78 OS ETHMOIDES. 



with the cribriform plate. They have been described very 

 differently by different authors, some considering them as 

 belonging to the os ethmoides, and others to the sphenoid bone. 

 To the perfect ethmoid bone there are attached two triangular 

 pyramids, in place of the triangular bones ; these pyramids are 

 hollow, the azygos process of the os sphenoides is received 

 between them ; one side of each pyramid applies to each side 

 of the azygos process, another side applies to the anterior 

 surface of the body of the sphenoid bone, in place of the ossa 

 triangularia, and the third side is the upper part of one of the 

 posterior nares.* There are two apertures in each of these 



* This may be considered as an original observation of the lamented Wistar. 

 The merit of it has been denied to him, more particularly by the anatomists of 

 Paris, under an impression that he had been anticipated in it by Bertin, who 

 has written an excellent and minute treatise on osteology. The extent to which 

 the claims of other anatomists interfere with his, he was fully aware of- and it 

 will be seen by the following communications to the American Philosophical 

 Society, that these are placed in as important a light as they deserve af the 

 same time that he vindicates his own pretensions, to have first observed the 

 "cornets sphenoidaux " In the form of triangular hollow pyramids as consti- 

 tuting part of the perfect ethmoid bone. — h. 



Observations on those Processes of the Ethmoid Bone which originally form the. Sphe- 

 noid Sirmses. By C. Wistar, M. D., President of the Society, Professor of 

 Anatomy in the University of Pennsylvania. — Bead, Nov. 4, 1814. 

 It has been long believed that the sinuses, or cavities in the body of the os 

 sphenoides, were exclusively formed by that bone, when Winslow suggested 

 that a small portion of the orbitar processes of the ossa palati contributed to 

 their formation.* 



Many year's after "Winslow's publication. Monsieur Bertin described two 

 bones which form the anterior sides of these sinuses, and contain the foramina 

 by which they communicate with the nose.f 



These bones he denominates "Cornets Sphenoidaux,'' and states that they 

 are most perfect and distinct between the ages of four years and twenty ; that 

 they are not completely formed before this period, and that after it they appear 

 like a part of the sphenoidal bone. — According to his account they are lamina of 

 a triangular form, and are originally in contact with the anterior and inferior 

 surface of the body of the os sphenoides, so that they form a portion of the sur- 

 face of the cavity of the nose. — He believed, that as they increase in size, they 

 become convex and concave, and present their concave surfaces to the body of 

 the sphenoidal bone, which also becomes concave, and presents its concavity to 

 those bones; thus forming the sinuses. 



* In his description of the Ossa Falati, printed in the Memoirs of the Academy of 

 Sciences for 1720. 



t See Memoirs of the Academy ofSciences for 1774. 



