Anatomical Observations on the Ending of the Human Thoracic Duct 1 NEIVO LUIZ ZORZETTO, WAGNER RIPARI, VALDEMAR DE FREITAS A N D GERALD0 SEULLNER Department of Morphology, School of Biology and Medicine, Botucatu 18600

S k Paulo, Brazil

ABSTRACT Fifty-one cadavers of human adults of both sexes were examined for the ramifications and site of opening of the cervical segment of the thoracic duct. It was found that the duct opened into veins of the neck through either one (84.31%) or two branches (15.69%).The most frequent site of opening was in the junction of the left internal jugular vein with the subclavian vein (18 individuals), but another frequent site (15individuals) was in the internal jugular vein. The duct opened at the angle formed by the internal jugular vein and the internal posterior jugular vein in five individuals, and a t a variety of the other locations in the remaining cadavers. These results are compared with the findings of previous investigators. studied cadaver, presenting a great morphologic variety in its opening into the venous system on the left side of the neck. Forty-three (84.31%) ducts ended with a single opening into the venous system (figs. 1, 4-6, 8 ) and eight ducts (15.69%)ended by two openings into the venous system (figs. 2, 3, 7). In the first group we saw that the end of the duct was simple (figs. 5,8), as it occurred in 35 cases; or it presented rather complex ramifications which joined in a common trunk before the junction with the cervical veins, as in eight cases (figs. 1, 4, 6). In two of the latter cases (fig. 4), the duct ended in lymph nodes of the left jugular lymphatic chain, and from these lymph nodes three branches started and joined into a common trunk to reach the angle formed by the external jugular vein and internal jugular vein. MATERIAL AND METHODS In the eight cases in which the duct had Fifty-one cadavers of adult Brazilians from double endings (figs. 2,3, 71, it was subdivided both sexes fixed in 10%formalin were used in into multiple channels with lymph nodes inthis study. terposed in a rather complex display before The cadavers were injected with colored they reunited into two branches which either latex-Neoprene (Dupont) through the "cister- opened into the same vein or into different na chyli." The thoracic duct and its related veins. structures were identified during gross neck In 20 of our 51 cases we observed that the dissection, and for a better a n d deeper final portion of the thoracic duct showed a visualization a Zeiss stereoscopic microscope dilatation with a n ampullar form, always was used. with a greater caliber than in any other duct

The lymphatic system is relatively little understood considering its importance for the normal physiology and physiopathology, and its significance for surgical procedures. The thoracic duct occupies a relevant position in the lymphatic system because of its opening into one or more of the large neck veins. Previous investigations on thoracic duct terminations include those of Parsons and Sargent ('091, Davis ('Xi), Idanov ('591, Shafiroff and Kau ('59), Rocca-Rossetti et al. ('61), Archimbaud et al. ('69) and Kinnaert ('73). Classical anatomy texts of Testut and Latarjet ('59), Llorca ('671, Chiarugi-Bucciante ('72) and Benninghoff-Goerttler ('60) also mention variations in thoracic duct endings. Our investigation revealed certain variations not previously recorded in the literature.

RESULTS

The thoracic duct was found in every J. MORPH., 153: 363-370

I Supported by FundaqBo de Amparo a Pesquisa do Estado de SBo Paulo, Brazil

363

364

N. L. ZORZETTO, W. RIPARI, V. DEFREITAS AND G. SEULLNER A bbreuiations

TD, Thoracic duct BCV, Brachiocephalic vein

IJV, Internal jugular vein SCV, Subclavian vein VV, Vertebral vein

EJV, External jugular vein SSV, Suprascapular vein

Fig 1 Multiple lymphoid channels (stippled) ending in a n ampullar dilatation of a thoracic duct that ended in the internal jugular vein Cross hatched structures are lymph nodes

Fig. 2 Thoracic duct ending by two branches, one joining the jugulosubclavian angle and the other the subclavian vein. An ampullar dilatation is present on only one of the branches.

VARIATIONS OF THE THORACIC DUCT IN MAN

365

Fig. 3 Thoracic duct ending by two branches, both in the internal jugular vein.

Fig, 4 Thoracic duct ending in lymph nodes of the cervical lymphatic chain, three branches from the lymphatic chain are into a single trunk that ends by an ampulla in the angle formed by internal jugular vein and external jugular vein.

Fig. 5 Single thoracic duct ending in the angle formed by internal jugular vein and vertebral vein. Cervical lymphatic vessels ending in the jugulo-subclavian angle independently of the thoracic duct.

366

N. L. ZORZE'ITO, W. RIPARI, V. DEFREITAS AND G. SEULLNER

Fig. 6 Thoracic duct with two branches that are reunited into a short trunk before it ends in the angle formed by internal jugular vein and suprascapular vein.

Fig, 7 Thoracic duct ending by two branches, one in the jugulo-subclavian angle and the other in the suprascapular vein, The latter is shown receiving numerous mediastinal, axillar and cervical lymphatic vessels.

Fig. 8 Single thoracic duct ending in a terminal ampulla t ha t receives vessels from cervical lymph nodes.

portion. I n 43 cases (84.31%) the left lymphatic jugular cervical trunk opened into the thoracic duct through one or multiple branches, and in eight cases i t opened into the veins of the left side of the neck. Sites of duct terminals in the cervical veins, by either one or two branches, are given in tables 1 and 2. DISCUSSION

According to literature data available the

final portion of the thoracic duct is extremely variable. The incidence of ducts ending by one channel in our study was found to be 84.31%. Archimbaud e t al. ('69) found single endings in 72.20%,Correia ('26) in 59.40%,Davis ('15) in 81.00%,Kinnaert ('73) in 78.70%,Parsons and Sargent ('09) in 77.50%,Rocca-Rossetti et al. ('61) in 85.70%,Shafiroff and Kau ('59) in 90.00% and Speranzini et al. ('72) in 65.30%. Different results were obtained only by

VARIATIONS OF THE THORACIC DUCT I N MAN TABLE 1

Sites of thoracic duct ending by only one branch Number of cases

Sites

~

Left jugulosubclavian angle Left internal jugular vein Angle of internal jugular vein with left posterior jugular vein Left subclavian vein Cervical lymphatic chain Left jugulovertebral angle Total

18 15 5 2

2 1

43

TABLE 2

Sites

of

thoracic duct ending by two branches Sites

Number of cases

Jugulosubclavian angle and left subclavian vein Jugulosubclavian angle and suprascapular vein Internal jugular vein and left subclavian vein Internal jugular vein and left brachiocephalic vein Internal jugular vein and suprascapular vein Total

Jdanov ('591, who found 27.00%of ducts ending by one channel. The incidence of our cases in which the duct showed multiple channels that joined in only one ending branch, found in eight cases (15.69%),was lower than that observed by Kinnaert ('73) who found 65.90%in 47 studied cases. Ducts t h a t ended by three branches were suggested by Archimbaud et al. ('69), Rocca-Rossetti e t al. ('61) and Tesauro ('661, but we found only cases with two ending branches in addition to those ending singly. The sites of ducts ending in the venous system, according to different authors, are represented in table 3. Our results show some differences with those of other authors. Thus, in our series, the most frequent site of duct ending was t h e jugulosubclavian angle (35.30%)in agreement with Rocca-Rossetti et al. ('61). Archimbaud et al. ('69) and Davis ('151, however, found the most common site of duct ending to be the left subclavian vein, and Jdanov ('59) found i t to be the left internal jugular vein. The second most frequent site for the ending of the thoracic duct in our series was the left internal jugular vein (29.42%),reported as the most frequent site by some other

367

authors. In 9.8%of our cases the duct ended in the angle of internal jugular vein with the posterior external jugular vein, and although this site was the third most frequent in our study it has not been mentioned by previous authors above. Archimbaud e t al. ('69), Davis ('151, Jdanov ('591, Kinnaert ('731, RoccaRossetti et al. ('611, and Shafiroff and Kau ('591, reported that the third most frequent site was the subclavian vein. In our series this site was observed in only 3.92%of the cases. We observed duct ending by two channels, respectively in the internal jugular vein and subclavian vein, only once, and Parsons and Sargent ('09) found this pattern of duct ending in three cases. We found the duct ending by two channels in the internal jugular vein and brachiocephalic vein only once in our study, and this pattern has not been previously reported. We observed the duct ending by two branches, one in the jugulosubclavian angle and the other in the subclavian vein, in 7.84%of our cases. Only Kinnaert ('731 among the other workers refers to this modality, which he observed in 8.5%of his cases. The entrance of single ducts into the angles formed by the internal jugular vein with the vertebral vein or with the suprascapular vein once in each modality in our study has not been described in previous literature. Likewise, ducts ending in the lymphatic cervical chain, seen in 3.92% of our series, have not been described elsewhere. Such ducts joined the venous system indirectly, because the channel that reached the angle formed by the internal jugular vein and the external jugular vein, (fig. 4) resulted from a reunion of three branches arising from the cervical lymph nodes in which the duct proper ended. In our series we have found no cases of ducts ending by only one branch in the brachiocephalic vein, as observed by Davis ('151, Jdanov ('59) and Shafiroff and Kau ('59). Neither did we find ducts ending in the internal jugular vein and jugulosubclavian angle, nor in the internal jugular vein or vertebral vein as observed by Davis ('15). Furthermore, we found no ducts ending in the transverse cervical vein, as described by Kinnaert ('73). Totalling t h e records of t h e different authors, we acknowledge that based on 339 observations of anatomical or surgical dissections the most frequent site of the duct terminal is the internal jugular vein, followed by the jugulosubclavian angle and thirdly by the subclavian vein. The other sites represent

368

N. L. ZORZETTO. W. RIPARI, V. DEFREITAS AND G. SEULLNER TABLE 3

Comparison of the sites of thoracic duct ending in the series of different authors -

Authors S1tea of

thoracic duct ending Internal jugular vein Jugulosubclavian angle Angle of internal jugular vein with external posterior jugular vein Subclavian vein Angle of internal jugular vein with vertebral vein Angle of internal jugular vein with suprascapular vein Brachiocephalic vein Internal jugular vein and jugulosubclavian angle Internal jugular vein and subclavian vein Internal jugular vein and vertebral vein Internal jugular vein and brachiocephalic vein Jugulosubclavian angle and suprascapular vein Jugulosubclavian angle and subclavian vein

Rocca-

Zorze tto

Sargent

Davis

Shafiroff and Kau

Jdanov

1'091

('15)

('591

1'59)

('61)

('691

1'731

1 (4.80) 5 (23.801

18 (60.00) 3 (10.001

48 (47.70) 35 (35.401

5 (35.80) 7 i50.00)

6 (16.70) 10 (27.80)

17 (36.20) 16 (34.10)

15 (29.42) 18 (35.30)

144 (42.49) 97 (28.621

-

-

-

-

-

-

12 (57.10)

7 (23.30)

9 (9.201

1 (7.10)

18 (50.001

8 (17.001

5 (9.80) 2

-

-

-

-

-

-

5 (1.48) 57 (16.82) 1 (0.29)

-

-

-

-

-

-

1 (4.80) 1 14.80)

2 (6.701

8 (7.701

-

-

-

-

1 (2.10)

-

Parsons and

Rossetti

Archimbaud et

al

Kinnaert

e t al Ithis study1 -

(3.92) 1 (1.96)

1 (1.96)

Total

1 I0 29) 11 (3.25) 2 (0.59)

-

-

-

-

-

-

-

-

-

-

1 (1.96)

1 (4.80)

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

-

4 (8.50)

Cervical lymphatic chain Internal jugular vein, subclavian vein and external jugular vein Internal jugular vein, jugulosubclavian angle and subclavian vein

-

-

-

-

-

-

1 (1.96) 1 (1.96) 4 (7.84) 2 13.92)

-

-

-

-

2 (5.50)

-

-

2 (0.59)

-

-

-

(7.10)

-

-

-

1 iO.29)

Transverse cervical vein

-

-

-

-

-

-

30

100

1 (2.10) 47

21

Total

i100.00)

~100.00i (100.001

1

14 (100.00

36

-

~100.001 i100.001

4

(1.18) 1 (0.29) 1 (0.29) 1

(0.29) 8 (2.36) 2 (0.59)

1

51

(0.29) 339

i100.00)

(100.001

' The values in parentheses indicate the percentage relative to the n u m b r of cases. only 12.07% of the total and may be considered variations. Ampullar dilatation in the duct ending was observed in 20 of our cases. Kinnaert ('73) studying the duct in vivo found it in ten patients. This author considered t h a t in a study done on cadavers, the dilatation is a n artifact resulting from the injection with colored material and that its presence in vivo depends on the rate of lymph flow, the pressure in the thoracic duct and the structure of the lymphovenous junction. Entrance of the left jugular lymphatic trunk into the thoracic duct, verified in 84.31%of our cases has been reported by a few previous authors.

LITERATURE CITED Archimbaud, J. P., V. Bansillon, J. Bernhardt, P. Bonnet and E. C. Saubier 1969 Quarante dissections du canal thoracique. Sa terminaison chez l'homme vivant. Lyon Mdical., 30: 211-214. Benninghoff, A,, and K. Goerttler 1960 Lehrbuch der Anatomie des Menschen. Vol. 2, sixth ed. Urban & Schwarzenber, Miichen, pp. 580-581. Chiarugi, G., and L. Bucciante 1972 Instituzioni di Anatomia dell 'Uomo. Vol. 11. Tenth ed. F. Vallardi, Milano, pp. 1031.1036, Correia, M. 1926 Le canal thoracique chez I'homme. Folia Anat., I: 1-20, Davis, H. K. 1915 A statistical study of the thoracic duct in man. Am. J. Anat., 17: 211-244. Jdanov, D. A. 1959 Anatomie du canal thoracique e t des principaux collecteurs lymphatiques d u tronc chez I'homme. Acta Anat., 37: 20-47.

VARIATIONS OF THE THORACIC DUCT IN MAN Kinnaert, P. 1973 Anatomical variations of the cervical portion of th e thoracic duct i n man. J. Anat., 115: 45-52. Llorca, F. 0. 1967 Anatomia Humana. Vol. 3. Third ed. Editorial Cientifico-Medica, Barcelona, pp. 265-275. Parsons, F. G.,and P. W. G. Sargent 1909 On the termination of the thoracic duct. The Lancet, l: 1773-1774. Rocca-Rossetti, S., R. Aresu and G. Liguori 1961 Ricerche sulla composizione della linfa umana. I. Anatomia chirurgica del dotto toracico a1 collo e tecnica del cateterismo. Rassegna Medica Sarda, 63: 651-656.

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Shafiroff, B. G. D., and G. Y.Kau 1959 Cannulation of the human thoracic lymph duct. Surgery, 45: 814-819. Speranzini, M.B.,A. C. Cordeiro, A. Widman, M. R. Oliveira and P. A. Toledo 1972 Ducto toracico: estudo anatomoradiologico de 59 casos. Rev. Paul. Med., 79: 1-16. Tesauro, N. 1966 Anatomical aspects of the thoracic duct after ligation. Bull. SOC.Inter. Chir., 25: 602-607. Testut, L., and A. Latarjet 1959 Tratado de Anatomia Humana. Vol. 2. Ninth ed. Salvat ed., S. A.Barcelona, pp. 522-530.