On the arrangement of the fibres of the heart / by Henry Searle.
- Searle, Henry.
- Date:
- 1838
Licence: Public Domain Mark
Credit: On the arrangement of the fibres of the heart / by Henry Searle. 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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![them within their proper spheres of action, and since the fibres of the heart are devoid of this agent, the question arises as to what other retaining power these possess. On this head no difficulty presents itself; for the fibres, in winding round and round the cavity of the left ventricle, become arranged in concentric layers ; and in taking a larger sweep, in surrounding the right ventricle, the same arrangement is preserved, so that during the systole of the heart the whole mass of the fibres firmly com- press each other, which necessarily retains them all within their proper spheres of action, ex- cepting the superficial fibres, of which those towards the base, and especially those upon the right ventricle, where there is great latitude of motion, do not preserve a parallelism with their subjacent fibres, but lie nearly at right angles with them. It is on this account, most proba- bly, that the superficial fibres have attracted notice, and have been viewed as a distinct layer. The disposition of the fibres varies in diffe- rent parts of the heart, forming parallel lines, angles, decussations, flat and spiral twists. The fibres are arranged in fasciculi, bands, layers, and a rope, which are so entwined together as to form the two chambers called the right and left ventricles. These are lined with their in- ternal proper membrane. The fasciculi are connected with the aorta, pulmonary artery, and came® column®, and contribute to the formation of the bands. The bunds.—By tracing the fibres in bands, we are enabled to develop the formation of the ventricles in a progressive and systematic man- ner. The bands spring from a mass of fibres which forms the apicial part of the left ventricle, and which, in winding round just above the apex of the heart, separates into two bands to form the right ventricle. It will render the demonstration more intel- ligible if a preliminary and cursory view be taken of the general course of these bands (jig- 6, p. 10,) by referring to the diagram. The bands, as there given, form a mere skeleton of the heart, merely indicating the se- veral courses they take. The average width of the bands is not less than a third of the extent between the apex and base of the left ventricle. In the diagram, crc indicates the winding of a considerable mass of fibres just above the apex; at the septum, s, it splits into two bands. The shorter, Cacc, encircles spirally both ventricles, one half round the right, the other round the left ventricle. The longer band de- scribes two circles: it first passes through the septum, round the left ventricle marked Cpca ; it secondly passes round the base, and includes both ventricles in its circuit, marked progressively Cpcaa,Cpcaaa, CpcaaaaC, and RR. lions of the fibres and of their respective origins] the latter are characterised by double, and the former by single initials. Accordingly, the aorta, the pulmonary artery, the rope, and the carneae and cc mated aa, pp, rrJ column® are desij; , while their fibres are marked a, p. and c. This plan is modified in one instance only, viz., the fibres of the main bulk of the heart, being derived from the rope and the twe] carne® column® of the left ventricle, are desig-. nated in the first instance by their proper inij tials crc ; but as numerous increments 01 fibres are being made, in succession, to thesi three original sets, it is convenient to make ai abbreviation in the lettering; thus, crc is in dicated by C large, when combined witl other initials; accordingly, cp.ca is con traded to Ca, and crcpca to Cpca, and s< with the rest. The layers.—Although the heart admits o being split into a number of layers, yet then being no material division formed by fasci® o condensed cellular membrane, such separation are strictly arbitrary. It is, however, foun< convenient to separate the fibres into certaii layers, in order to give a methodical de monstration of the formation of this orgar The same remarks obtain regarding the bands. It is generally supposed that the superfici; fibres properly constitute a distinct layer, form ing a common sac, which encloses the tw ventricles. This is not strictly the case, for has the same origins and terminations as have tl fibres immediately subjacent to it. Nevertlu less, the superficial fibres are, in the followin description, considered as a separate layer, 1 show the peculiar construction of the apex. The rope.—It has already been stated tli the longer of the two bands terminates at tl base in the rope. The fibres of this band, i forming the brim of the left ventricle, make sharp twist like those of a rope, by whi< means they become the inner fibres of tli chamber, and expand into a layer which ente largely into the formation of the mass whit divides into the two bands. So the princip band, although it receives several increments fibres, has no complete beginning nor endin a considerable portion of it originating and te minating in itself, which circumstance rende it necessary to fix upon the most convenie part of its course for the commencement of tl demonstration. Although the system here adopted of unr veiling the fibres of the heart be strictly arl trary, as every other must be, yet it will, me probably, be found the only method by whii all the various courses, and several connexioi made by the fibres in forming the heart, cou be displayed. The demonstration.—It is requisite to pn sue two methods of demonstration ;—one, unfaUintr](https://iiif.wellcomecollection.org/image/b22386476_0007.jp2/full/800%2C/0/default.jpg)
