THE SUBCLAYIAX YEIX. 4S» 



upper limb in which valves are constantly found. It extends, like the 

 corresponding artery, from the lower border of the axilla to the outer 

 margin of the first rib ; it is covered by the pectoral muscles and the 

 costo-coracoid membrane, and is placed to the inner side of the axillary 

 artery. It is continuous below with the basilic vein of the arm, either 

 alone or in conjunction with one of the deep brachial veins. 



Tribvitaries. — The axillary vein receives the subcutaneous veins of the arm, 

 ■viz. the basilic at its commencement, the cephalic towards its termination ; and 

 between these the companion veins of the brachial artery ; it is also joined by 

 the several veins corresponding- with the branches of the axillary artery, viz., 

 the two ctrcHmJ1e,v and the .siibftcajiulai- veins from the shoulder, the alar vein 

 from the axilla, and the inferior, siqwrior, and acromio-thoracie veins from the 

 side of the chest. 



SUBCLAVIAN VEIN. 



The suTjclaviaii vein is the continuation of the axillary, but is not 

 like it constantly provided with valves, although a pair may often be 

 found near its termination (Struthers, loc. cit.). It extends from the 

 outer margin of the first rib to the inner end of the clavicle, behind 

 which it terminates by joining with the internal jugular vein to form 

 the innominate or brachio-cephalic vein. The subclavian vein crosses 

 over the first rib and behind the clavicle, not reaching so high up in 

 the neck as the subclavian artery; it is covered by the clavicle, and by 

 the subclavius and sterno-raastoid muscles, and lies on a plane anterior 

 to the artery, from which, while resting on the rib, it is seioarated by 

 the scalenus anticus muscle and the phrenic nerve. 



Tribiitaries. — (ff) The external and anterior jugular veins open into the sub- 

 clavian vein on the outer side of the scalenus anticus muscle. 



[h^ The xertehral vein, commencing- in branches which proceed from the peri- 

 cranium and the deep mi;scles lying- behind the foramen magnum of the occipital 

 bone, passes outwards and do^\'nwards to reach the foramen in the transverse pro- 

 cess of the atlas. Through this foramen, and through the canal foi-med by the 

 corresponding- foramina of the other cervical vertebraB. the vein descends with the 

 vertebral artery. Emerg-ing at the foramen in the sixth vertebra, it runs forwards 

 and downwards to jom the subcla-vian vein close to its temrination : a small 

 branch sometimes descends through the foramen in the seventh vertebra, and 

 opens separately into the suljclavian. The vertebral vein is joined in its course 

 by several branches from the neighboiiring- muscles ; also, immediately before 

 its termination, b}^ a branch corresponding -with the deep cervical artery ; and in 

 the same situation by another branch of considerable size, which descends in 

 front of the bodies and transverse processes of the vertebra3 of the neck, and 

 may be termed the external vei-tebral vein. It communicates frequently with 

 the spinal veins in the neck, both those on the outer side, and those in the 

 interior of the spinal canal. 



Varieties.— The subcla\-ian vein has been seen to pass behind the scalenus 

 anticus muscle along with the artery (Henle). In another case the vein and 

 artery changed places with relation to the muscle. The vein has been seen 

 several times to pass between the subcla\-ius muscle and the clavicle (Luschka). 

 Instead of being the continuation of a single axillary vein, the subclavian vein 

 is sometimes made up by the union of two brachial veins (Henle) : or it may 

 receive as unusual branches a bronchial vein (Weber), or a superficialis colli 

 inferior vein (Hj-rtl). 



AZYGOS VEIN'S. 



The azygos veins are longitudinal vessels formed by the union of 

 the veins corresponding to the arteries of the intercostal spaces, and 



