A COMPARATIVE STUDY OF THE LYMPHATICO

VENOUS COMMUNICATIONS IN ADULT
MAMMALS.

I. PRIMATES, CARNIVORA, RODENTIA, UNGULATA AND MARSUPIALIA.

BY

CHARLES F. W. McCLURE AND CHARLES F. SILVESTER.

A COMPARATIVE STUDY OF THE LYMPHATICO

VENOUS COMMUNICATIONS IN ADULT

MAMMALS.

I. PRIMATES, CARNIVORA, RODENTIA, UNGULATA AND MARSUPIALIA.

BY

CHARLES F. W. McCLURE AND CHARLES F. SILVESTER. From the Laboratory of Comparative Anatomy, Princeton University.

WITH THREE TEXT-FIGURES AND TEN PLATES.

Huntington and McClure1 have shown in the adult cat (Felis domestica) that the communication between the lymphatic system and the systemic veins may normally occur on each side of the body, within either one of two or within two typical districts. These two districts include, approximately, the angle of confluence formed by the union of the external and internal jugular veins (common jugular angle) and the angle of confluence formed by the union of the external jugular2 and subclavian veins (jugulo-subclavian angle). An examination of a large number of adult cats proved conclusively that neither one of these two districts predominates as the place of communication between the lymphatics and the veins, but that either

'Huntington and McClure, The Anatomy and Development of the Jugular Lymph Sacs in the Domestic Cat (Felis domestica). A paper read before The Association of American Anatomists in Chicago, in 1907, published in THE ANATOMICAL RECORD, Volume II, 1908, and soon to be published in a more complete form in The American Journal of Anatomy.

"This vein, strictly speaking, is a common jugular vein in the cat, but on account of its large size, as compared with the internal jugular, is usually spoken of as the external jugular vein of which the internal jugular is a tributary.

one of the two or both may serve equally in this capacity and for this reason both districts must be regarded as constituting normal points of communication between the lymphatics and the veins.

In following the development of the jugular lymph sacs in the embryonic cat Huntington and McClure were able to establish the basis upon which the duplex character of the lymphatico-venous communication in the adult rests. They found that the right as

TEXT-FIG. I.—A reconstruction of the left jugular lymph sac of a 11 nim. cat embryo (Felis domestica) showing the relations of the thyrocervical artery to the jugular and subclavian approaches through which the two typical adult communications are established between the lymphatics and the veins. Ventral view. Drawn from a reconstruction made by Huntington and McClure after the method of Born.

well as the left jugular lymph sac in the embryonic cat invariably presents two caudally directed processes or prolongations which they termed, respectively, the Jugular and Subclavian approaches (Textfig. I). These two processes, on each side of the body, are directed

toward and approach the district of the common jugular angle and the district of the jugulo-subclavian angle, respectively, and they observed that it is through either one of the two or through both of these processes that the adult communication is established, a circumstance which accounts not only for the presence of a double communication in the adult cat but also establishes it as a character of morphological significance.

In view of the uniform conditions which prevail in the adult domestic cat concerning the presence of two typical districts of lymphatico-venous communication on each side of the body, the present writers have undertaken to determine to what extent this same uniformity may prevail in adult mammals in general.

We have thus far examined twenty-five (25) species distributed among fifty (50) adult mammals (24 primates, 4 carnivora, 12 rodents, 5 ungulates and 5 marsupials). These mammals were chosen at random from the Princeton Collection so that the conditions observed in them represent fairly well the average conditions which one might expect to find in any other similar group chosen in the same manner. The lymphatic system of each mammal was injected with gelatine and then carefully dissected out in the appropriate regions on each side of the body. A drawing to scale was made of each dissection to facilitate comparison. All of the figures in this paper therefore represent accurately the arrangement of the lymphatics as met with in the regions of communication and it is worthy of notice that the lymphatics present a marked variability, more so than the veins, not only in the different species examined but among different members of the same species. These variations will not be dealt with to any extent in the present paper except in so far as it becomes necessary to speak of them in connection with the communications which exist between the lymphatics and the veins.

We may state at the beginning that we are warranted in drawing the conclusion from the adult mammals thus far examined that the lymphatic system normally communicates with the veins in these forms as in the adult cat, either at one of two or at two typical districts (common jugular and jugulo-subclavian districts) and that a communication at the two typical districts is the commonest of the