THE LYMPHATICS OF THE UPPER EXTREMITY. 965 



nodes it perforates the costo-coracoid membrane and terminates in one of the 

 subclavicular nodes or, more rarely, follows the course of the jugulo-cephalic vein 

 over the clavicle and terminates in one of the lower inferior deep cervical nodes. 

 From the net-work of the posterior surface of the brachium a number of small stems, 

 arise and pass obliquely upward, those lying towards the outer border of the arm 

 curving around it to join the outer main stems, while the inner ones partly join the 

 inner main stems and partly terminate in the subscapular nodes along with the vessels 

 from the posterior surface of the shoulder. 



The deep lymphatics of the arm are much less numerous than the super- 

 ficial ones and follow the courses of the main blood-vessels, usually corresponding in 

 number with the venae comites. They occur in company with the radial, ulnar, 

 anterior and posterior interosseous, and brachial vessels. 



The radial lymphatics are formed by the union of two stems, one of which follows 

 the course of the main stem of the artery from the deep palmar arch, while the other 

 accompanies the superficial volar artery from the superficial arch. They come 

 together, usually a short distance above the wrist-joint, to form two stems which pass 

 upward along the artery and may traverse one or two small and inconstant nodes. 

 They terminate by uniting with the ulnar stems to form the brachial lymphatics. 



The ulnar lymphatics are also formed by the union of two stems, which 

 accompany the deep and superficial branches of the ulnar artery. They accompany 

 the ulnar artery up the forearm, occasionally traversing one or two small nodes, and, 

 near their union with the radial stems below the bend of the elbow, they receive the 

 stems which accompany the anterior and posterior interosseous arteries. 



The brachial lymphatics are two in number and are formed by the union of the 

 radial and ulnar stems. They accompany the brachial artery, traversing three or 

 four nodes in their course and receiving the ef?erents of the epitrochlear nodes, or, 

 these failing, the inner stems of the forearm. They terminate in the brachial nodes 

 of the axillary plexus, especially in one which usually lies between the axillary vein 

 and the subscapular muscle. 



Practical Considerations. — The Lymph- Abdes of the Axilla and Upper 

 Extremity. — The palm has relatively few large lymphatics (as it has few superficial 

 nerves and blood-vessels) ; hence wounds of the fingers or of the dorsum of the 

 hand, where the lymphatics are of larger size, are more commonly followed by 

 lymphangitis than are wounds of the palm. Nodes are occasionally found along the 

 course of the arteries of the forearm and arm, but are inconstant and not of great 

 practical importance. One or two beneath the deep fascia on the flexor surface of 

 the elbow and on a level with the internal condyle or an inch or two above it, are less 

 variable and are sometimes palpably enlarged in syphilis at the time of the early 

 general adenopathy. 



The axillary nodes will be almost sufificiently described in relation to the 

 subject of mammary cancer (page 2035). Further reference to them will be found in 

 the description of the axilla (page 581). 



These nodes may be the primary seat of lympho-sarcoma, may be the subject of 

 tuberculous or syphilitic enlargement, and are constantly infected after septic wounds 

 of the hand, forearm, or arm, and less frequently from wounds in the remaining 

 areas which drain into them, viz., the cervical region over the trapezius muscle, the 

 dorsal region, the lumbar region as far down as the level of the iliac crest, the 

 abdominal region above the umbilicus, and the front and sides of the thoracic region. 

 Their progressive enlargement widens the axilla, renders it more shallow by pushing^ 

 its floor downward, makes the anterior fold prominent, and increases the space 

 between the outer border of the scapula and the thoracic wall. Axillary abscess 

 commonly originates in these nodes, consecutively to sepsis elsewhere, as in the 

 regions mentioned, or after shoulder-joint suppuration, or mammary infection, or 

 caries of an upper rib. Such an abscess will produce rapidly the same phenomena as 

 those caused by a growth. It may make its way behind the clavicle into the supra- 

 clavicular fossa by following the cords of the brachial plexus, or may gravitate down 

 the arm along the course of the vessels. It cannot come directly forward on account 

 of the pectoral muscles and clavi-pectoral fascia, or downward on account of the 



