CRANIUM AND SCALP 



1081 



in front of the oar, while fnun its anterior extremity the fnifier, carried upwards 

 along the outline of the malar, traces the temj>orai ridge along the side of the 

 skull which marks the ui)per limit of the temporal fossa, and the attachments of 

 the temporal muscle and fascia. In tlu; temporal fossa lie the muscle, and the 

 deej) temporal vessels and nerves. Al)Ove the zygoma can he felt the" ccjntraction 

 of the temporal; and below, that of the masseter nmscle; the former less distinctly 

 owing to its covering of fascia, attached below by two layers to the U]»i)er border 

 of the zygoma. In the zygomatic fossa, lying inside the zygoma, arc the lower 

 part of the temporal, and the two pterygoid muscles, together with the internal 

 maxillary vessels, and the mandibular division of the fifth nerve, an<l their 

 branches. 



The anterior inferior angle of the parietal bone, and its great importance as a 



Fig. 659.— The Skull. 



BREGMA 



GLABELLA NAS 



(THE POINTER 



landmark, has alreadv been given. The posterior inferior angle of this V)one 

 (grooved l>v the lateral sinus) lies a little above and behind the base of the 

 nTastoid. on a level with the roots of the zygoma (tig. 055)). Just below and in 

 front of the tij) of the mastoid the transverse process of the atlas can W made out 

 in a spare sul»ject. ^ , , • , 



The average thickness of the adult skull-cai> is about one-lifth of an mch 

 (Holden). The thickest i>art is at the external occipital j.rotubcrance, where the 

 bone is often three-quarters of an inch in thickness. The thinnest i)art of the skull 

 vault is over the temporal part of the sciuamous. The extreme fragility of the 

 skull here is partlv c<jmpensated for by the thickness of the soft parts; (»f these. 

 the pericranium is alone thinner than elsewhere, while its intimate connection 

 with the bones make cephallutmatoma less frequent here (Tillaux). 



