28 THE MENINGES OF THE BRAIN. 



which it is separated by the oculomotor nerve, it winds dorsally 

 around the mid-brain to the sulcus lateralis, where it bifurcates 

 into a medial and a lateral branch (Fig. 9). The medial branch 

 continues along the trochlear nerve in the groove between the 

 cerebellum and the mid-brain almost to the median line ; and then, 

 bending backward, runs along the superior worm of the cere- 

 bellum to its posterior extremity. It distributes branches to 

 the geniculate bodies, corpora quadrigemina, tela chorioidea 



Fig. 14. Median section of embryonic brain of the third month. 

 (McMurrich after His.) 



I. Myelencephalon. II. Metencephalon: i, Pons, 2, Cerebellum, in. Isthmus rhomb- 

 encephali. IV. Mesencephalon: i, Pedunculi, 2, Corpora quadrigemina. V. Diencephalon: 

 I, Pars mammillaris hypothalami, 2, Thalamus, 3, Epithalamus. VI. Telencephalon: I, Pars 

 optica hypothalami, 2, Corpus striatum, 3, Rhinencephalon, 4, Neopallium. 



ventriculi tertii and posterior surface of the pons, besides the 

 vermis superior cerebelli and the medial part of the superior 

 surface of the hemisphere. The lateral branch of the superior 

 cerebellar artery passes from its point of origin near the sulcus 

 lateralis of the mid-brain onto the superior surface of the cere- 

 bellum. It runs backward a half-inch from the border of that 

 surface, giving off collaterals along its course. The lateral branch, 

 together with the medial, supplies the superior cerebellar surface 

 almost as far back as the horizontal sulcus of the cerebellum, 

 along which the superior cerebellar artery anastomoses with both 

 the inferior cerebellar arteries. 



