22 



Bones of the Skull. 



Os frontale 



Crista galli 



Lamina perpendicularis 



Os iiasale 



Lamina cribrosa (in section) 



Corpus ossis sphenoidalis 



Concha nasalis 

 inferior 



Lamina medialis processus 

 pterygoidei ossis sphenoidalis 



Vomer 



i 

 i 



Processus palatinus maxillae 



25. Ethmoid bone, os ethmoidale, lamina perpendicularis, 



from the left. 



The lamina perpendicularis or perpendicular plate (see also Figs. 21, 65, 66 and 75) 

 is quadrangular with unequal sides; at its upper border in the median plane it is in large 

 part united to the inferior surface of the lamina cribrosa; it hangs down perpendicularly and 

 free between the two labyrinths and thus forms a part of the bony nasal septum. At its 

 upper margin it presents small grooves which are continuations of the medial foramina of the 

 lamina cribrosa. The upper border is attached in front to the posterior surface of the spina 

 frontalis oss. frontalis (sutura frontoethmoidalis); the posterior margin unites with the crista 

 sphenoidalis oss. sphenoidalis (sutura sphenoethmoidalis) , the inferior with the anterior margin 

 of the vomer, the anterior with the cartilaginous nasal septum. 



Deviations of the lamina perpendicularis as a whole or in single spots from the median 

 plane are very frequent. 



