THE CRANIUM
The cranium is a large and hollow bony case formed by fusion of different bones by zigzag edges it accommodates the brain and its meninges cerebral vessels and origin of cranial nerves which is contained in its spaces the cranium consists of eight bones one occipital two parietals one frontal two temporals one sphenoid and one ethmoid they are joined together by means of irregular and saw like edges called sutures
the occipital bone
the occipital bone forms the back and a part of the base of the skull its lower part contains a large circular opening known as foramen magnum through which spinal cord continues downward the upper edge of the occipital bone is joined with the parietal bones parietal bones form the side walls and also the greater part of the roof of the cranium they are of quadrilateral shape the frontal bone is in the front central portion of the cranium it is joined with two parietal bones it is extended upto the forehead and forms the roof of the orbital and nasal cavities these are two cavities known as frontal sinuses in the frontal bone sagittal suture separates two parietal bones coronal suture separates frontal bone from parietal bone lambdoid suture separates parietal bone from occipital bone
skull also consists the orbits which lodges eye balls in it the roof of the orbits is formed by the frontal bone the lateral wall of the orbit is formed by the zygomatic bone and the great wing of the sphenoid bone several bones like lacrimal bone ethmoid sphenoid and maxilla form the medial wall the floor of the orbit is formed mainly by the maxilla
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