THE LYMPHATIC DRAINAGE OF THE HEART (A preliminary communication)

Transcription

1 THE LYMPHATIC DRAINAGE OF THE HEART (A preliminary communication) By L. R. SHORE, M.A., M.B., M.R.C.P. EXAMINATION of the literature shows that the accounts of the lymphatic system of the heart differ very widely, both of the glands into which lymph vessels drain from the heart and of the disposition of the main lymphatic collecting vessels themselves. I have studied the lymphatic system of the heart of the sheep and of the rabbit, and some preliminary observations are made on the human. The results are set out in this preliminary communication in the hope that the attention of clinicians and morbid anatomists may be directed to the lymphatic glands in cases of bacterial infections of the heart that may come under their notice. 1. THE SHEEP method. Sub-epicardial injections of Prussian blue (prepared according to the formula of Jamieson and Dobson) were made with a fine hypodermic needle into the dead heart. Flow along a main collecting lymph vessel was very obvious when a tributary was punctured and it was facilitated by centripetal massage. The arrangement of the lymphatic vessels was found to fall into two types, which may be called types I and II. The main collecting trunks are anterior and posterior, and it is in respect of the posterior collecting trunk that types I and II differ. Anterior collecting trunk. Fig. 1 shows the general disposition of lymphatic vessels revealed by a few injections near the apex of the heart. The main anterior collecting trunk is formed on the left side of the root of the aorta, just in front of the origin of the left coronary artery, and runs up in the interval between the pulmonary artery and aorta in a sub-epicardial mass of fat; its tributaries are very numerous and converge to the root of the left coronary artery by vessels from the right ventricle which run in the right part of the auriculo-ventricular groove, and others running upwards from the front of both ventricles to the same point. The areas of the sheep's heart supplied by the two coronary arteries are shown in fig. 6, and these may be compared with the areas of lymph drainage shown in figs. 1 and 2. It is seen that there is no correspondence between the drainage areas of the main lymphatic trunks and the distribution of the main branches of the coronary arteries, other than that certain lymph vessels lie near the arteries in the inter-ventricular and auriculoventricular sulci. The lymph drainage of the anterior trunk includes the whole of the front and most of the back of the right ventricle, as is shown in figs. 1 and 2. Posterior collecting trunk. Type I. Fig. 3 shows that the vessels from the back of the left ventricle and margo obtusus run to a vessel lying in the left part of the auriculo-ventricular groove. This vessel runs to the right and Anatomy BTT 9

2 126 L. R. Shore Fig. 1. Fig. 2. b.5. Cn. AC T / C.T L PV A~~~L - (> ~~~~~-TPCT Fig. 3.

3 The Lymphatic Drainage of the Heart 127 Fig. 4. Fig. 5. Fig. 6, 9-2

4 128 L. R. Shore forwards, closely applied to the anterior surface of the left auricle, where it lies in the posterior wall of the transverse sinus of the pericardium, after which it takes a vertical course on the antero-medial surface of the superior vena cava. The termination of this trunk is, as yet, undetermined. Posterior collecting trunk. Type II. Fig. 5 shows that this trunk drains a larger area than type I. In the specimen figured tributaries of this trunk are seen to drain an additional area on the back of the right ventricle, while in type I the area is approximately limited by the posterior inter-ventricular sulcus. The drainage area on the anterior surface is much the same as in type I. Tributaries converge to a trunk which runs from the left part of the auriculoventricular groove to the back of the left auricle, immediately to the right of the left inferior pulmonary vein. This trunk has not yet been traced beyond this point. 2. THE RABBIT Methods. The lymphatic drainage of the rabbit's heart has been studied in two ways: (1) Indian ink injection; (2) observations on rabbits the subjects of experimental endocarditis. Method 1. Indian ink was injected into the ventricular myocardium of the living rabbit and search made for lymphatic glands containing pigment. By steadying the heart for a few moments with the fingers it was not difficult to inject the left ventricle, but the small size of the animal and the thinness of the right ventricle made it difficult to do the same on the right side. As a result of dissection of the thoracic viscera of five rabbits the following results may be stated: (a) Lymphatic glands. A constant gland lies between the right superior vena cava and ascending aorta and in front of the right branch of the pulmonary artery. In figs. 7 and 8 I have sketched a case in which the gland was double; it seemed that there was some difference in the afferents to the two glands. In one rabbit an additional gland containing pigment was found on the back of the left bronchus, as depicted in fig. 9. I recently had the opportunity of examining the viscera of a rabbit in which a 1 in 50 suspension of carmine in saline had been injected into the pericardium 18 hours before death. The gland referred to above, near the right superior vena cava, contained pigment; no other gland containing pigment was found. The inference is that the gland between the right superior vena cava and the ascending aorta receives the lymph from the pericardium as well as from the substance of the heart. (b) Superficial lymph vessels and collecting trunks. As in the sheep it was possible to identify anterior and posterior collecting trunks. The anterior trunk resembles that found in both types in the sheep. The posterior collecting trunk in the rabbit differs from both types in the sheep. It passes from the back of the left ventricle into the left part of the auriculo-ventricular sulcus and then to the right in the anterior wall of the transverse sinus of the pericardium; thence it inclines upwards parallel to and slightly behind the anterior

5 LG. Fig. 7. Fig. 8. Fig. 9.

6 130 L. R. Shore collecting trunk, as shown in figs. 7 and 8. In four of the five rabbits the two glands shown in figs. 7 and 8 were merged into one; this specimen is figured as it shows the termination of the two separate collecting trunks. Method 2. Observations on rabbits the subjects of experimental endocarditis. Dr Mervyn Gordon has very kindly given me the opportunity of examining the thoracic viscera of four rabbits inoculated intravenously with micro-organisms for the production of endocarditis. I have recorded the position of enlarged glands and endeavoured to correlate them with the pathological lesions found. The observations are set out in the form of a table which includes the rabbits injected with Indian ink and those with experimental endocarditis. Table showing position of glands affected in the rabbit as a result of (1) Indian ink injection; (2) endocarditis of bacterial origin. Right superior Below Left superior caval group arch Paratracheal caval group Left ~ of A A para- Medial Lateral aorta Right Left Ant. Post. bronchial Experimental in jection of Indian ink into the sub stance of the ven triple Carmine injected into pericardium. Gland in arch of aorta not pigmented Multiple abscesses. Vegetations mitral and tricuspid valves Vegetations tricuspid valve and abscess L. vent. Early vegetations mitral valve Vegetations mitral and tricuspid valves Details relating to the rabbits in which endocarditis was induced: Rabbit 7. Figs. 10 and 11. Streptococcus pyogenes. Multiple abscesses of myocardium. Mitral and tricuspid vegetations. Rabbit 8. Fig. 12. Strept. pyogenes. Abscess left ventricle. Vegetations on tricuspid valve. Rabbit 9. Fig. 13. Strept. pyogenes. Early vegetations on mitral valve. Rabbit 10. Fig. 14. Strept. faecalis. Large vegetations on mitral and tricuspid valves. It will be noted from the table that the gland near the right superior vena cava is constantly affected. There is no indication of the lymphatic drainage of individual cardiac valves in respect of particular lymph glands.

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8 132 L. R. Shore L.S.V.C. -. -R. S.VC. AL. Fig THE HUMAN Special search has been made for lymphatic glands in the positions suggested by the study of the lymphatic system of the sheep and rabbit. A preliminary search in the post-mortem room in connection with a case diagnosed in life as infective endocarditis, showed the following glands enlarged (fig. 15): (1) near the superior vena cava; (2) on the back of the left auricle to the right of the left inferior pulmonary vein. The presence of a gland between the superior vena cava and ascending aorta and in front of the right branch of the pulmonary artery, recalls the gland found with such constancy in a similar position in the rabbit. The gland by the left inferior pulmonary vein recalls the disposition of the type IL posterior collecting trunk in the sheep. I propose to name these glands as follows: the gland that lies outside the pericardium, in the area defined by the superior vena cava, ascending aorta and right branch of the pulmonary-the caval gland of the heart; that which lies outside the pericardium, to the right of the left inferior pulmonary vein-the auricular gland of the heart. By the use of a precise nomenclature it is hoped that descriptions of post-mortem specimens may be facilitated. In the description of human material from the post-mortem room some emphasis is laid on the colour of the gland. A gland deeply pigmented with soot is suggestive of a connection with the bronchial system. Post-mortem observations as yet have been very few, beut the following are of interest: Case 1 (fig. 15) shows both caval and auricular glands enlarged. The auricular gland was about one and a half inches distant from the nearest black

9 -T-he Lymphatic Drainage of the Heart 133 bronchial gland, and it was not pigmented. There was endocarditis of both mitral and tricuspid valves. Case 2 (fig. 16) shows caval and auricular glands enlarged. The auricular glands were multiple, fleshy and contrasted with a deeply pigmented gland (presumably of the bronchial system) that lay just below the left pulmonary veins. Endocarditis of the mitral valve was present. Case 3. In a case of mitral disease of very long standing and extreme narrowing of the mitral orifice, a hard fibrous caval gland was found. L. C,. Fig. 15. R. PV Fig. 16. LG P This communication contains the data I have gathered up to the present on the lymphatic drainage of the heart, and I propose to conthiue investigations in the post-mortem room and laboratory. As yet, I have had no oppor-

10 134 L. R. Shore tunity of making a direct injection of Prussian blue into the caval or auricular glands of the foetus, nor have I attempted to describe the microscopic appearance of the lymphatic vessels. I wish to express my cordial thanks to Professors Elliot Smith and Lovatt Evans who have given nme facilities for work in University College, London, and much helpful advice; also to Dr Mervyn Gordon for the material he has placed at my disposal. To Dr Francis Davies I owe my best thanks for assistance at all stages of this investigation, for presenting this paper in my absence and for many other acts of friendship. LITERATURE CONSULTED CUNNINGHAM (1922). Human Anatomy, 5th ed. GRAY (1926). Human Anatomy, 23rd ed. JAMIESON and DOBSON (1910). Jour/i. A/at. a/d, PI/ys. vol. XLV. MORRIS (1915). Human Anatomty, 5th ed. PIERSOL (1912). Hu/nan Anatomy, 8th ed. TANDLER (1913). Anat. des Herzens.