of the foot and toes are the same in number as those of the hand and
fingers, but they differ greatly in size and form and have less freedom of
motion. The _femur_, which gives form to the thigh, is the longest bone of
the body. The _tibia_, or shin bone, and the _fibula_, the slender bone by
its side, give form to the lower part of the leg (Fig. 102).

The legs are mechanical devices (walking machines) for moving the body
from place to place. The feet serve both as supports for the body and as
levers for pushing the body forward. By their attachment to the legs they
may be placed in all necessary positions for supporting and moving the
body.

The different bone groups are shown in Fig. 97 and named in Table IV.

*Adaptation to Special Needs.*--When any single bone is studied in its
relation to the other members of the group to which it belongs or with
particular reference to its purpose in the body, its adaptation to some
special place or use is at once apparent. Each bone serves some special
purpose, and to this purpose it is adapted by its form and structure. Long
bones, like the humerus and femur, are suited to giving strength, form,
and stiffness to certain parts, while irregular bones, like the vertebrae
and the pelvic bones, are fitted for supporting and protecting organs.
Others, like the wrist and ear bones, make possible a peculiar kind of
motion, and still others, like the ribs, are adapted to more than one
purpose. The vast differences in shape, size, structure, and surface among
the various bones are but the conditions that adapt them to particular
forms of service in the body.

TABLE IV - THE PRINCIPAL BONES AND THEIR GROUPING IN THE BODY

I. AXIAL SKELETON

A. _Skull_, 28.

1. Cranium, 8.

_ a._ Frontal, forehead 1
_ b._ Parietal 2
_ c._ Temporal, temple 2
_ d._ Occipital 1
_ e._ Sphenoid 1
_ f._ Ethmoid 1

2. Face, 14.

_ a._ Inferior maxillary 1
_ b._ Superior maxillary 2
_ c._ Palatine, palate 2
_ d._ Nasal bones 2
_ e._ Vomer 1
_ f._ Inferior turbinated 2
_ g._ Lachrymal 2
_ h._ Malar, cheek bones 2