ANATOMY IN A NUTSHELL. 445 



are anterolateral ganglionic which passes to the corpus striatum, internal cap- 

 sule and optic thalamus; external and inferior frontal which pass to the third 

 frontal convolution; ascending frontal which passes to the ascending frontal 

 convolution; the ascending parietal which passes to the ascending parietal con- 

 volution; and parieto-sphenoidal which passes to the angular convolution and 

 the superior temporo-sphenoidal convolution, (c) The posterior commu- 

 nicating artery, (Plate CLXXIII) which runs backward and joins the pos- 

 terior cerebral artery. It sends postero-mediaD ganglionic branches which 

 pass through the posterior perforated space, the optic thalamus and wall of the 

 third ventricle, (d) Anterior choroid artery which runs backward into 

 the descending horn of the lateral ventricle. (Plate CLXXIII.) 



The circle of Willis is formed by seven arteries which make an enclosure 

 at the base of the brain just beneath the third ventricle. All the structures 

 in the floor of the third ventricle are in the circle of Willis except the tegmental 

 portion of the cms, and everything in the circle of Willis is in the floor of the 

 third ventricle except the optic commissure. The arteries that make this circl e 

 arc the two posterior cerebral from the basilar; the two anterior cerebral which 

 are branches of the internal carotid; the two posterior communicating and the 

 anterior communicating which is the shortest artery in the body and has upon 

 it ganglion of Ribes. 



The posterior cerebral which are branches of the basilar artery wind around 

 the cms cerebri to the under surface of the occipital lobe. Here it sends branches 



(a) TO THE UNCINATE LOBE, (b) TO THE CUNEATE LOBE, (c) TO THK TEMPORAL 



lobe. Xear its origin it receives the posterior communicating artery. The 

 postero-median ganglionic branches pass from the posterior cerebral through 

 the posterior perforated space to the walls of the third ventricle. A posterior 

 choroid branch conns from the posterior cerebral and passes to the velum in- 

 terpositum and choroid plexus. A postero-Iateral ganglionic branch comes 

 from the posterior cerebral ami passes to the optic thalamus. 



LESSON CXXXVII 



The Relations of the Entern kl Carotid Artery. 



Ix Front. — (1) Skin, (2) Superficial ami deep fascia, (3) Platysma, (4) 

 Sterno-mastoid, (5) Occipital artery, (0) Posterior auricular artery. (7) Hypo- 

 glossal nerve, (8) Parotid gland, (9) Stylo-glossus, (10) Stylo-pharyngetis. 

 (11) Glosso-pharyngeal nerve, (12) Pharyngeal branch of the pneumogastric. 



Behind. — (1) Rectus capitis amicus major. (2) Sympathetic, (•'>) Super- 

 ior laryngeal nerve. 



Externally. — (1) Internal jugular vein, (2) Pneumogastric nerve. 



Internally. — (1) Pharynx, (2) Superior laryngeal nerve. (3) Ascending 

 pharyngeal artery, (4) Tonsil. 



The Right subclavian artery arises from the innominate opposite the sterno- 

 clavicular articulation and passes upward and outward to the Scalenus anticus 

 muscle on the right side. The left Subclavian artery arises from the end of 

 the arch of the aorta and ascends to the Scalenus anticus muscle. The artery 



