112 THE MUSCLES, 
process for about one centimeter into a fascia common to it and 
the masseter muscle, and into the stylomandibular ligament. 
Relations.—Ventral surface with the styloglossus and the 
Fic. 66.—OBLIQUELY VENTRAL VIEW OF THE DEEP MUSCLES OF THE LOWER 
Jaw AND PALATE. 
The tongue and other structures forming the floor of the mouth have been re- 
moved, showing the roof of the mouth. On the right side the masseter and ptery- 
goideus internus have been removed. a, a’, M. masseter; 4, M, pterygoideus ex- 
ternus; ¢, M. pterygoideus internus; ¢, ¢’, M. tensor veli palatini; ¢, e’, M. levator 
velj palatini;  M. constrictor pharyngis superior. 1, aponeurosis of the velum 
palatinum; 2, ridges formed by the palatines and pterygoid portions of the sphenoid; 
3, hamular processes; 4, free caudal border of the velum palatinum; 5, bulla tym- 
pani. 
soft palate. Dorsal surface with the bulla tympani (5) and 
base of the skull. Cranial surface with the pterygoideus 
externus (4), with which it is partly united. 
Action.—Assists the pterygoideus externus. 
(6) Muscles of the Hyoid Bone. 
M. stylohyoideus (Fig. 65, d).—The stylohyoid is a 
ribbon-like muscle about three millimeters wide. It lies on 
