60 BASE OF THE SKULL. 



is the zygomatic fossa. Behind the nasal fossae, in the middle line, 

 is the under surface of the body of the sphenoid, and the basilar 

 process of the occipital bone, and still further back, the foramen 

 magnum. At the base of the external pterygoid plate, on each 

 side, is the foramen ovale, and behind this the foramen spinosum, 

 with the prominent spine which gives attachment to the internal 

 lateral ligament of the lower jaw and the laxator tympani muscle. 

 Running outwards from the apex of the spinous process of the 

 sphenoid bone, is the fissura Glaseri, which crosses the glenoid 

 fossa transversely, and divides it into an anterior smooth surface, 

 bounded by the eminentia articularis, for the condyle of the lower 

 jaw, and a posterior rough surface for a part of the parotid gland. 

 Behind the foramen ovale and spinosum, is the irregular fissure 

 between the spinous process of the sphenoid bone and the petrous 

 portion of the temporal, the foramen lacerum basis cranii, which 

 lodges the internal carotid artery and Eustachian tube, and in 

 which the carotid branch of the Vidian nerve joins the carotid 

 plexus. Following the direction of this fissure outwards is the 

 foramen for the Eustachian tube, and that for the tensor tympani 

 muscle, separated from each other by the processus cochleariformis. 

 Behind the fissure is the pointed process of the petrous bone which 

 gives origin to the levator palati muscle, and, externally to this pro- 

 cess, the carotid foramen for the transmission of the internal carotid 

 artery and the ascending branch of the superior cervical ganglion 

 of the sympathetic ; and behind the carotid foramen, the foramen 

 lacerum posterius and jugular fossa. Externally, and somewhat in 

 front of the latter, is the styloid process, and at its base the vaginal 

 process. Behind and at the root of the styloid process is the stylo- 

 mastoid foramen, for the facial nerve and stylo-mastoid artery, and 

 further outwards the mastoid process. Upon the inner side of the 

 root of the mastoid process is the digastric fossa ; and a little far- 

 ther internally, the occipital groove. On either side of the fora- 

 men magnum, and near to its anterior circumference, are the con- 

 dyles of the occipital bone. In front of each condyle, and piercing 

 its base, is the anterior condyloid foramen, and directly behind the 

 condyle the irregular fossa in which the posterior condyloid foramen 

 is situated. Behind the foramen magnum are the two curved lines 

 of the occipital bone, the spine, and protuberance, with the rough 

 surfaces for the attachment of muscles. 



The Face is somewhat oval in contour, irregular in surface, and 

 excavated for the reception of two principal organs of sense, the 

 eye and the nose. It is formed by part of the frontal bone and by 

 the bones of the face. Superiorly it is bounded by the frontal 

 eminences ; beneath these are the superciliary ridges, converging 

 towards the nasal tuberosity ; beneath the superciliary ridges are 

 the supra-orbital ridges, terminating externally in the external 

 border of the orbit, and internally in the internal border, and pre- 

 senting towards their inner third the supra-orbital notch, for the 

 supra-orbital nerve and artery. Beneath the supra-orbital ridges 

 are the openings of the orbits. Between the orbits is the bridge of 



