NERVOUS SYSTEMS, PERIPHERAL AND CENTRAL 483 



Fid. 149. 



PLATE OF THE BASE OF THE HITMAN BRAIN, SHOWING THE CRANIAL NERVES AND 

 THE CIRCLE OF WlLLIS. 



The following is the description given by Willis : 



A, A, A, A, Cerebri quadripartiti anteriores posterioresque 0, O, 



lobi. P, P, 



B, B, Cerebellum. 



C, C, Medulla oblongata. Q, Q, 



D, D, Nervi olfactorii, sive par primum. It, 



A', E, Nervi optici, sive par secundum. 



F, F, Nervi oculorum motorii, sive par tertium. S, 



O, O, Nervi oculorum pathetici, sive par quartum. 

 H, B, Nervorum par quintum. T, T, T, 



/, /, Nervorum par sextum. 

 K, K, K, K, Nervi auditorii, et eorum utrinque bini pro- F, 



cessus, par septimum. 

 L, L, I, I, I, etc., Par vagum, sive octavum, pluribus fibris W,W, 



constans. 

 M, M, Nervus spinalis, ad originem paris vagi a 



longinquo accedens. X, 



N, N, Par iionuni, pluribus etiam fibris constans Y, K, 



(quae deorsum tendentes, in eundem a, a, a, a, 

 truncum coalescunt) qui paulo supra 

 processum occipitis emergit. 



Par decimum deorsum tendens. 



Arteria carotidis truncus abscissus, ubi in ramnni 



anteriorem et posteriorem dividitur. 

 Ejus ramus inter duos cerebri lobos incedens. 

 Carotidnm rami anteriores uniti abscedunt, in 



cerebri fissuram pergentes. 

 Carotidum rami posteriores uniti, et trunco 



vertebrali occurrentes. 

 Arteriae vertebrales, et earum tres rami ascen- 



dentes. 

 Vertebralium rami in eundem truncum coal- 



escentes. 

 Locus designatur, ubi arteriae vertebrales et 



carotides uniuntur, et utrinque ramus ad 



plexum chorceiden ascendit. 

 Infundibulum. 



DUBS glandulse pone infundibulum consitae. 

 Protuberantia annularis qusD a cerebello dimisa 



medulla oblongata caudicem amplectitur. 



(Willis, 1680, PI. 1. Drawn by Christopher Wren. See text, page 484. 



