THE HORSE. 



39 



LACHRYMAL BONES (oSSA LACHRYMALIa). 



There are two lachmyral bones: we shall 

 describe but one, considering that they are 

 both alike, as indeed are those already refer- 

 red to, in a plural sense. 



Q. What is the situation of the lachry- 

 mal bone ? — A. It occupies the antero- 

 external part of the orbit. 



Q. How is it divided ? — A. Into three 

 surfaces and five borders. 



Q. Name the surfaces. — A. Internal, 

 external, and orbital. 



Q. Name the borders. — A. External 

 and internal facial, nasal, and external and 

 internal orbital. 



Q. What is observable in the orbital ex- 

 cavation of this bone ? — A. The lachrymal 

 fossa. 



Q. What occupies this fossa or groove ? — 

 A. The lachrymal vessels, sac, and duct. 



Q. With what bones is it connected ? — 

 A. With the frontal, nasal, malar, and supe- 

 rior maxillary bones. 



palate bones (ossa palati). 



Q. What is the situation of the palate 

 bones ? — A. They are placed in the infe- 

 rior posterior part of the face, adjoining the 

 base of the cranium. 



Q. What does the palatine surface form ? 

 — A. The palatine arch or roof of the 

 mouth. 



Q. What of the nasal surface ? — A. It 

 forms the posterior surface of the nasal 

 outlet. 



Q. What other surfaces do these bones 

 present ? — A. Ethmoidal and orbital. 



Q. To what part of the bone is the vel- 

 lum palatei attached ? — A. To the palatine. 



Q. How are the palate bones united to 

 the superior maxillary? — A. By their supero 

 and infero lateral borders ; each being den- 

 ticulated. 



Q. What other connections have the pal- 

 ate bones? — A. They are joined to the 

 frontal, ethmoid, sphenoid, vomer, and in- 

 ferior turbinated bones. 



turbinated bones (ossa turbinata supe- 



RIORA ET INFERIORa). 



Q. Where are the ossa turbinata located ? 



— A. Within the nasal cavity : the superior 

 above, and the inferior below. 



Q. What is their form, and how are they 

 divided ? — A. In form they are oblong, thin, 

 foliated, convoluted, scroll-like, and cavern- 

 ous. They are divided into external and 

 internal surfaces ; superior and inferior ex- 

 tremities. 



Q. How many bones are there? — A. 

 Four. 



Q. Describe the bones. — A. Their ex- 

 ternal surface is convex, and presents series 

 of longitudinal grooves which mark the 

 ramifications of small blood-vessels. The 

 internal surface is cellular, being unequally 

 divided by transverse septa. Then- interior 

 is capacious ; they are open superiorly and 

 closed anteriorly. They are porous and 

 elastic. The superior bone exceeds in 

 volume the inferior, and makes its convolu- 

 tion from below, its superior border being 

 attached ; whereas, the reverse is the case 

 with the inferior one. 



Q. What are their connections ? — A. 

 The turbinated bone is connected above with 

 the ethmoid ; and laterally, with the nasal 

 bone. 



VOMER. 



Q. From what does the name of this 

 bone arise ? — A. From its resemblance to 

 a ploughshare. 



Q. What are its uses ? — To divide the 

 nasal chambers and permit the expansion 

 of olfactory nerves. 



Q. What is inserted into its superior 

 groove ? — A. The septum narium. 



Q. What are its connections ? — A. It 

 unites with the ethmoid, sphenoid, superior 

 and anterior maxillary, and palate bones. 



lower jaw. INFERIOR MAXILLARY BONE 



(os maxillare inferius). 



Q. What is the situation of this bone ? — 

 A. It composes the inferior and posterior 

 parts of the face. 



Q. What is the foetal state of the bone ? 



— A. In the foetal state it is divided, at its 

 inferior junction, by a connecting cartilage, 

 hence the part has been called its symphysis. 



Q. How is the bone divided ? — A. Into 



