ANATOMY OF THE SKELETON. -OSTEOLOGY. 



OSSEOUS SYSTEM OF THE 

 HORSE. 



In the form of answers to a series of 

 questions, the student will become ac- 

 quainted with the name, location, form, use, 

 and general peculiarities of the various 

 bones composing the horse's skeleton. 



Q. What is understood by the 7iatural 

 skeleton ? — A. The term is applied when 

 the whole bones are held together by their 

 natural attachments : ligaments, cartilages, 

 and synovial membranes. 



Q. Why is the term, artificial, sometimes 

 applied to the skeleton ? — A. Because the 

 bones, having been divested, by maceration 

 or otherwise, of their connecting ligaments, 

 etc., are united artificially.) by wire and 

 plates of metal. 



BONES OF THE CRANIUM. 



Q. Enumerate the cranial bones. — A. 

 Frontal, two parietal, occipital, four tempo- 

 ral, ethmoid, sphenoid : ten. 



FRONTAL BONE (oS FRONTIs). 



Q. Describe the situation of the frontal 

 bone. — A. It occupies the antero-superior 

 part of the cranium in the region known as 

 the forehead. 



Q. What are its peculiarities ? — A. In 

 form it is irregular, having two surfaces 

 and four borders. Its surfaces are flat 

 externally, concave internally. Its internal 

 surface is divided by a septum into anterior 

 and posterior concavities. The posterior 

 one is occupied by a portion of the anterior 

 lobe of the cerebrum ; the anterior consti- 

 tutes the frontal sinuses, they being sepa- 

 rated from each other by the nasal spine. 

 The concavity is further divided into shal- 

 low chambers by imperfect septa. 



Q. Describe the borders of the os frontis. 

 — A. They are denticulated and squamous. 

 The posterior is arched, describing segments 

 of two circles. The anterior or nasal is 

 waving, inclines backwards and outwards. 

 The frontal border is straight, anteriorly 

 broad and triangular. The ethmoidal or 

 outer border is irregular, and unites with 

 the lachrymal, sphenoid, and ethmoid bones. 



PARIETAL BONES (oSSA PARIETALa). 



Supposing the horse to be an adult, we 

 shall consider these bones as one. 



Q. What is the situation of the parietal 

 bone ? — A. It occupies the mesio-superior 

 part of the cranium. 



Q. Describe the same. — A. Its form is 

 quadrilateral : vaulted, concave internally, 

 and convex externally. It has two sur- 

 faces and four borders, denticulated and 

 squamous. 



Q. What is observable on the convex sur- 

 face ? — A. A. longitudinal messian crest, 

 bifurcating anteriorly ; which indicates the 

 location of the sutures, now obliterated by 

 age. Between the bifurcatures arises an 

 eminence above the cranial surface. 



Q. Describe the appearance of the inter- 

 nal surface? — A. It is indented by, and 

 receives, the lobular eminences of the cere- 

 brum, and it is also furrowed by arterial 

 ramifications which supply the dura mater. 



temporal BONES (oSSA TEMPORUm). 



Q. What portion of the cranium do the 

 ossa temporum occupy ? — A. Its sides and 

 base. 



Q. How do these bones differ from those 

 in man ? — A. In man they are divided into 

 three portions, squamous, petrous, mastoid; 

 yet in reality they are united. In the horse 



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