ARTERIES 73 



hippocampus major, corpus fimbriatum, and choroid 

 plexus. 



THE BASILAR ARTERY : formed by union of the two ver- 

 tebral arteries. Extent, from lower to upper border of pons, 

 there dividing into posterior cerebrals. 



Branches : 



Transverse (4 or 6) : twigs to supply pons and internal 

 auditory, an offset to internal ear, with auditory nerve. 



Anterior inferior cerebellar : backwards to anterior part of 

 inferior surface of cerebellum ; anas, posterior inferior cere- 

 bellar of vertebral. 



Superior cerebellar: arises near termination, to upper 

 surface of cerebellum, winding round crus cerebri behind 

 3rd nerve ; anas, opposite fellow, inferior cerebellar. 



Posterior cerebral (2) : one on each side, terminal of basilar, 

 winds backwards round crus in front of 3rd nerve, passes 

 upwards to under surface of posterior cerebral lobes, joined 

 near crus by posterior communicating, and gives off : Postero- 

 median to posterior perforated spot ; Posterior choroid to choroid 

 plexus through transverse fissure ; Postero-lateral to optic 

 thalamus ; Cortical branches : temporal, calcarine, parieto- 

 occipital ; anas, anterior and middle cerebral. 



CIRCLE OF WILLIS : a name given to the anastomoses 

 between the vertebral and internal carotid arteries at base of 

 brain. The internal carotid sends forward the anterior 

 cerebrals, which are connected by the anterior communi- 

 cating. The basilar sends forwards the posterior cerebrals, 

 which are joined to the carotid by the posterior communicating 

 arteries. 



ARTERIES OF UPPER LIMB. 



THE AXILLARY ARTERY. 



Extent. From outer border of ist rib to lower border of 

 teres major insertion. Divided into three parts : 



IST PART. Extent. From outer border of ist rib to upper 

 border of pectoralis minor. 



Relations. In front. Pectoralis major, costo-coracoid mem- 

 brane, cephalic vein, external anterior thoracic nerve, and 

 branches of acromio-thoracic artery and vein. 



Behind, ist intercostal space and muscle, ist serration of 

 serratus magnus, posterior thoracic nerve. 



Inner side. Internal anterior thoracic nerve and axillarj 

 vein. Outer side. Brachial plexus. 



