MIDFACIAL RETRUSION IN ADULT BRACHYRRHINE MICE

The purpose of this study was to determine quantitatively whether the Br mouse displays craniofacial size and shape patterns indicative of m idfacial retrusion. Fifteen craniometric variables derived from a tota l of 40 male and female Br mice were compared with an equivalent numbe r of C3H/HeJ adult mice displaying normal murine craniofacial morpholo gy. Univariate statistical analysis showed that Br crania were signifi cantly smaller for all measurements as compared with the C3H/HeJ speci mens. Multivariate analysis revealed that the pattern of measurement c ovariation differed significantly between the two samples. Results ind icated that the midface was significantly shorter in length relative t o the calvaria in mutant mice as compared with C3H/HeJ mice. Therefore , the sagittal midfacial growth trajectory is deficient in Br mice.