EXAMINATION OF SOME SPINAL NERVES 59 
arch ; between these points the lower part of the curve is slightly concave forward, the upper 
part slightly convex forward. Ascending then upon the temporal muscle, the course taken is 
again that of a line with a slight concavity forwards. The vertex is approached most nearly 
opposite the junction of the coronal and sagittal sutures (bregma) ; the middle line is, however, 
not actually reached. I have paid particular attention to this point in three experiments, and am 
convinced that the field of the mandibular division of the Vth, although it approaches near to the 
middle line of the scalp, does not actually attain to it. It however extends higher than as given 
Anterior border 
of field of Ilnd 
cervical nerve. 
? v indicates - the limit of the 1st division of the Vth, 5a. 
field attached to the limit of the 2nd division of the Vth, 5/3. 
the vagus nerve the limit of the 3rd division of the Vth, 5^. 
for Man in Flower's atlas of nerve fields. The boundary becomes identical witii the posterior 
boundary of the skin-field of the entire Vth about 3 centims. from the mid-dorsal line ; after that 
junction the boundary is that described above under the posterior boundary of the skin-field of 
the Vth on page 53. The control experiment of estimating tlie field of the 3rd division, and 
then severing the nerve, I have carried out once. On severing the 3rd division, the anterior 
boundary of the field which had previously lain between the angle of the mouth and the zygoma 
retreated to the pinna of tlie car, ramus of jaw, and thyroid cartilage (vide infra, p. 68, Ilird 
cervical nerve). 
