184 



HEALTH AND DISEASE 



Occiput. — This bone is situated at the supei'ior extremity of the 

 cranium, and, as we have already pointed out, furnishes two large con- 

 dyles, by which it articulates with the atlas, or first bone of the neck 



(15, fig. 289). Above, it forms 

 the crest or prominence between 

 the ears, while below it gives off 

 a process (basilar j^rocess) which 

 passes forward to assist in fonu- 

 ing the base of the skull. Be- 

 hind, it forms the superior boun- 

 dary of the cranium, where it 

 presents two rounded projections 

 or condyles. Between these is a 

 large opening [foramen magnum), 

 through which the brain is con- 

 nected with the spinal cord. On 

 the outer side of the occipital con- 

 dyles a bony projection [styloid 

 process) is found. This, like other 

 parts of the bone, affords attach- 

 ment to important muscles. 



Parietal. ^The jjarietal bones 

 are two, situated immediately be- 

 neath the bone last described and 

 aho^■e the frontal bones. They are 

 united by the sagittal suture in the 

 middle line of the cranium, and 

 serve to form the roof of that cavitv. 



Temporal Bones. — These 



are four in nunil)er, two pairs, dis- 

 tinguished from each other as the 

 squamous and the petrous tem- 

 poral bones, the former having a 

 shell-like structure, while the latter 

 are of great density and hardness. 

 The petrous temporal bones con- 

 tain the organs of hearing. 

 Squamous Temporal. — These are two flattened portions of bone 

 situated at, and forming the sides of, the brain cavity. From the outer 

 part, near the middle, a long bony eminence proceeds in a downward direc- 

 tion to unite with the orbital process of the frontal bone above, and the 



Fig. 287.— Skull (Front Aspect) 



1 Occipital Tuberosity. - Parietal Bone. ^ Squamous 

 Temporal Bone. * Superior Orbital Foramen. ^ Lacli- 

 rymal Bone. ^ Malar Bone. " Inferior Orbital Foramen. 

 ^ Foramen Incissivum. •' Anterior Maxillary Bone. '" Nasal 

 Suture. ^' Superior Maxillary Bone. '- Fi-oiital Bone. 

 " Frontal Suture. '* Temporal Fossa. '^ Sagittal Sutui'e. 



