326 
MR. BELL ON THE NERVES OF THE FACE. 
I was consulted in the case of a lady with an uncommon disease in the side 
of the head : the description of her condition puzzled me very much ; there was 
so much said of tumours with pulsation on the head and face. But when I 
saw and examined her, the mystery disappeared ; she had powerful spasms of 
the temporal and masseter muscles, which rose and swelled, under the excite- 
ment of a disease of the cheek, and with a pressure of the jaws so powerful as 
to displace the teeth. During this violent spasm of the muscles supplied by 
the fifth nerve, the motions of the features were free and unconstrained under 
the influence of the portio dura of the seventh nerve. 
I have the precise counter-part to this morbid condition of the muscles of 
mastication in the case of a poor man now under my care. He has a disease 
affecting the fifth nerve of the left side, attended with the loss of sensibility of 
the side of the face and of the surfaces of the eye. In him there is no motion 
of the muscles of the jaw of the affected side. In chewing, the action is only 
on the right side of the head ; the masseter muscle and temporal muscle of the 
left side do not rise or bulge out as in their natural actions ; but his command 
over his features is perfect through the operation of the portio dura. It ap- 
pears, therefore, that the disease of the fifth nerve, which has destroyed the 
sensibility on one side of the face, has caused a loss of motion in the muscles 
of the jaw on the same side. 
A more frequent occurrence establishing the distinction of motions influenced 
by the fifth and seventh nerves, is presented in the case of paralysis of the portio 
dura ; for then all the muscles waste but those supplied by the fifth. In the 
case referred to, of the man wounded by the horn of an ox, in whom the portio 
dura was torn, and who had the skin of his forehead, side of the nose, cheek 
and lips, deprived of all fleshiness and substance, and in fact wasted to mere 
skin, the muscles of the jaw were entire and prominent ; and on introducing 
the finger into the mouth and making him imitate the motions of mastication, 
a weak contraction could be felt in the cheek*. 
These facts close the evidence of the fifth nerve being a double nerve ; not 
only the nerve of sensibility to the head and face, but a muscular nerve to the 
muscles of the jaws, active in mastication, and otherwise useful in all animals 
• I low often a question has occurred as to this motion in the cheeks, may be seen on referring to 
cases, p. 123, Exposition, &c. and p. 57, Appendix, 1st edition. 
