58 PRACTICAL ANATOMY. 



strong, fiat, quadrilateral processes of bone at right 

 angles to the body. They present for examination an 

 external and internal surfaces an anterior, posterior, su- 

 perior, and inferior border; an angle, and two processes. 

 The external surface is smooth, flat, and presents some 

 elevations and ridges for the attachment of the masseter 

 muscle. The internal surface is very uneven. About 

 its centre is the inferior dental foramen, leading into the 

 inferior dental canal, which is directed obliquely down- 

 ward and forward. The approach to the inferior dental 

 foramen from above is funnel-shaped and grooved at 

 the expense of the inner surface of the ramus. Over- 

 lapping the foramen is a sharp lip of bone, deeply-notched 

 on its upper edge ; it gives attachment to the internal 

 lateral ligament of the jaw. Running downward and 

 forward from the lower border of the inferior dental fora- 

 men is a well-marked groove, the mylo-hyoid, which 

 lodges the mylo-hyoid artery and nerve. At the posterior 

 lower portion is a well-marked, shallow fossa, the pos- 

 terior margin of which is very rough; it serves for the 

 attachment of the internal pterygoid muscle. Above the 

 foramen the bone is flattened and beveled up to the 

 superior border. The anterior border is thin and 

 sharp, and continuous with the external oblique line; 

 it terminates above in a flattened, triangular process, 

 the coronoid, which gives attachment to the temporal 

 muscle. The superior border is strongly concave and 

 sharp, and forms the sigmoid notch ; it runs from the 

 coronoid process anteriorly to the condyloid process, 

 which projects upward and backward from the posterior 

 angle of the superior border. It is a strong process of 

 bone, compressed antero-posteriorly, and surmounted by 

 the condyle, which articulates with the gienoid fossa of 

 the temporal bone. The condyle is directed outward 



