226 



COMPARATIVE ANATOMY 



frontal bone are the large frontal sinuses. Articulating with the frontals 

 and forming the greater part of the roof and sides of the cranium are the 

 paired parietals. Curved ridges on the sides of the parietals mark the 

 origin of the temporalis muscle. See Fig. 185. 



The occipital bone articulates with the parietals and forms the most 

 posterior of the roofing bones of the skull. Through a large median 



NASAL 



LACRIMAL 



MAXILLA 



ZYGOMATIC 



MECKEL'S CART'^ 



MANDIBLE 



STYLOID PROCESS 



MAXILLA, 

 PALATINE 

 ZYGOMATIC 



STYLOID PROCESS 

 AUDITORY MEATUS - 



PARIETAL 



FORAMEN LACERUM 

 TEMPORAL. OCCIPITAL CCTCYLE 



PARIETAL 

 CHONDRDCRANIUM 



FORAMEN MAGNUM 



OCCIPITAL' 



NASAL CONCHA 



OCCIPITAL 

 TEMPORAL 

 MASTOID PROCESS 

 'AUDITORY MEATUS 

 ZYGOMATIC ARCH 



Fig. 185. — The human skull, embryonic (A) and adult {B-D). In the fetal skull 

 (14 weeks) membrane bones are black, and the cartilage cranium (chondrocranium) 

 stippled. Figure B shows the adult skull in basal aspect, figure C in frontal aspect, and 

 figure D in left lateral aspect, approximately one quarter natural size. (Redrawn after 

 Sobotta.) 



aperture, the foramen magnum, the spinal cord passes from the vertebral 

 canal into the cranium to connect with the brain. Many of the neck 

 muscles are inserted on the basal portion of the occipital. On each side 

 of the foramen magnum the occipital condyles form the articulation of 

 the cranium with the atlas vertebra. 



The sphenoid bone, at the base and sides of the cranium in front of the 

 occipital, is in form the most complex of the cranial bones. It has a 

 median body and two pairs of wings, the lesser and the greater. Paired 

 pterygoid processes project downward and backward toward the pharynx. 



