ANATOMY IN A NUTSHELL. 



359 



LESSON cm. 



The Medulla Oblongata is about one and one-half inches long and three- 

 fourths of an inch wide and one-half of an inch antero-posteriorily. It extends 

 from the foramen magnum inferiorly to the pons superiority. It is the smallest 

 part of the main divisions of the brain but the largest from a physiological 

 standpoint. It has five main centers in it, viz., (1) Respiratory, (2) Cardio- 

 inhibitory, (3) Vasomotor, (4) Diabetic, and (5) Salivary. (Plate CLXXXV1I). 



PLATE CLXXIX. 



OLFACTORY BULB 



OPTIC NERVE 

 OPTIC COMMISSURE 



|NT. CAROTID ARTERY 

 THIRD N 

 FOURTH N 

 SIXTH N 

 AUDITORY ARTERY, 

 .AUDITORY AND FACIAL 

 SUPERIOR PETROSAL 

 INFERIOR PETROSAL 



STRAIGHT SINUS. 



TORCULAR HEROPHlLl 



>jPERI0R LONGITUDINAL SINUS. 



OPHTHALMIC VEIN- 



CAVERNOUS SINUS. 



OPHTHALMIC DIVISION 

 OF FIFTH N 



BASILAR A 



VERTEBRAL A. 

 ANTERIOR SPINAL A. 

 GLOSSOPHARYNGEAL 



AND PNEUMOGASTRIC 



HYPOGLOSSAL 



SPINAL ACCESSORY 

 OCCIPITAL SINUS 



RIGHT LATERAL SINUS, 



Sinuses at the Base of the Brain. 



It is gray on the outer side and white on the inner. Its posterior SUR- 

 FACE makes the lower part of the anterior boundary or the floor of the fourth 

 ventricle. Its anterior surface rests upon the basilar process of theoccipital 

 bone. In the median line of the anterior surface is the antero-median fissure 

 which is continuous with the antero-median fissure of the cord. On each side 

 of this fissure there is a pyramid. This pyramid has fibres next to the fissure 

 which are derived from the crossed pyramidal tracts after they push the gray 

 matter of the anterior horn of the cord superficially. Next to this it has the 

 fibres of the direct pyramidal tract. External to the pyramid we have the 

 olivary body superiority and the lateral tract infcriorily. This olivary body has 



