THE PILTDOWN MANDIBLE 
441 
thus masticating the food. One of these is the temporal 
muscle, which rises from the side of the skull and is 
attached to the coronoid process. The two others are 
also important for our present purposes and must be 
mentioned. One is the masseter, which rises from the 
zygoma (fig. 163) and is attached to the outer surface of 
the ramus of the jaw, especially in the neighbourhood 
of the angle. On the deep surface of the ramus there 
is a counterpart to the masseter muscle — the internal 
12 3 
MODERN 
ENGLISH. V •-. 
PILTDOWN 
Fig. 163. — Side view of the lower jaw and mandibular joint in a modern skull. 
The stippled line represents the position of parts when the mouth is shut ; 
the firm line, the open position. The corresponding parts of the Piltdown 
skull are also shown in the drawing. 
pterygoid. Now, it will be seen from fig. 163 that as 
the mouth opens under the action of the external ptery- 
goid and the forward movement of the condyle is 
initiated, the coronoid process is moved forwards and 
downwards, elongating the temporal, while the angle 
moves backwards and downwards, stretching the 
masseter and internal pterygoids, bringing them into an 
advantageous position for executing a grinding move- 
ment. The part played by the articular eminence in the 
mechanism of opening the mouth will be evident. The 
resistance it offers to the forward movement of the 
