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 superior 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 
buecinator 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 chiefly 
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 vein (Fig. 625) is formed by the union of a common intestinal or 
mesenteric vein with 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-cxeco-colic vein. 
The posterior vena cava, its collateral affluents, and common iliac radicles 
present no special features of importance. 
