68 OSTEOLOGY. 
The table represents the number of bones distinct and separable during adult 
life: 
Single Bones. Pairs. Total. 
The vertebral column : 26 re 26 
The skull : ; 6 8 Me 
Axial skeleton - The sternum : ; ] i it 
The ribs. ; F Nn 12 94 
The hyoid bone — . : 1 ae Il 
: The upper limbs”. : Pe 32 64 
Appendiowtar aketeton {Te-UP! 
epee neue ekeleton (The lower limbs. : en ol 62 
The ossicles of the ear : ; j , sont 3 6 
o4 86 206 
Bones are often classified according to their shape. Thus long bones, that 
is to say, bones of elongated cylindrical form, are more or less characteristic of 
the limbs. Broad or flat bones are plate-like, and serve as protective coverings to 
the structures they overlie: the bones of the cranial vault display this particular 
form. Other bones, such as the carpus and tarsus, are termed short bones; whilst 
the bones of the cranial base, the face, and the vertebree, are frequently referred to 
as irregular bones. 
Various descriptive terms are applied to the prominences commonly met with 
on a bone, such as tuberosity, eminence, protuberance, process, tubercle, spine, 
ridge, crest, and line. ‘These may be articular in their nature, or may serve as 
points or lines of muscular and ligamentous attachment. The surface of the bone 
may be excavated into pits, depressions, fossee, cavities, furrows, grooves, and 
notches. These may be articular or non-articular, the latter serving for the recep- 
tion of organs, tendons, ligaments, vessels, and nerves. In some instances the 
substance of the bone is hollowed out to form an air space, sinus, or antrum. 
Bones are traversed by foramina and canals; these may be for the entrance and exit 
of nutrient vessels, or for the transmission of vessels and nerves from one region to 
another. A cleft, hiatus, or fissure serves the same purpose. Channels of this kind 
are usually placed in the line of a suture, or correspond to the line of fusion of the 
primitive portions of the bone which they pierce. 
Composition of Bone.—Bone is composed of a combination of organic and 
inorganic substances in about the proportion of one to two. 
Organic matter (Fat Collagen) . : ; : 31-04 
Mineral matter 
Calcic phosphate . ; : : 58-2: 
Calcic carbonate (ay) 
Calcic fluoride : 1-414 68-97 
Magnesie phosphate : : , 1-32 | 
Sodie chloride : . 4 : 69 |) ; 
100-00 
The animal matter may be removed by boiling or charring. According to the 
completeness with which the fibrous elements have been withdrawn, so the brittle- 
ness of the bone increases. When subjected to high temperatures the earthy 
matter alone remains. By soaking a bone in acid the salts may be dissolved out, 
leaving only the organic part. The shape of the bone is still retained, though it 
has now become soft, and can be bent about in any direction. 
Bone may be examined either in the fresh or dry condition. In the former 
state it retains all its organic parts, which include the fibrous tissue in and around 
it, the blood-vessels aiid! their contents, together with the cellular elements found 
within the substance of the bone itself, and the marrow which occupies the lacunar 
spaces and marrow cavity. In the dried or macerated bone most of these have 
disappeared, though a considerable portion of the organic matter still remains, 
even in bones of “great antiquity and in a more or less fossil condition. Con- 
sidering its nature and the amount of material employed, bone possesses a remark- 
