On traces in the heart of its transitions in form during foetal life. Part I / by P.D. Handyside.

  • Handyside, P. D. (Peter David), 1808-1881.
Date:
1869
Catalogue details

Licence: Public Domain Mark

Credit: On traces in the heart of its transitions in form during foetal life. Part I / by P.D. Handyside. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the posterior wall, and at the rim of entrance, of the superior cava a well defined and deep lacuna, within which open five large The- besian foramina. The caval half of the patulous border of this lacuna is protected by an oblique semilunar valve, one quarter of an-inch in breadth and of a like depth. This valve is composed of a duplicature of endocardium, and is evidently designed to secure the entrance of blood into the auricle.* The author next compared shortly these three abnormal cases, demonstrating how they formed at once a graduated scale or an- atomical series mutually illustrative, each specimen introducing to the mind its own peculiar features of morphological interest. He considered, however, these cases as chiefly interesting—when compared with the results of certain changes undergone by the human embryo between the third and the seventeenth weeks after conception—in relation with the structural aSinities they present to permanently impressed forms in some cold and warm-blooded animals; after a like manner to what is seen in the venous system of fishes as a permanent form of structure, and yet presents itself, but temporarily in the history of the development, during their embryo state, of higher vertebrate animals. He referred to homo- logues in the Myxinoidei family of fishes ; to the Ophidian order of reptiles ; among birds, to the Aqidla chrysaetos and the Casuarius emeu; and amongmammaZs, to theDelphinus'phoc(Bna,i'h.QMacropus, * The additional sketches, figs. 3 and 4, represent peculiarities in two adult hearts, and fig. 5, in a foetal heart, dissected in Dr Handyside's rooms. In fig. 3 a valve (J inch broad by J inch deep), formed of endocardium with an intervening lamina of striped muscle, lay within and parallel to the pos- terior segment of the rim of the superior cava. In fig. 4 is an unusually large persistent Eustachian valve, continuous at its left insertion with a still more remarkable Thebesian valve. The former, which is very large, has an insulated fibrous ofi'set from its left extremity, which runs half-way across the sinus venosus towards the tubercle of Lower, and then dichotomously divides and subdivides thrice before it is implanted into the arched Uno between the right comu of the Eustachian valve and the right segment of the rim of the superior cava. Fig. 5 represents, in a male foetus of 6 J months, presented to Dr Handyside's museum during last summer, the occurrence of a complete semilunar valve situated at the termination of the upper vena cava, its convex border being attached to the anterior and right wall of the vein, its concave free border projecting into the auricle. The right crus of this valve is inserted into the auricular wall on a plane J of an inch behind, and de- cussating, the right ascending corrni of the prolonged Eustachian valve.