Tripartite Os Inca: an embryological and morphological study

ABSTRACT

Inca bone [Os Inca] or os interparietale is an interesting developmental cranial variation. It is the portion of the squamous part of the occipital bone that lies superior to the highest nuchal line when this portion remains separate throughout life. In one hundred and ten human adult skulls examined in this study an Inca bone was found in only one specimen; it was tripartite. In this presentation the embryological background and morphological features of this anomaly are discussed