Craniometric Indices of Nigeria Skulls

Abstract

Gnathic index is the ratio of basion -prosthion to basion -nasion multiplied by hundred. Gnathic index has been classified into three namely, orthognathous which is 98 and below, mesognathous which ranges between 98-103, prognathous which is above 103. Palatal index is ratio of palatal breadth to palatal length multiplied by hundred and is also classified into three: leptostphylin or narrow palate which is less than 79.9, mesostphylin or medium palate which ranges from 80-84.9 and brachystphylin or broad palate which is 80 and above.Orbital index is ratio of greatest height of the orbital cavity to its greatest breadth multiplied by hundred [22]. Three classes of orbit index have been described: Megaseme (large) with orbital index of 89 and above usually seen in yellow races [5]. Mesoseme (intermediate): The orbital index range between 89 and 83. This type is seen in the white races [24]. Microseme (small): Orbital index 83 or less. This type is characteristic of the black races where the orbital opening is rectangular [5]. Nasal index is ratio of the greatest width of the nasal aperture to the length or height multiplied by hundred [22]. There are three main nasal types; leptorrhine, (narrow) which ranges from 54.9 to 69.9. Mesorrhine