1, Occipital condyle; 2, condyloid fossa; 3, paramastoid or styloid process; 4, occipital crest; 5, external occipital protuberance; 6, external auditory meatus; 7, mastoid process; 8, hyoid process; 9, stylo-mastoid foramen; 10, muscular process; 11, foramen lacerum anterius; 12, postglenoid process; 13, glenoid cavity; 14, temporal condyle; 15, Vidian groove; 16, alar canal of pterygoid process indicated by arrow; 17, temporal foramen; 18, ethmoidal foramen; 19, optic foramen; 20, foramen lacerum orbitale; 21, maxillary foramen; 22, sphenopalatine foramen; 23, posterior palatine foramen; 24, supraorbital foramen (opened); 25, lacrimal fossa; 26, depression for origin of obliquus oculi inferior; 27, facial crest; 28, maxillary tuberosity; 29, alveolar tuberosity; 30, hamulus of pterygoid bone; _S.o._, supraoccipital; _P_, parietal; _S_, squamous temporal; _B.o._, basioccipital; _B.s._, basisphenoid; _A.t._, temporal wing of sphenoid; _A.o._, orbital wing of sphenoid; _Pt.p._, pterygoid process of sphenoid; _P.p._, perpendicular part of palate bone; _F,F′_, facial and orbital parts of frontal bone; _L,L′_, orbital and facial parts of lacrimal bone; _M_, facial part of malar bone; _M.x._, maxilla; _a_, parieto-occipital suture; _b_, parieto-temporal or squamous suture; _c_, _d_, spheno-squamous suture; _e_, palato-frontal suture; _f_, fronto-lacrimal suture. ] The =lateral surface= (Norma lateralis) may be divided into cranial, orbital, and maxillary or preorbital regions. The =cranial region= presents the temporal fossa, the zygomatic arch, and the outer part of the petrous temporal bone. The =temporal fossa= is bounded internally by the sagittal and frontal crests, externally by the temporal crest and the zygomatic arch, and behind by the occipital crest. Its upper and middle parts are rough for the attachment of the temporal muscle. In its lower posterior part are several =foramina= which communicate with the parieto-temporal canal. The fossa is continuous in front with the orbital cavity. The =zygomatic arch= is formed by the zygomatic processes of the temporal, malar, and maxilla. Its ventral face presents the =condyle= and =glenoid cavity= for articulation with the lower jaw, through the medium of the articular disc. Behind the glenoid cavity is the =postglenoid process=. The =external auditory process= projects outward through a deep notch in the lower margin of the squamous temporal below the temporal crest. A little further back is the =mastoid process=, crossed in its upper part by a groove for the mastoid artery. The =orbital region= comprises the orbit and the pterygo-palatine =fossa=.