ANATOMY* 



Osteology 



Give the properties and describe the development of the growth of bone. 



Bone is composed of one-third animal matter and two-thirds 

 mineral matter, principally phosphates and carbonates of lime. 



Externally, bones are covered by a very vascular and nervous, 

 fibrous membrane, except over the articular surfaces and insertion 

 of tendons and ligaments. Bone proper consists of lamellae, trav- 

 ersed by "Haversian canals." These canals are very minute and 

 are part of the vascular system. The medulla, or marrow, is a 

 pulpy, fatty substance which fills the interior and the areolae of the 

 spongy tissue of bones. Blood-vessels and nerves enter by way of 

 the nutrient canal. Flat bones (found in the head) do not have a 

 medullary cavity. 



Bones are developed from cartilages and fibrous tissue. The 

 bones of the face and cranium are the only ones formed from the 

 latter. Cartilage, undergoing calcification and being ramified with 

 blood-vessels which carry the osteoblasts (bone-producing cells), 

 eventually becomes hard, dense bone. Fibrous tissue is transformed 

 very much the same except that the blood-vessels and other directing 

 lines do not arrange themselves in parallel as in the long bones 

 and, as a result, the medullary canal is absent, it being replaced 

 by irregular, communicating cavities, called medullary spaces. 



How many bones are there in the skeleton of the horse? 



' The number is subject to slight variation in different skeletons. 

 Considering the sacrum as a single bone, the os hyoides as one and 

 16 as the average number of coccygeal vertebrae, there are 191 

 bones in the horse 's skeleton. 



Name the bones of the cranium. 



Occipital, parietal, frontal, sphenoid and ethmoid, and two tem- 

 poral — seven in all. 

 Name the bones of the head. 



Besides those of the cranium, above mentioned, there are the 

 following pairs : superior maxillary, premaxillary, palatine, ptery- 

 goid, malar, lachrymal, nasal, superior and inferior turbinated, and 

 three single bones — vomer, inferior maxillary and hyoid. 



♦Unless otherwise stated all questions relate to the horse. 



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