DISSECTING MANUAL. 



fissures, and lies between the superior maxilla and root of the 

 pterygoid process of the sphenoid. The vertical plate of the 

 palate bone forms its inner wall, and presents a large (spheno- 

 palatine) foramen leading between the orbital and sphenoidal 

 processes of the palate bone into the nose. The body of the 

 sphenoid and orbital plate of the palate bone form its roof. 

 Opening into it above and behind are the foramen rotundum, 

 Vidian canal, and ptery go-palatine canal from without inward, 

 while below are the upper end of the posterior palatine canal and 

 the orifices of the accessory posterior palatine canals. [158] 



Posterior Aspect (norma occipitalis) . This includes the 

 parietal and occipital bones and the mastoid portions of the 

 temporals. The interparietal (sagittal) suture meets (at the 

 lambda) the occipito-parietal (lambdoid) suture; separated 

 ossicles (Wormian bones) may be found in the lambdoid su- 

 ture. A (parietal) foramen is found on each parietal not far 

 above the lambda and close to the sagittal suture ; the point 

 on the suture between the foramina is the obelion. At the cen- 

 tre of the tabular part of the occipital is a projection (external 

 occipital protuberance) from which a ridge (superior curved 

 line) runs outward on each side to the lateral angle (at the 

 asterion) ; just above this ridge is another faint one (highest 

 curved line) . A mesial ridge (external occipital crest) descends 

 from the protuberance to the foramen magnum ; from its cen- 

 tre a ridge (inferior curved line) runs outward on each side, 

 parallel to the others. [159] 



Superior Aspect (norma verticalis). The sagittal (inter- 

 parietal) suture joins the coronal (fron to-parietal) in front (at 

 the bregma) and the lambdoid (occipito-parietal) behind (at the 

 lambda). The temporal ridge crosses the coronal suture (at 

 the stephaniori) . The vault is rounded and its highest point 

 (vertex) is in the sagittal suture. [159] 



Inferior Aspect or Base (norma basalis). This is best de- 

 scribed in detail, from before backward. The hard palate is a 

 horseshoe-shaped plate in front, formed by the palatal proc- 



[10] 



