THE ANTERIOR VENA CAVA. 609 



ficial and deep temporal veins, which have their principal roots in these 

 confluents. 



The subsphenoidal confluents extend on the sides of the body of the 

 sphenoid bone and the basilar process, from the base of the subsphenoidal 

 process to the condyloid fossa, by concurring in the obturation or closing 

 of the occipito-spheno-temporal hiatus. They open at their middle portion 

 into the corresponding cavernous sinus, by an oval aperture which the in- 

 ternal carotid artery traverses in penetrating into the cranium. The anterior 

 extremity terminates in a cul-de-sac. Posteriorly, they communicate through 

 the condyloid foramina with the occipito-atloid sinuses. The vessels which 

 carry off the blood from these confluents are the pterygoid veins, and the 

 anterior root of the occipital vein. We already know that the posterior 

 branch of the latter vessel removes the blood directly into the occipito-atloid 

 sinuses. 



b. The emergent veins of the spinal sinuses present a more simple dis- 

 position. At each intervertebral space arise several branches, which more 

 particularly make their exit by the intervertebral foramina to join the 

 neighbouring veins ; in the cervical region, the vertebral veins serve as a 

 receptacle in this way for the venous branches emanating from the spinal 

 sinuses ; in the dorsal region, it is the spinal branches of the intercostals ; 

 in the loins, the analogous branches of the lumbar veins ; . and in the sacral 

 region, the lateral sacral vein. 



AXILLARY VEINS. 



A general confluent of all the veins of the thoracic limb, and of some 

 from the trunk, the axillary vein commences beneath the scapulo-humeral 

 articulation, towards the terminal extremity of the corresponding arterial 

 trunk, accompanying the latter to the entrance of the chest, and joining the 

 confluent of the jugulars to constitute, with these two vessels, the inferior 

 vena cava (293, 18). 



In studying, from their origin to their termination, the numerous 

 branches which concur in the formation of this venous trunk, we re- 

 cognise : 



1. That they form in the foot a very rich network, from which proceed 

 the digital veins, satellite vessels of the homonymous arteries. 



2. That to these digital veins, which are united in an arch above the 

 large sesamoids, succeed three metacarpal branches or collaterals of the 

 cannon: two superficials, placed on each side of the flexor tendons, and a 

 profound (or deep) vein, situated underneath the suspensory ligament, along 

 with the interosseous arteries. 



3. That the metacarpal veins also open into each other, in the superior 

 and posterior region of the carpus, to form, on again separating, two groups 

 of antibrachial veins : one group comprising the ulnar and the posterior or 

 internal radials, which accompany the arteries of the same name ; the other, 

 constituted by a single subcutaneous branch, the median vein, which receives 

 at its superior extremity the anterior superficial radial vein. 



4. That at the ulnar articulation, these two groups of antibrachial veins 

 join the satellite vessel of the anterior radial artery, and communicate by a 

 very complicated system of anastomoses, from which results a principal 

 trunk, the humeral vein. 



5. That the humeral vein, after receiving on its course several muscular 



