THE SKULL. 47 



Near the middle of its cranial border it is notched obliquely 

 by a foramen (<^), the beginning of the nasolachrymal canal. 



Malar Bone. Jugal Bone. Os zygomaticum (Fig. 35). 

 — The malar or zygomatic bone is a flat curved plate of bone 

 which forms the lateral wall of the orbit and together with the 

 zygomatic process of the temporal forms the zygomatic arch. 

 Its outer surface is smooth and marked by a longitudinal ridge 

 {a) for attachment of the masseter muscle. 



At its caudal end the bone is continued into two processes : 

 one, the frontal process or orbital process {d), is a triangular 

 spine of bone directed caudomediad ; when the bones are 

 articulated it lies opposite the zygomatic process of the frontal 

 to which it is joined by a ligament (orbital ligament). The 

 other, zygomatic process {c) of the malar bone, extends vcn- 

 trocaudad and articulates with a similar process from the tem- 

 poral to form the zygomatic arch above mentioned. 



Its inner surface is smooth and looks into the orbit, except 

 that of the zygomatic process, which looks into the temporal 

 fossa. 



Its cranial border is roughened at the expense of both sur- 

 faces and articulates with the maxillary bone. Its other 

 borders are smooth except the dorsal border of the zygomatic 

 process, which is roughened for attachment to the zygomatic 

 process of the temporal. 



The Mandible. Mandibula (Figs. 36 and 37). The 



mandible (or inferior maxillary bone) is composed of two 

 halves which come together at the cranial end and form the 

 lower jaw. At its caudal end each half articulates with the 

 temporal bone at the mandibular fossa, and at its cranial end it 

 joins the opposite bone, the suture being known as the sym- 

 physis of the jaw (symphysis menti) (Fig. t,-/ , a). 



Each half consists of a horizontal portion, the body {b), 

 bearing teeth on one of its borders (the alveolar border), and 

 of a vertical portion, the ramus {c). 



The body {b) has the form of a flattened cylinder and has 

 two surfaces and two borders. The lateral surface (Fig. 36) 

 is smooth and presents near its cranial end a foramen (or 

 sometimes two), the mental foramen [d), forming the cranial 



