On the arrangement of the fibres of the heart / by Henry Searle.

  • Searle, Henry.
Date:
1838
Catalogue details

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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    he base, pass more longitudinally. It is evi- lent that these few fibres would be inadequate 0 form a complete layer, unless in their pro- ongation they pursued an uniformly spiral :ourse. They are more than enough to cover he apicial part as they twist over each other; >ut in consequence of the conical form of the leart they soon become singly arranged, and s they diverge, separate and leave interspaces, ome of which are occupied by fibres which pparently arise abruptly at the surface. The ibres which pass longitudinally to the base of he left ventricle are inserted into the tendinous nargin of the annulus arteriosus, and into the >osterior part of the root of the aorta, forming he right wing, crc. The spiral fibres have teen stated to arrive at the anterior coronary rack along its whole length. The majority of hem terminate at the coronary vessels; others .re merely intersected by them, while others >ass under these vessels aud become super- icial again : those which maintain their course iver the right ventricle vary in different hearts rom a small to a considerable number. Along he whole length of this track accessory fibres rom the interior of the right ventricle are merging to associate with these in their way >ver this ventricle. They take a longitudinal ourse to the base, and therefore start at an ingle with the spiral fibres which are on the eft side of the coronary track. In Jig. 4 hese accessory fibres from the aorta, a a, and iom two of the carneae columnae, are seen lassing together obliquely down the right sur- ace of the septum, marked acc, to enter nto the formation of the extended band, rhese accessory fibres perforate it along the interior boundary, ab, and become super- icial. This layer is, accordingly, in fig. 2, narked Cacc ; its fibres pass at nearly right ingles with the subjacent fibres, and when aised form the left wing; its insertions are he anterior part of the root of the aorta, the endinous margin of the annulus venosus, and igain the right part of the root of the aorta, sometimes festoons are formed at the base by :ommunications of fibres between the pulmo- lary artery and the aorta, at its right and pos- erior aspects. It occasionally happens that the accessory ibres which arise from the interior of the right ventricle are not very numerous; in such cases 1 greater number of fibres arise abruptly from ts surface. The superficial layer has three sets of ori- gins: one, primitive, from the interior of the eft ventricle; the others, accessory, from the nterior of the right ventricle, and from the )uter surface of both. It cannot with pro- iriety be considered as one common invest- nent, since each ventricle for the most part jives birth to its own superficial fibres. It is lecessary to raise it as a distinct layer for two the left ventricle, and of forming the apex ill and probably no other method than that of th< 1. twisting of the fibres could have been so secure || especially as the parietes at the apex of tin 11 ventiicle do not generally, even in a bullock’; B’j heart, exceed a tenth of an inch in thickness. The second stage.—The external layer havingJI been traced from its origins to its insertions we may now trace the deep-seated layers; ancidM \ as these have, for the most part, the same*'! origins, courses, and insertions as the super--U1 ficial layer, we may commence the description || at the same points. It has been already stated that the fibres ofM ‘ the rope and of the two carneae columnae ex-.41 pand in a fan-like manner, that their inmost-II ■ fibres pass through the apex and become ex-41 ternal, but that the chief of them wind round:||1 the axis of the left ventricle above the apex. .|| as exemplified in fg. 2, crc. The respec-4| tive sets of fibres pertaining to these three- B bodies continue separate during their radiation ill only, after which they become plaited togetherll by folding one over the others. Their mode' II of association is shown in the extended portionnll of the split layer, crc in fg. 3, also innil its counterpart, crc, winding round the api--|| cial part of the ventricle. Again, in fg. f,.l it may be seen that the fibres at the bases of'ijl these columns turn under and pass up in con—1| junction with those of the rope forming theeil middle mass, crc, at the upper of which.|| they fold over making flat twists upon them— U selves, which have, however, become exag— U gerated in appearance by the unwinding of thei II heart, as in rolling it up again some of thee II angles are converted into spires, preserving aill considerable degree of parallelism. Having shown the origins, and the method!I adopted in the association, of the fibres form— II ing the middle mass in fg. 1, we proceed byvfl tracing the divisions and prolongations of itssn fibres, and the plan of building up the two) I chambers of the heart. First, the forma-U tion of the left ventricle. If the right carneaiH columna, cc, be replaced in contact with itssB fellow, and if the rope, rr, be brought I round the upper part of this cavity so as to I embrace them, and if portion 4 be split from 11 the middle mass, crc, and be wound, in I association with the apicial fibres, crc, round II the lower part of this cavity, that division of I the heart, comprising the left ventricle and the I middle mass, will bear a near resemblance to I that represented in fig. 3; in which figure I the rope, rr, in embracing the heads of the carneae columnae, cc, brings into view its fan- like fibres, r, sweeping round the upper part of the axis of this ventricle; in which the fibres of portion 4, in winding round the lower half of the axis, embrace the bodies of the carneae columnae, cc, and associate with the in whirl, the pv.