of this study was to obtain information on the developmental changes of the infraorbital margin and the form of infraorbital suture. 136 Indian craniums were divided into five developmental groups according to the stage of eruption of the teeth. The anterior view of the skull was observed photographically. The results are summarized as follows: 1. The infraorbital margins were divided into three types according to the shape of the infraorbital suture. Type I: Infraorbital suture was independent. Type II: Infraorbital suture and zygomatico-facial suture coincided. Type III: Infraorbital suture and zygomatico-facial suture were joined. Type I was the basic type of infraorbital suture. 2. The frequency of type I was 90% at the pre-eruption stage, 31.8% at the eruption stage, 41.7% at the deciduous dentition stage, 56.3% at the mixed dentition stage, and 62% at the permanent dentition stage. 3. On the distance between the median line and each point of the infraorbital margin the growth rate is expressed in values relative to a standard that was based on the pre-eruption stage. The growth rate was greatest at the highest point of the superior margin in the infraorbital foramen (1.79 times), the middle rate was at the position of the infraorbital suture (1.72 times) and the smallest rate was 1.63 times at the position of the zygomatico-facial suture. Each measuring point moved towards lateral side.