36 SURGICAL APPLIED ANATOMY. [Chap. in. 



fissure, and in front and behind by the two vertical 

 lines. A diagonal line D E drawn from the posterior 

 superior angle to the anterior inferior angle of the 

 space will be over the fissure of Rolando. In the 

 adult, the upper end of the fissure lies half an inch 

 behind the centre of the median line of the head, 

 measured fi-om the root of the nose to the occipital 

 protuberance (Thane). The line of the fissure forms 

 with the median line of the head an angle of about 

 67 (Hare). 



The parieto-occipital fissure runs outwards and 

 a little forwards on the brain for about one inch. 

 It is nearly at right angles to the longitudinal fissure, 

 and lies from 2 to 3 mm. in front of the lambda 

 (Horsley). 



Frontal lobe. A. line drawn backwards from 

 the supraorbital notch to within f of an inch of the 

 line for the fissure of Rolando, and parallel with the 

 longitudinal fissure, will mark the superior frontal 

 sulcus. The frontal part of the temporal ridge will 

 indicate the second frontal sulcus. The first, second, 

 and third frontal convolutions will thus be mapped 

 out. The ascending frontal convolution will occupy 

 a space about f of an inch broad, parallel with, and 

 in front of, the Rolandic line. 



Parietal lobe. The intraparietal sulcus commences 

 near the horizontal limb of the Sylvian fissure, and 

 ascends midway between the line of the fissure of 

 Rolando and the centre of the parietal eminence. It 

 reaches a point below the horizontal level of the 

 superior frontal sulcus, and then turns backwards to 

 run midway between the longitudinal fissure and the 

 centre of the parietal eminence (Horsley). In the 

 space above this sulcus there is in front, parallel 

 with the whole length of the fissui*e of Rolando, the 

 ascending parietal convolution, and behind the 

 superior parietal lobule. The space below the sulcus 



