OSSA SPONGIOSA INFERIORA. THE VOMER. 95 



the pterygoid processes of the os sphenoides ; by the transverse 

 ridges of their nasal lamellae to the ossa turbinata inferiora, and 

 by the spines of the square bones to the vomer. *j 



j/n 



The Ossa Spongiosa, or Turbinata Inferiora. 



The ossa spongiosa, or turbinata inferiora, are so named to 

 distinguish them from the upper spongy bones, which belong 

 to the os ethmoides ; but these lower spongy bones are quite 

 distinct, and connected in a very slight way with the upper 

 jaw bones. They are rolled or convoluted, very spongy, and 

 exceedingly light. Each of them is attached to the os maxil- 

 lare superius, near the transverse ridge, by a hook-like process, 

 and covers a part of the opening of the maxillary sinus. One 

 end is turned towards the anterior opening of the nose, and 

 covers the end of the lachrymal duct ; the other end of the same 

 bone points backwards towards the throat. The curling plate 

 hangs down into the cavity of the nostril, with its convex side 

 towards the septum. This spongy bone differs from the spongy 

 processes of the ethmoid bone, in being less turbinated or 

 complex, and in having no cells connected with it. 



The Vomer. 



The vomer is a thin flat bone, which forms the back part of 

 the septum of the nose. Its posterior edge extends downwards 

 from the body of the os sphenoides to the palatine processes of 

 the ossa palati, separating the posterior nares from each other. 



The figure of this bone is an irregular rhomboid. Its sides 

 are smooth ; and its posterior edge appears in an oblique 

 direction at the back part of the nostrils. The upper edge is 

 firmly united to the base of the sphenoid bone, and to the nasal 

 plate of the ethmoid. It is hollow for receiving the processus 

 azygos of the sphenoid, and where it is articulated to the nasal 

 plate of the ethmoid, it is composed of two lamina which 

 receive this plate between them. The anterior edge has a 

 long furrow in it, where the middle cartilage of the nose enters. 

 The lower edge is firmly united to the nasal spines of the 

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