24 A MANUAL OF ANATOMY. 



intraparietal line is the ascending parietal convolution, 

 the region between the second part of the sulcus and the 

 median line is the superior parietal convolution, and the 

 area within the arch of the intraparietal sulcus is the infe- 

 rior parietal convolution. 



The Temporal Lobe. The sulci are indicated by two 

 lines drawn backward and upward parallel with the hori- 

 zontal limb of the fissure of Sylvius, the first three- 

 fourths of an inch from the Sylvian fissure and the second 

 one and one-half inches from the same. 



The first temporal convolution corresponds to the 

 region between the Sylvian fissure and the first sulcus, the 

 middle convolution to the area between the first and 

 second sulcus, and the inferior convolution to that below 

 the last sulcus. 



The Occipital Lobe. This agrees with the area behind 

 the parieto-occipital fissure. Its divisions into convolutions 

 is by incomplete sulci, and both convolutions and sulci 

 are unimportant. 



The Reg-ion of the Pace. The infra-orbital arch limits 

 the orbital cavity below. It leads outward to the malar 

 bone, which varies in prominence with races and individuals. 

 The margins of the lower jaw, posterior and lower, and the 

 angle (formed by their junction) can easily be recognized. 

 The lower border of the jaw, the tip of the mastoid process, 

 a line connecting the angle of the jaw with the tip, and the 

 superior curved line of the occipital bone form the arti- 

 ficial and natural boundary between the head and neck. 



DISSECTION. 



Support the head properly by suitable blocks for convenience of dissection. 

 Incisions. I. From the root of the nose (nasion) in the median line to the 

 occipital protuberance (inion). 



