60 THE HUMAN BODY 



vertebra in Fig. 23, consists in the adult of a single bone; but cross- 

 ridges on its ventral surface indicate the limits of the five separate 

 vertebrae of which it is composed in childhood. It is somewhat 

 triangular in form, its base being directed upwards and articulat- 

 ing with the under surface of the body of the fifth lumbar verte- 

 bra. On its sides are large surfaces to which the arch bearing the 

 lower limbs is attached (see Fig. 14). Its ventral surface is con- 

 cave and smooth and presents four pairs of anterior sacral foramina, 

 which communicate with the neural canal. Its dorsal surface, con- 

 vex and roughened, has four similar pairs of posterior sacral foramina. 



The coccyx (Fig. 24) calls for no special description. The four 

 bones which grow together, or ankylose, to form it, represent only 

 the bodies of vertebrae, and even those incompletely. 



Details of the Skull. An account of the bones which make up the 

 skull can conveniently be given in tabular form. Examination of the 

 table will show that all the bones are either single or paired. Single 

 bones are all median, paired bones occupy corresponding positions 

 on each side of the mid-line. Figs. 25 and 26 will enable the reader 

 to gain a fairly good notion of the form and relations of individual 

 bones; for greater detail works on anatomy should be consulted. 

 Cranium: 



1 Frontal, forehead (Fig. 25, F). 



2 Parietal, crown (Fig. 25, Pr). 



1 Occipital, base of skull (Fig. 25, 0). 



2 Temporal, ear region (Fig. 25, T). 



1 Sphenoid, base of cranium and back of orbit (Fig. 25, 



S.) _ 

 1 Ethmoid, between cavities of cranium and nose (Fig. 



25, E). 

 Face: 



1 Inferior maxilla, lower jaw (Fig. 25, Md). 



2 Maxillae, upper jaw, front of hard palate (Fig. 25, MX). 

 2 Palatine, back of hard palate, front of posterior nares 



(Fig. 26, Pi). 

 2 Nasal, bridge of nose (Fig. 25, N). 



1 Vomer, partition between nostrils (Fig. 26, V). 



2 Inferior turbinate, inside nostrils (not shown in Fig.). 

 2 Malar, cheeks (Fig. 25, Z). 



2 Lachrymal, inside wall of orbit (Fig. 25, L). 



