Vol. 8, Issue 9 (2019)

Author(s):
Rajalakshmi K, Sridevi P and SivaKumar M

Abstract:
Neurocranium was composed of the unpaired occipital, sphenoid and paired parietal, frontal and temporal. The occipital bone was composed of three parts, squamous part (Supraoccipital), lateral or exoccipital and basal part (Basioccipital) all of which contributed in the formation of foramen magnum. From the floor of the foramen magnum, the hemispherical single occipital condyle projected ventrally. The supra occipital presented a median external occipital protuberance from which a median occipital crest extended upwards and joined the nuchal crest. Sphenoid formed the major part of the floor of the cranial cavity with basi-phenoid caudally and pre-sphenoid rostrally. The orbital wings of presphenoid also contributed to the formation of the inter-orbital septum. The parietal was located in between the frontal and supra-occipital bones. The frontal bone was the largest of all cranial bones and formed the highest point of skull. The orbital plates of the frontal formed the medial wall of the orbit and were fused medially with each other and formed the inter-orbital septum. The temporal bone formed the lateral wall of the cranial cavity and consisted of two parts, namely squamous temporal and ear capsule (os-oticum). The orbital wings of pre-sphenoid and orbital plates of frontal bones of either sides were connected medially and formed the inter-orbital septum. The caudal part of the perpendicular plate of ethmoid also joined the inter-orbital septum.