26 BONES or THE HEAD. 



rough for articulating with the cuneiform process of the occipital 

 bone. 



The small wings^ are placed in front of the large. They are 

 triangular, flat, and narrow. Their posterior extremities constitute 

 the anterior clinoid processes, which are perforated by the optic fora- 

 mina^* through which pass the optic nerve and ophthalmic artery. 

 They articulate in front with the frontal bone. 



The great wings are separated from the small by the sphenoidal fis- 

 sure ox foramen^'' which transmits the third, fourth, first branch of the 

 fifth, and the sixth nerves. 



This wing has three surfaces. The cerebral is concave and has 

 numerous depressions for the convolutions of the middle lobe of the 

 cerebrum which lodge in this concavity. It has three foramina. 

 The foramen rotiindum^ transmits the second branch of the fifth pair. 

 Behind it, is the foramen ovale,^ through which passes the third 

 branch of the fifth pair. The posterior angle of this surface is the 

 spinous process, which is perforated by the foramen spinale^^^ by 

 which the middle artery of the dura mater enters the cranium. Pro- 

 jecting from the inferior surface of this process is another called sty- 

 loid,^^ which gives origin to muscles. 



The external surface is the temporal, which is divided by a ridge, 

 and has a process in front ; it is covered by the temporal and external 

 pterygoid muscles. The anterior surface is called the orbital, form- 

 ing a large portion of the orbit of the eye. On the superior surface is a 

 large, triangular, serrated surface, for articulating with the frontal 

 bone ; laterally it articulates with the temporal. 



Pterygoid processes. — These project downwards on either side, 

 and articulate with the palate bones in front. Posteriorly, there is a 

 fossa called pterygoid, which terminates in a notch, and divides the 

 process into an external and internal plate. The external^^ is the 

 broader, and gives origin to the external pterygoid muscle ; the inter- 

 nal'^ is the longer, and terminates in a hook-like process, called the 

 hamulus, over which plays the tendon of the circumflexus palati 

 muscle. The internal plate gives origin to the internal pterygoid 

 muscle, which occupies a portion of the fossa. 



The base of the pterygoid process has a groove upon it, showing the 

 course and connexion of the cartilaginous portion of the Eustachian 

 tube. The 'pterygoid foramen^* perforates the base of the process, 

 and transmits the vidian or recurrent nerve. 



TEMPORAL BONES. 



These are placed on either side of the cranium below the parietal 

 bone. They consist of three portions, squamous, petrous, and mastoid. 



The squamous'^ is thin and shell-like. The external surface is 

 slightly convex, has grooves for the deep temporal artery, and is 

 covered by the temporal muscle. Projecting from the lower part of 



