10 THE VETERINARY SCIENCE. 



long bones are divided into a shaft and two extremities. Flat 

 bones are found where vital organs need protection. Example: 

 Shoulder blade and ribs, to protect the heart and lungs; pelvic 

 or hip bones, to protect the bladder, rectum and other urinary 

 and genital organs; also the cranial bones, to protect the vital 

 organ called the brain. Irregular bones are found in the spinal 

 column and in the joints, such as the knee or carpus hock or 

 tarsus, where great strength is required. 



HEAD BONES. 



In speaking of the different points of importance in connec- 

 tion with the head bones of the horse, in making a cross or 

 longitudinal section of the head, you will notice it is full of 

 cavities or sinuses. The uses of these are to lighten the head 

 and also to warm the air as it passes into the nostrils on its 

 road down to the lungs; you will also find it is full of foramen 

 or small holes for the nerves from the brain and various blood 

 vessels to pass through to the organs situated in the head, 

 such as the tongue, lips, and the various glands in and around 

 the head. 



Then we have the cavities in which the eyes are situated, 

 one on each side of the head, called the orbital fossa. In examining 

 this fossa you will find a small opening or foramen, through 

 which the optic nerve passes in coming from the brain to the 

 eye. This is the nerve of sight. Then the most important part 

 of all to consider is the cranial cavity in which that very impor- 

 tant organ is situated called the brain, which controls all the 

 various functions and movements of the body. 



Then we have another point, viz. : the situation of the 



drum of the ear. It is situated in the hardest bone we find 



in the whole skeleton, called the petrosal. The nerve that 



gives the function called hearing comes from the brain down to 



the petrosal bone and enters by a small foramen or hole into 



the drum of the ear to give hearing. This nerve is called the 



auditory nerve. 



CERVICAL OR NECK BONES. 



In considering these bones, we find seven in number. The 

 first and second bones proceeding from the head receive special 

 names. The first one is called the atlas, from which the head 

 is suspended and attached to; it somewhat resembles the body of 

 ■A bird with wings out. The next bone receives the name of 



