DISSECTING MANUAL. 



symphysis is a hollow (incisor fossa) . The inferior border is 

 rounded. On the internal surface, on each side, a ridge (mylo- 

 hyoid; internal oblique line) runs, from behind and above, 

 downward and forward to the lower part of the symphysis; 

 below the ridge posteriorly is a fossa for the submaxillary 

 gland; at the junction of both ridges, in the midline ante- 

 riorly, is a raised tubercle with two, or two pairs of laterally 

 placed, spines (mental, or genial spines). [143] 



Ramus. This ascends from the back of the body; its pos- 

 terior border forms an angle, usually everted, with the base of 

 the body. Its outer surface may present obliquely curved 

 ridges. Its inner surface presents mesially a foramen (inferior 

 dental) which is overhung in front by a projection (lingula) ; 

 a groove (mylo-hyoid) descends from the foramen behind the 

 lingula. Superiorly the ramus supports two processes which 

 are separated by a wide notch (sigmoid). The condyle is the 

 posterior process; it is convex, elongated transversely, and 

 supported on a neck which is compressed antero-posteriorly ; 

 on the inner side of the neck is a depression for the External 

 pterygoid. The coronoid process is a triangular elevation which 

 lies in front, its anterior border joining that of the ramus; be- 

 hind this border, on the inner side, is a triangular groove 

 whose inner border joins the internal oblique line. [144] 



The hyoid bone lies in the neck, between the mandible and 

 the larynx; it has a U-shaped body with four processes 

 (cornua). The body is compressed antero-posteriorly; its an- 

 terior surface presents a median vertical ridge; its posterior 

 surface is concave; its upper border is broad arid bounded in 

 front by a transverse ridge, and behind by a thin edge. From 

 each end of the body a process (great cornu) curves upward and 

 backward, being compressed laterally but expanded at its end. 

 A small process (lesser cornu) projects upward, backward, and 

 slightly outward from the upper surface, on each side, at the 

 junction of the body and the great cornu; it is often partly 

 cartilaginous. [147] 



[4] 



