738 



CRANIUM. 



orbitar plate on the other ; the junction of this 

 mass to the body of the sphenoid ; the turbi- 

 nated process of the same bone, and, some- 

 times, the opening into its sinus ; the articular 

 surface for the palate bone; and, lastly, the 

 base of the pterygoid process exhibiting the 

 anterior orifice of the Vidian canal. 



Still more outwardly is the part which forms 

 the orbit, concave, and broader before than 

 behind. To the fore part there are, on the 

 outer side, the lachrymal fossa ; on the inner 

 side the trochlear fossa, and, near to it, the 

 orbitar orifice of the supra-orbitary foramen. 

 Further back there is on the inner side a por- 

 tion of the transverse suture between the 

 frontal and ethmoidal bones, containing the 

 two internal orbitar foramina ; and, to the 

 outer side, another portion of the same suture 

 between the frontal and sphenoid. A third, 

 shorter portion connects the two preceding, 

 and unites the frontal to the small wing of the 

 sphenoid. Behind this there are in succession 

 the foramen opticum ; the foramen lacerum 

 orbitale superius ; the foramen rotundum ; 

 and, lastly, the sulcus temporalis leading from 

 the last foramen, and being behind the orbitar 

 process of the sphenoid bone. 



The middle division offers in its centre the 

 basilar process of the occipital bone, and the 

 line of its junction with the sphenoid. On it 

 are seen the indications of the attachment of 

 the pharyngeal and anterior recti muscles. 

 Its posterior edge forms a segment of a circle 

 to assist in forming the foramen magnum. 

 On either side, and from before backwards, 

 are the external and internal pterygoid pro- 

 cesses, with the fossa navicularis, fossa ptery- 

 goidea, and hiatus palatinus between the two 

 processes; the posterior orifice of the Vidian 

 canal ; the foramen lacerum anterius ; the 

 under surface of the petrous process of the 

 temporal bone, with, on one side, the line of 

 its junction with the basilar process, and, on 

 the other, the line of its junction with the 

 sphenoid bone, the Eustachian sulcus occu- 

 pying the latter ; behind the foramen lacerum 

 anterius is the rough surface for the origin of 

 the levator palati and tensor tympani muscles; 

 the inferior orifice of the carotid canal ; the 

 opening of the aqueduct of the cochlea ; and, 

 lastly, the foramen lacerum posterius. More 

 outwardly, and pursuing the same direction, 

 are the under surface of the great wing of the 

 sphenoid bone; its line of union with the 

 temporal ; the processus articularis ; the fossa 

 articularis ; the Glasserian fissure ; the fossa 

 parotidea ; and, lastly, the rough inferior bor- 

 der of the foramen auditorium externum. On 

 the inner edge of this plane, and to the outer 

 side of the sulcus Eustachianus, there are, 

 successively, the foramen ovale ; the foramen 

 spinale ; the styloid process ; the spinous pro- 

 cess, which is wedged into the Glasserian fis- 

 sure; the crest between the fossa parotidea 

 and the foramen lacerum posterius ; the vagi- 

 nal process and the styloid process. 



The posterior division exhibits, on the me- 

 dian line, the foramen magnum ; the longi- 

 tudinal spine bisecting the inferior curved 



ridge, and having, on each side, below that 

 ridge, rough depressions for the attachment 

 of the posterior recti muscles, and above that 

 ridge, still stronger and larger marks of the 

 attachment of the complexus ; and, lastly, the 

 inferior aspect of the occipital protuberance. 

 To the extreme outside and passing from behind 

 forwards, there are the termination of the 

 superior occipital ridge; the additamentum 

 suturae lambdoidalis ; the posterior part of the 

 mastoid portion of the temporal bone dis- 

 playing the foramen mastoideum ; the sulcus 

 occipitalis on one hand, the mammillary pro- 

 cess of the mastoid portion of the temporal 

 bone on the other, and the sulcus digastricus 

 between the two; and, lastly, the foramen 

 stylo-mastoideum at the bottom of the sulcus 

 digastricus. Midway, and between the me- 

 dian and outer portions of this region, and still 

 passing from behind forwards, there are, the 

 superior occipital ridge, the inferior occipital 

 ridge, and between them the marks of the 

 attachment of the splenius capitis and trachelo- 

 mastoideus; the oblique surface into which 

 the obliquus capitis superior is inserted ; the 

 posterior condyloid fossa, containing the pos- 

 terior condyloid foramen whenever it exists ; 

 the condyle itself; the anterior condyloid fossa 

 and foramen ; and, lastly, to the outside of the 

 condyle, the processus lateralis. 



The lateral region (fg. 373) is oval, and its 

 boundaries have already been stated. Its sur- 

 face, lengthwise, is undulated, being convex 

 behind, where the temporal and parietal form it; 

 and concave in front, where the temporal and 

 sphenoidal enter into its composition. Pro- 

 ceeding from above downwards, and com- 

 mencing with the linea temporalis, we have 

 so much of the parietal and frontal bones as 

 are below that line, with the inferior extremity 

 of the coronal suture between them; next, 

 the sutura squamosa between the parietal and 

 temporal bones, and part of the transverse 

 suture between the frontal and sphenoid ; 

 below tli is, the squamous process of the tem- 

 poral bone, and, in front of it, the temporal 

 process of the sphenoid with the line of arti- 

 culation between them. These parts form the 

 fossa temporalis, which is limited inferiorly, 

 on the sphenoid by a crest which divides it 

 from the jugal fossa belonging to the face, and 

 on the temporal by a groove on the upper part 

 of the two roots of the zygomatic process, in 

 which play the posterior horizontal fibres of 

 the temporal muscle. Passing from behind 

 forwards, there will be observed at the lower 

 boundary of this region, the additamentum 

 suturae squamosse ; the base of the mastoid 

 process; the foramen auditorium externum; 

 and, lastly, the zygomatic process of the tem- 

 poral bone articulating anteriorly with the 

 malar bone. 



The interior of the cranium presents through- 

 out its entire extent more or less evidence of 

 the adaptation of its surface to the convolutions 

 of the brain. 



The base is bounded, in front by the fora- 

 men coecum ; behind, by the centre of the 

 internal crucial spine; and, in its circumfe- 



