ANATOMY IN A NUTSHELL. 



343 



The Assures or sulci of the brain are infoldings of the cortex and the more 

 numerous and deeper they are, the greater is the amount of the peripheral gray 

 substance. 



The gray matter of the brain which invests the cerebellum and cerebrum, 

 is also called the cortical substance, in distinction from the white or medullary 

 substance of the interior. There are several ganglia or collections of gray mat- 

 ter in the interior, as the corpora striata, the optic thalami, the optic 

 lobes or corpora quadrigemina,the corpora dentata of the cerebellum, and 

 the corpora olivaria of the medulla oblongata. There are two non-nerv- 

 ous structures connected with the brain, the conarium or epiphpsis cerebri 

 and the pituitary body or hypophysis cerebri. 



The principal fissures of the cerebrum are: (Plates CLXXV-CLXIX), 



(a) The longitudinal fissure which separates the two hemispheres. 



PLATE CLXIII. 



DUODENUM 



SEROUS COAT 



LONGITUDINAL MUSCULAR LAYER 



CIRCULAR MUSCULAR LAYER 



AREOLAR COAT 



MUCOUS COAT 



The Four Coats of the Stomach and the Pyloric Orifice. 



(b) The Sylvian fissure is the largest, deepest, and most constant of the 

 fissures of the brain. It has a short anterior and long posterior branch, the 

 latter separating the temporal from the parietal lobes. It has the middle cere- 

 bral artery in it, lesser wing of sphenoid and central lobe or isle of Reil. 



(c) The fissure of Rolando or central fissure is a deep sulcus separating 

 the frontal and parietal lobes of the cerebrum on each side. 



(d) Parieto-occipital fissure extends from the longitudinal fissure outwards 

 for about, one inch between the parietal and occipital lobes. 



(e) The transverse fissure is a crevice through which the invagination of 

 the pia mater is effected, it starts from the porta (foramen of Monro) nearly 

 to the distal end of the middle horn on each side. It is at the base of the brain. 

 It is also called choroid fissure. 



(f) Calloso -marginal fissure is nearly concentric with the callosal and also 

 with that of the margin of the hemisphere until a point above the hind end of 

 the callosum is reached, at which the fissure turns and runs upward and back- 

 ward to the upper border. 



