VEIN. 



the poRerior condyloid foramina. The vein* of the orbit 

 alfo conllitute a communication between thefe two fets of 

 veins, as they are connected on one fide with the facial 

 veflels, and on the other with the cavernous finus. 



It appears from the preceding deicription , that all the finufes 

 end, either mediately or immediately, in the right and left 

 lateral, and confequently that all the blood conveyed to the 

 brain is returned by thefe veflels. Having pafled the fora- 

 men lacerum, the tube is called the internal jugular vein ; it 

 fwells out into a dilatation received into the foda jugularis 

 of the temporal bone, defcends perpendicularly along the 

 neck, in company with, and on the outfide of the internal 

 carotid firil, and afterwards of the common carotid artery, 

 and of the par vagum, with which parts it is enclofed in a 

 common cellular (heath. Juft behind tha anterior extremity 

 of the firll rib it ends, by joining at a right angle the lub- 

 clavian vein. The internal jugular is a very large vein ; 

 when diftended in the living fubjeft, or by injedlion after 

 death, it is nearly as large as the thumb. It receives the 

 following veins; viz. the pharyngeal, the Ungual, the com- 

 mon trunk, formed by the union of the anterior and pof- 

 terior facial, the fuperior and middle thyroid. 



The external or fuperficial jugular vein is formed by 

 two or three principal trunks, and by fmaller branches, 

 which form a kind of venous plexus on the fide of the 

 neck, covered by the (kin and by the latiffimus colli. Thefe 

 trunks are the occipitalis fuperficialls, which commences, in 

 company with the occipital artery, from the integuments of 

 the back of the head, and receives branches from the mufcles 

 of the neck ; tranlverfa colli, which accompanies the artery 

 of the fame name : deep-feated veins of the cervical mufcles ; 

 fubculaneous veins towards the front of the neck ; and 

 fmaller twigs from the fterno-maftoideus and lymphatic 

 glands. The trunk terminates at the angle of union of the 

 internal jugular and fubclavian, or in the fubclavian itfelf. 



For the veins of the neck, fee Walter's plates in the 

 Dbfervat. Anat. already quoted. 



yeins of the Upper Extremities The arteries are every 



where accompanied by correiponding veins, which lie clofe 

 to them, and are generally double, one on each fide. Thefe 

 it is not neceflary to defcribe. In addition to thefe, which 

 may be called the deep-feated, there is a cutaneous fet of 

 veins in the fingers, fore-arm, and ai-m, forming large 

 trunks placed merely under the fltin, not accompanied by 

 any arteries. Both the deep-feated and cutaneous veins 

 end in a fiiigle large trunk, the axillary, which accompanies 

 the artery of the fame name. 



The fuperficial veins of the fore-arm lie between the (l<in 

 and the fafcia, and form a venous net-work, compofed of 

 larger and fmaller branches, over the whole limb. There 

 is great variety in the fize and arrangement of the trunks, 

 which, however, are regular and conftant in the arm. The 

 digital veins run into trunks at the backs of the fingers, 

 completely covering them after fuccefsful injeftion ; they 

 form a plexus (dorfalis manus) on the back of the hand, 

 from which a large trunk (cubitahs interna, or ulnaris fuper- 

 ficiahs) or two, with fmaller ramifications, run in the 

 courfe of the ulna to the elbow. It palTes over the tendon 

 of the biceps, and affumes the name of bafihc vein ; afcends 

 along the arm, on the inner edge of that mufcle, in com- 

 pany with the brachial veflels, and enters the axilla, where 

 it ends in the axillary vein. 



A large vein on the back of the hand, arifing from the 

 little finger, was called by the ancients falvatella. 



A venous plexus arifes from the thumb, of which the 

 largeft branch is fometimes called cephalica poUicis ; this 

 Vol. XXXVl. 



plexus, containiag one or two larger trunks, (radialis ex- 

 terna, or cephalica minor, ) is continued along the radial fide 

 of the fore-arm to the bend of the elbow, where it divides 

 into two branches ; the largeft, under the name of median 

 vein, pafles obhquely in front of the joint to join the bafihc 

 vein ; the other is called the cephahc, (cephahca major,) 

 afcends on the outer edge of the biceps, runs in the cel- 

 lular interval between the peftoralis major and deltoid to 

 the edge of the clavicle, then dips under the bone, and ends 

 in the axillary vein. 



There is confiderable variety in the median vein, which 

 is fometimes merely an oblique communication between the 

 bafilic and cephalic : in other inftances, a large branch 

 comes from the middle of the fore-arm, (mediana comm.unis,) 

 and divides at the elbow into two trunks, which feparate 

 like the branches of the letter V, and join, one the bafihc, 

 and one the cephalic. Thefe branches are then called vena 

 mediana bafilica, and mediana cephalica. There is always 

 a large communication at the elbow, between this median 

 vein and the radial and ulnar veins. 



The axillary trunk, in which all the veins of the upper 

 extremity end, is placed in front of its correfponding artery, 

 on the fide and anterior part of the cheft ; paffes in front 

 of the anterior fcalenus mufcle. then taking the name of 

 fubclavian, and ends at the tternal extremity of the firll rib, 

 by joining the internal jugular at a right angle. In this 

 angle the thoracic duft ends behind, on the left fide ; and 

 the minor trunk in front, on the right fide. 



For reprefentations of the veins of the upper extremity, 

 fee Camper, Demonftrationes Anatomico-Pathologicas, lib.i- 

 Khnt de Nervis Brachii. 



The axillary trunk receives the fuperior and inferior 

 thoracic veins, the external and internal fcapular, the dorfalis 

 fcapulse, the vertebral, and the fuperior intercoftal vein. 



The trunk of the latter accompanies its correfponding 

 artery in the tranfverfe proceffes of the cervical vertebrae, 

 commencing about the foramen magnum, and receiving 

 numerous branches, of which the moll remarkable are from 

 a large plexus of veins lying dole on the vertebrx before 

 and behind, and connedled with the tranfverfa colli, the 

 occipital, and the internal jugular veins, from the finufes of 

 the medulla fpinahs in the neck, (circuh venoii cervicales 

 medullas fpinahs), and communicating with the cerebral 

 veins, at the foram.en magnum. The vertebral and fuperior 

 intercoftal veins end in that part of the trunk called fub- 

 clavian. 



The right fuperior intercoftal is fometimes deficient ; that 

 is, the veins of the two or three fuperior intercoftal intervals, 

 inftead of uniting into a feparate trunk, join the vena 

 azygos. The left is always a confiderable vein, formed by 

 the veins belonging to the five or fix fuperior intervals, 

 which join into a trunk afcending on the left fide of the 

 vertebral column, receiving the left bronchial vein, and fome 

 other fmall branches. 



The fubclavian vein, having received the internal jugular, 

 defcends on the right fide almoft perpendicularly, and on 

 the right of the arteria innominata, receives the internal 

 mammary vein, and very foon receives the left fubclavian at a 

 right angle. It now takes the name of fuperior or defcend- 

 ing vena cava, continues its courfe in the fame dircftion, 

 receives the vena azygos from behind, and after a farther 

 perpendicular defcent of about an inch, having penetrated 

 the pericardium, terminates in the right auricle. 



The left fubclavian vein crolTes the cheR, immediately 



behind the upper edge of the firft bone of the fternum, 



and in front of the trachea and primary branches of the 



4 S aortic 



