in.] THE CRANIAL SKELETON. 77 



special bony sockets to which the name alveoli has been 

 applied. 



When the skull is viewed in profile the sharp bony projec- 

 tion of the nose is seen in front and the round prominence 

 of the occiput behind, while from the malar prominence the 



zygoma extends backwards to above the mastoid process 



enclosing a fossa (in which is placed a muscle called the 

 " temporal ") and having beneath its hinder end a noticeable 

 aperture which is the external bony opening of the ear. A 

 ridge also runs upwards from the malar prominence and 

 forms the external margin of the bony orbit. 



The skull is said to be divided into certain regions. Thus 

 \ve have the base or basilar region, and opposite to it the 

 vertex, sinciput, or sincipital region ; we have the region 

 of the forehead or frontal region, and opposite to it that of 

 the back of the head or the occipital region. 



At the side of the head we have posteriorly and above, the 

 parietal* 1 - region ; beneath this and within the arch of the 

 zygoma, the temporal region (to which is attached the tem- 

 poral muscle before referred to), separated from the orbital 

 region by the outer, hinder bony wall of the orbit. 



The skull is made up of different bones of very different 

 sizes and shapes. When it is looked at from above, a trans- 

 verse zigzag line of union is seen to run across behind the 

 forehead. This is called the coronal suture. 2 



Running directly backward from this, for some distance 

 along the middle line of the vertex, is another suture, termed 

 sagittal, and it ends behind by joining a wide V-shaped 

 suture with the apex upwards, which is called lambdoidal. 3 



Turning now to the lower jaw, this when attached to the 

 skull is seen to fit, by a rounded head/ into a shallow cavity 

 placed on each side in front of the external auditory opening, 

 and termed the glenoid 4 surface. 



The number of bones forming the skull decreases, with 

 age, by anchylosis. In its mature condition the skull of man 

 consists of the following bones, which it will be well to notice 

 separately : 



2. The OCCIPITAL bone is of course that of the occiput, and 

 it surrounds the great occipital foramen (or foramen mag- 

 num}. Naturally (when the bones of the skull are separated 



1 From paries, a wall. 



2 Because it is somewhere near the part where a crown or garland would be 

 placed. 3 From its being like the Greek letter X. 



* From T/\;KJ, a socket. 



