Skull and Hyoid 



223 



Again, look at the Eustachian opening : it is situated just internal to the position 

 of the spine, and the tube passes downwards, forwards and inwards from it, and is 

 thus only separated by the Tensor palati from the structures passing through the 

 foramina in the great wing. 



The temporal surface articulates by its front edge (Fig. 183) with the malar and is 

 therefore concave from behind forwards as it enters into the formation of the front 

 wall of the temporal fossa as well as its floor. It is covered by and gives origin to the 

 Temporal muscle. Its margin articulates with the malar in front, above this the frontal, 

 the parietal along the top and the squama behind. 



The orbital or front surface of the wing, nearly flat, and deepening as it is followed 

 out, forms a great part of the outer or postero-external wall of the orbit, and is in 

 relation with the external Rectus (which gains a small additional origin from its inner 

 part) and the lachrymal vessels and nerve. Its upper and inner border is the lower 



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FIG. 183. Sphenoid and left sphenoidal turbinal from the front. 



margin of the sphenoidal fissure and articulates with the frontal outside this ; 

 its outer border is practically the front border of the temporal surface (Fig. 183) and 

 carries the malar, while its lower border is separated from the maxilla by an interval, 

 the sphcno-maxillary fissure, of which it therefore forms the upper and posterior margin. 

 On the bone this lower border separates the orbital surface from a district of variable 

 size that really belongs to the basal area but is cut off from the pterygoid or true 

 basal region by the pterygoid ridge : this district is spheno-maxillary and will be 

 considered with the pterygoid processes. 



The small wing or orbito-sphenoid projects outwards and a little forwards from the 

 body. It has a smooth upper surface that is covered by dura mater and forms part 

 of the anterior fossa ; a smooth rounded and concave posterior edge, to which dura 

 mater is attached after it has covered the back of the sphenoidal fissure and which 

 marks the position of the Sylvian fissure, and along which the spheno-parietal venous 



