Fig. 17. Projection of Lateral Ventricle, Middle Ear and Lateral 

 Sinus on the outer surface of the Skull. 



To SpitzKj^s figure which shews the projection of the Lateral Ventricle on to 



the outer region of the SkxiU, we have added the projection of the Lateral 



Sinus (violet) and of the Middle Ear with its Accessory Cavities (red) while 



retaining our own Specimens and the indications by Frjedrich Muller. 



Puncture of the Lateral Ventricle is performed (a) to emptj' it of accumu- 

 lated fluid (Hydrocephalus, Serous Meningitis etc.), or (b) to inject drugs into the 

 Ventricle when not dilated (e. g. Tetanus). 



vox Bergmann trephines the Skull in front, directlj' above and mesial 

 to the Frontal Eminence and pushes a long hollow needle in a slightly downward 

 and inward direction. 



Keen finds a point on the outer surface of the Skull 3 1 mm. above a line 

 connecting the lower border of the Orbit with the External Occipital Protuberance 

 and 32 mm. behind the External Auditory Meatus. 



The shape of the Lateral Ventricle does not vary much except in the 

 Posterior Horn. The "Trigone" i. e. where the Body, the Posterior and Descending 

 Horns meet, is the largest part and consequent!}' the most suitable for the 

 operation. 



Fig. 18. Projection of the Middle Meningeal Artery on the outer 



surface of the Skull. 



After Kronlein. The Middle Meningeal Artery is red. 



To determine certain important Cerebral points and lines, as well as the 

 Middle Meningeal Arterj', Kroklein's landmarks are the most convenient. 



i) The "German Horizontal Line" runs through the Infra-Orbital margin, 

 and the upper border of the External Auditory Meatus. 2) The "Upper Horizontal 

 Line" runs through the Supra-Orbital margin, parallel with the former. 3) The 

 "Anterior Vertical Line" passes upward from the middle of the Zygoma at right 

 angles to i). 4) The "Middle Vertical Line" passes from the Condyle of the 

 Lower Jaw at right angles to i). 5) The "Posterior Vertical Line" from the 

 posterior margin of the Base of the Mastoid Process at right angles to i). 



A line connecting (a) the point where the "Anterior Vertical Line" and 

 the upper Horizontal Line cross each other with (b) the point where the "Posterior 

 Vertical Line" cuts the ^^ertex, represents the Central Fissure (ROLANDO). When 

 the angle formed by this line and the upper Horizontal line is bisected by a line 

 drawn to meet the posterior vertical line, the oblique line represents the Fissure 

 of Sylvius. 



A and B are the points for trephining to evacuate the blood extravasated 

 from a ruptured Middle Meningeal Arter}'. 



The square marked in thick Unes is the region in which VOX Bergjl\X'X 

 resects the SkuU cap for drainage of Otitic Abscess and Abscess of the Tem- 

 poral Lobe. 



The Black Circles indicate the following points which are often made use 

 of (cf. Text Figs. 1 1 and 1 2) : 



Nasion at root of Nose. Bregma at Vertex; further back, Obelion, Lambda; 

 and Inion at the External Occipital Protuberance. 



