232 



ABNORMAL ANATOMY OF THE LYMPHATIC SYSTEM. 



follow the course of the vein over the digastric 

 and stylo-hyoid muscles, where it meets 

 with lymphatic glands which it enters ; the 

 posterior group accompanies the occipital and 

 posterior auricular veins, traverses the glands 

 behind the mastoid process, and afterwards 

 those situated at the back and upper part of 

 the neck. The facial lymphatics, like the facial 

 veins, receive branches from the forehead and 

 eyelids, pass fiom the inner canthus of the eye 

 along the side of the nose and over the bucci- 

 nator muscle, where they meet with one or two 

 small glands ; they then gain the anterior edge 

 of the masseter, from whence they pass be- 

 low the margin of the jaw, to traverse the 

 glands there situated. These three groups of 

 vessels communicate freely with each other 

 in the cervical glands, and are joined by some 

 of the deep-seated lymphatics. These latter 

 may be divided into those of the cranium 

 and those of the face ; the former as well as 

 the lymphatics of the interior of the orbit are 

 not sufficiently known to admit of our stating 

 the exact course which they take. Fohmann 

 and Mascagni both conceive that they have 

 discovered the lymphatics of the brain and its 

 membranes and have had them delineated in 

 their published plates ; but they differ so ma- 

 terially from each other, and their descriptions 

 are so far from satisfactory that we must be 

 content to say that we are ignorant not only of 

 the course they take but even of their existence. 

 Fohmann represents them to be very large and 

 numerous, situated principally between the 

 arachnoid membrane and pia mater, while 

 Mascagni figures them on the pia mater as 

 exceedingly small and as accompanying some 

 of the veins ; others are also depicted as asso- 

 ciated with the meningeal vessels ; the trunks 

 of these vessels are supposed to descend with 

 the carotid, vertebral, and meningeal arteries 

 and with the internal jugular veins; while 

 Fohmann throws out a hint that they may ter- 

 minate in the venous system within the cra- 

 nium. 



The deep-seated lymphatics of the face are 

 associated with the bloodvessels; those accom- 

 panying the internal maxillary arteries enter 

 the gland or glands in the substance of the pa- 

 rotid, and join the temporal lymphatics. The 

 rest accompanying their bloodvessels reach the 

 upper cervical glands, and communicate freely 

 with the superficial lymphatics already traced 

 to the same glands ; the further progress of the 

 lymphatics in the neck is regulated by the 

 position of the glands, which it will be re- 

 membered form two groups, one situated be- 

 tween the stern o-mastoid muscle and the 

 trachea, and associated more with the internal 

 jugular vein, the other located in the cellular 

 interval between the sterno-mastoid and tra- 

 pezius muscles in the neighbourhood of the 

 external jugular. The former receives the lym- 

 phatics from the tongue, pharynx, and larynx, 

 and lower down from the thyroid gland, 

 trachea, and oesophagus; while the latter col- 

 lects them from the muscles of the posterior 

 region of the neck and of the shoulder. The 

 and efferent vessels of these two 



series of glands have frequent communica- 

 tions with each other. At the root of the neck 

 they unite freely with the lymphatics emerging 

 from the chest and with those of the upper 

 extremities, until ultimately one large vessel is 

 formed on either side, which receives the con- 

 tents of the whole, and which terminates either 

 by opening separately into the internal jugular 

 vein close to the entrance of the lymphatic 

 trunk, or into that trunk itself. 



(S. Lane.) 



LYMPHATIC SYSTEM, ABNORMAL 

 ANATOMY. The congenital variations from 

 the normal distribution of the lymphatic system 

 which have naturally most attracted attention 

 are those of the thoracic duct, or of the right 

 lymphatic trunk ; the remainder of the system 

 lying too minute for general investigation, and 

 the mode of its examination being within the 

 scope of only a few. 



The thoracic duct frequently varies as to the 

 precise point at which it opens into the venous 

 system, sometimes opening into the subclavian 

 vein, at others into the jugular. A very 

 striking departure of it from its usual arrange- 

 ment is when it is found opening into the veins 

 on the right side, just as it ordinarily does on 

 the left. I saw an instance of tin's during 

 the winter of 1834, in the body of a child dis- 

 sected by Mr. Skey. The duct followed its 

 usual course as high as the fifth dorsal vertebra ; 

 it then inclined to the right side, and opened 

 into the angle between the right jugular and 

 subclavian veins. It was remarkable that in 

 this subject the right subclavian artery was 

 abnormal in its mode of origin ; it arose from 

 the extreme left portion of the arch of the aorta, 

 and passed to its destination behind the trachea 

 and oesophagus. A similar transposition of the 

 thoracic duct occurs in cases of general trans- 

 position of the viscera. 



The thoracic ducts have been found some- 

 times both terminating on the same side, some- 

 times on opposite sides. It has also been 

 found dividing into two large trunks which pass 

 upwards parallel to each other for a consider- 

 able distance, and then unite again. Varieties 

 have been observed as regards its mode of 

 opening into the jugular and subclavian veins. 

 Instead of terminating as a single trunk, it has 

 been found to subdivide into two or three 

 branches, which open separately into the sub- 

 clavian or jugular veins. At its termination 

 the duct experiences generally some degree of 

 dilatation in some instances I have seen this 

 so considerable as to have the appearance of an 

 aneurismal enlargement. The duct has like- 

 wise been found to empty itself into ftie vena 

 azygos. In the pig, according to Panizza, a 

 communication between the duct and this vein 

 is constant and normal. 



The varieties in the course and distribution 

 of the lymphatic vessels and in the number 

 and position of the glands are doubtless as 

 numerous as those of the veins. 



The diseased states of this system may be 

 examined, first, as regards the lymphatic and 

 lacteal vessels ; secondly, with reference to the 



