384 THE BRAIN 



Rami ad Pontem. The pontine branches are numerous 

 slender twigs which run, laterally, on the surface of the pons 

 before they enter its substance. 



Arteria Auditiva Interna. The internal auditory artery 

 will be seen amongst the pontine branches. It accompanies 

 the acoustic nerve into the internal acoustic meatus, and is 

 distributed to the internal ear. 



Arteria Cerebelli Inferior Anterior. The anterior inferior 

 cerebellar artery inclines postero-laterally to reach the anterior 

 part of the inferior surface of the cerebellum. 



Arteria Cerebelli Superior. The superior cerebellar artery, 

 on each side, is a large vessel which springs from the basilar 

 close to its termination. It winds laterally and backwards, 

 round the corresponding pedunculus cerebri, along the upper 

 border of the pons, to the upper surface of the cerebellum, 

 where its terminal branches ramify before entering the grey 

 matter. 



Arteria Cerebri Posterior. Immediately beyond the origin 

 of the two superior cerebellar arteries the basilar artery 

 bifurcates into the two posterior cerebral arteries, which 

 diverge from each other and curve laterally and backwards 

 round the mesencephalon. Then they run backwards towards 

 the inferior surface of the splenium of the corpus callosum. 

 In the first part of its course each posterior cerebral artery lies 

 deeply, in the interval between the corresponding pedunculus 

 cerebri and the hippocampal gyrus ; then it enters the cal- 

 carine fissure, and ends, in the fissure, by dividing into two 

 terminal branches, viz., the calcarine and the parieto-occipital 

 (Figs. 146, 147). 



The oculo-motor nerve passes forwards in the interval 

 between the posterior cerebral and the superior cerebellar 

 arteries, close to the place where they arise from the basilar ; 

 and the small trochlear nerve winds round the pedunculus 

 cerebri below the posterior cerebral artery. 



The following branches spring from each posterior 

 cerebral artery : 



f Postero-median. 

 Central or basal -j Postero-lateral. 



Posterior chorioidal. 



( Temporal. 



Cortical \ Calcarine. 



Parieto-occipital. 



The postero- median central arteries arise close to the origin of the parent 

 trunk. They proceed upwards, in the interval between the pedunculi cerebri, 

 and, after piercing the substantia perforata posterior (O.T. posterior per- 



