HEAD AND ANTERIOR CERVICAL STRUCTURES. 49 



Dissection of the Brain. 



Before beginning the dissection of the brain, the student should read the chapter on the 



mode of development "Neurology," 708-9-10. (692-3-4) 



THE BRAIN. 



The Arachnoid and Pia Mater will now be considered. 



The arachnoid, 715-16. (699-700) 

 Pacchionian glands. 



Structure of a Pacchionian body, 718. (702) . 



Subarachnoid tissue, 716-17. (700-1) 

 Subarachnoid spaces : 



Cisterna magna. 



Cisterna pontis. 

 Pia Mater, 717. (701) 

 Lymphatics of the Brain and Spinal Cord, 717-18. (701-2) 



Subarachnoid space. 

 Cerebro-spinal fluid. 



Carefully remove the membranes from the surface of the brain. Beginning at the base, the arteries 

 should be carefully exposed and traced as far as possible without injury to the brain substance. The 

 main trunks can be followed, the terminal distribution of the branches will be somewhat developed 

 during the process of the dissection. The description of the branches should be read at this time and 

 can be reviewed later as the vessels are exposed. 



Encephalon or brain, 718. (702) 

 Cerebrum. Mesencephalon. 

 Cerebellum. Peduncles or crura. 



Gray matter. White matter. 



Internal carotid. 



Intercranial portion, 529. (520) 



Anterior cerebral. Anterior communicating artery, 534. (524-5) 

 Branches of the anterior cerebral : 

 Communicating : 



Anterior communicating. 

 Antero median branches. 

 Ganglionic, or central : 

 Antero-median group. 

 Commissural. 



The hemispherical, or cortical branches: 

 Orbital. 



Margino-frontal. 

 Calloso-marginal. 

 Quadrate. 



Middle cerebral artery, 534-5. (525) 

 Branches of the middle cerebral : 

 Ganglionic, or central : 

 Caudate. 

 Antero-lateral. 

 Lenticulo-striate. 



Hemispherical, or cortical branches : 

 Inferior, or orbito-frontal. 

 Ascending frontal. 

 Parietal. 

 Parieto-temporal. 



Posterior communicating artery, 533. (524) 

 Branches : Uncinate. 



Middle thalmic. 

 Anterior choroid, 533-4. (524) 



