THE VEINS 755 



great cardiac vein ascends in the left longitudinal groove of the heart to the coronary 

 groove, in which it courses to the diaphragmatic surface. Here it is joined by one 

 or two lesser cardiac veins, which are satellites of the right coronary artery, thus 

 forming the coronary sinus. There is commonly a vein in the intermediate groove 

 which joins the great cardiac vein. 



The anterior vena cava (Figs. 613, 614) is formed by the junction of short right 

 and left brachiocephalic veins, and each of the latter results from the confluence 

 of jugular and brachial veins. 



The vena azygos (Fig. 613) is continuous behind with the first lumbar vein; it 

 resembles that of the horse, and receives at the ninth or tenth thoracic vertebra a 

 vena hemiazygos. 



Two jugular veins are present on each side. The external jugular vein is the 

 chief vein of the neck; it is formed by the union of external and internal maxillary 

 veins at the posterior border of the mandibular gland. The two external jugulars 

 are commonly united by a transverse branch below the cricoid cartilage. Each 

 passes along the neck on the sterno-cephalicus, covered only by the skin and cu- 

 taneous muscle, dips under the cleido-cervicalis, and joins the internal jugular. 

 The internal jugular vein is the satellite of the common carotid artery. It results 

 usually from the junction of laryngeal and thyroid veins, but in some cases it is 

 formed by the confluence of the ventral cerebral and occipital veins. 



The external maxillary vein arises on the lateral nasal region by the junction 

 of the dorsal nasal vein with the angularis oculi. Near the infraorbital foramen it 

 receives the lateral nasal vein, and a little lower the sXiperior labial. In its course 

 along the anterior border of the masseter it receives the vena reflexa, which arises 

 in the pterygo-palatine fossa by the junction of infraorbital, sphenopalatine, and 

 palatine radicles, together with a branch from the cavernous sinus. At the ventral 

 border of the mandible it is joined by the inferior labial vein, which receives the 

 buccinator vein. The lingual vein is connected with its fellow by a superficial 

 transverse branch at the insertion of the sterno-hyoidei. The sublingual and 

 submental veins terminate in a variable manner, but often form a common trunk 

 which joins the lingual. 



The internal maxillary vein arises from the pterygoid plexus, formed chiefiy 

 by dorsal lingual, inferior alveolar, deep temporal, pterygoid, and meningeal tribu- 

 taries. It receives the dorsal cerebral, auricular, superficial temporal, transverse 

 facial, and masseteric veins, and often a trunk formed by the union of the ventral 

 cerebral and occipital veins. 



The brachial and radial veins are satellites of the arteries. 



The ulnar vein is usually double. It unites below the carpus with a branch of 

 the interosseous vein to form the superficial venous arch. 



The cephalic vein accompanies the ulnar artery in the forearm and joins the 

 superficial venous arch below. 



The accessory cephalic vein arises from the union of three dorsal metacarpal 

 veins. It joins the cephalic vein about the middle of the forearm. 



There are three short volar metacarpal veins which open into the superficial 

 venous arch. They are formed above the metacarpo-phalangeal joints by the 

 junction of the volar digital veins, of which there are two for each of the chief 

 digits. The volar vein of the first digit joins the superficial venous arch. 



Each of the chief digits has two dorsal digital veins, while the first digit has one. 



The portal veia (Fig. 625) is formed by the union of a common intestinal or 

 mesenteric vein mth the gastro-splenic vein. It receives the gastro-duodenal vein. 

 The intestinal trunk is formed in the mesentery by the confluence of veins from 

 the jejunum; it receives an ileo-caeco-colic vein. 



The posterior vena cava, its collateral affluents, and common iliac radicles 

 present no special features of importance. 



