36 



HITCHCOCK'S ANATOMY 



lar. The long ones are mostly found in the extremities, and 

 consist of a hollow shaft with enlarged and partially smoothed 

 extremities, and sometimes a rough or elevated portion along 

 their central portions. Those which belong to this class, are 

 the Clavicle, Humerus, Radius, Ulna, Femur, Tibia, Meta- 

 tarsus, and Metacarpus, Phalanges and Ribs. 



93. Short Bones, — The Short bones are irregularly cuboid 

 in form, and are found in those places where there is but 

 little motion of the part. They are the Vertebrae, Coccyx, 

 Carpus and Tarsus, Patella, and Sesamoid bones. 



94. Flat Bones. — The Flat bones are arranged to enclose 

 and protect cavities. Those of the head are made of two 

 layers of bony matter, w T ith an intervening porous substance 

 called the Diploe. These are the Occipital, Parietal, Frontal, 

 Nasal, Lachrymal, Vomer, Sternum, Scapula, and the Os 

 Innominatum. 



95. Irregular Bones. — The Irregular bones are those 

 which belong to neither of the preceding classes, and have 

 no typical form. They are the Temporal, Sphenoid, Eth- 

 moid, Superior and Inferior Maxillary, Palate, Turbinated, 

 Hyoid, and Sacrum. 



96. Development of Bone from Cartilage. — The early 

 condition of bone is that of cartilage, which has the general 

 outline of the bone, and from the subsequent process may 

 be called the mould of the bone. Very early in life, and 

 even before birth, bony matter begins to be deposited in the 

 cells of the matrix (cartilage) until at length, the whole 

 becomes solid, as it is found in adults. At birth the only 

 bone which is completely ossified is that portion of the tem- 

 poral called the petrous, which contains the organ of hear- 

 ing, while all the bones are not completely ossified be- 

 fore the 12th year of life. This process of hardening, or os- 



93. What is the general outline of short bones and where are they found ? Give ex- 

 amples. 94. Give the use of the flat bones. Examples also. 95. What are some of 

 the irregular bones? 96. What is the first stage of bone? When is the process of ossifi- 

 cation complete ? W r hat bones are the first that become ossified? 



