28 



APPLIED ANATOMY. 



in the longitudinal fissure on the corpus callosum, giving branches to the frontal and 

 parietal lobes, and finally anastomoses at the posterior end of the corpus callosum 

 with the posterior cerebral. This shows the wide extent of brain tissue on the medial 

 surface of the brain which would be affected by the blocking of this vessel by an 

 embolus. 



The terminal branches of the anterior cerebral spread laterally over the surface 

 of the brain (Fig. 32) outward from the longitudinal fissure for a short distance, 

 about 2 cm. As it crosses the anterior perforated space, it gives off the antero- 

 median perforating (ganglionic) arteries which pierce the lamina cinerea to supply 

 the anterior portion of the caudate nucleus above. 



Middle Cerebral Artery, The middle cerebral artery passes upward and 

 outward in the fissure of Sylvius, dividing, when opposite the island of Reil, into the 

 branches which supply the cortex of the brain (see Fig. 32). On its way toward 



Degenerative area 

 Corpus callosum 



Nucleus caudatus 

 Apoplectic area 

 Internal capsule 



Nucleus lentiformis 



Crura cerebri 



Pons 



! ( Medulla oblongata 



Decussation 



' 



FIG. 34. Showing the degenerative and apoplectic areas of the brain and the course pursued by the motor 

 fibres from the cortex, through the internal capsule, crura, pons, and medulla to the decussation, where they 

 cross the median line to supply the opposite side of the body. 



the island of Reil, at the commencement of the fissure of Sylvius, many small straight 

 branches enter the brain substance to supply the basal ganglia. Two or three supply 

 the caudate nucleus, others, called the anterolateral perforating (ganglionic), enter 

 the anterior perforated space to supply the lenticulostriate ganglion and the anterior 

 portion of the thalamus. One of the largest of these arteries, the lenticulostriate, has 

 been called the artery of cerebral hemorrhage , by Charcot, on account of the frequency 

 with which it is found ruptured in cases of apoplexy (Fig. 33). 



Anterior Choroid. The anterior choroid artery comes sometimes from the 

 internal carotid and sometimes from the middle cerebral. It passes backward and 

 outward on the optic tract and cms cerebri and enters the transverse fissure at the 

 descending horn of the lateral ventricle. It 'ends in the choroid plexus (see Fig. 33). 



Posterior Cerebral Artery. The posterior cerebral artery passes outward over 

 the crus cerebri, just above the pons, to the under surface of the posterior portion of 

 the cerebral hemisphere. Before it receives the posterior communicating artery it gives 

 off the posteromedian perforating (ganglionic) arteries, which enter the posterior 

 perforated space to supply the thalamus and third ventricle. Just beyond the poste- 



