BONES OF THE CRANIUM. 183 



transmits the spinal marrow and its membranes, the ver- 

 tebral arteries and the spinal-accessory and sub-occipital 

 nerves. In front of it is the cuneiform or basilar process, 

 which extends forward upon the base of the cranium to 

 unite with the sphenoid bone. The inferior surface of this 

 process is rough and gives attachment to the pharynx, and 

 superior and middle constrictor muscles. 



On each side of the foramen magnum and near its fore- 

 part, are the two oondyles for articulating with the atlas. 

 They are smooth oblong processes which converge ante- 

 riorly, and look downwards and outwards, posteriorly. In 

 front and at their base, is the anterior oondyloid for amen, for 

 transmitting the ninth or lingual nerves, and behind is a 

 small foramen, the posterior condyloid, for the passage 

 of a vein to the lateral 

 sinus. Each condyle has 

 on its outside the jugular 

 eminence or transverse 

 process, which forms the 

 posterior boundary of the 

 foramen lacerum basis 

 cranii posterius, and to 

 which is attached the rec- 

 tus lateralis muscle. 



The internal or cerebral 

 surface is concave, and in- v / 



tersected by the crucial * ' j 



ridge, which divides it into four occipital fosses, two superior 

 for lodging the posterior lobes of the cerebrum, and two 

 inferior for the cerebellum. In the centre where these 

 ridges cross each other, is the internal-occipital protuberance, 



FIG. 39 represents the internal surface of the Occipital Bone, a Foramen 

 magnum. 6 Ridge for falx-minor. c Internal occipital protuberance, d d 

 Lateral branches of the occipital cross, and depression for lateral sinus, e Sur- 

 face for parietal bones. / Jugular eminence, g Jugular fossa, 'h Internal 

 opening of condyloid foramen, i Surface for petrous portion of temporal bone, 

 j j Condyles. k Anterior extremity of cuneiform process. I I Exterior edge 

 of basilar gutter, m m Surface for mastoid portion of temporal, n n Cavity 

 for Cerebellum, o o Cavity for posterior lobes of cerebrum. 



