Observations on the relation of the principal fissures and convolution[s] of the cerebrum to the outer surface of the scalp / by Robert W. Reid.

  • Reid, Robert William, 1851-1939.
Date:
1884
Catalogue details

Licence: Public Domain Mark

Credit: Observations on the relation of the principal fissures and convolution[s] of the cerebrum to the outer surface of the scalp / by Robert W. Reid. 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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    volutions, first indicate on the surface of the scalp the longi- tudinal fissure and the horizontal limb of the fissure of Sylvius ; next, from the base line draw two perpendicular lines to meet the line for the longitudinal fissure, one (d e. Fig. i) from the depression in front of the external and auditory meatus, and another (f g. Fig. i) from the posterior border of the mastoid process at its root. We shall thus have described on the surface of the head a four-sided figure, bounded above and below by the lines for the longitudinal fissure and hori- zontal limb of the fissure of Sylvius respectively, and in front and behind by the two perpendicular lines. If we now draw a diagonal line (f h. Fig. i) from the posterior superior angle to the anterior inferior angle of the space, this diagonal line will lie over the fissure of Rolando. In the majority of cases the fissure of Rolando does not actually run into the fissure of Sylvius, a convolution bridging across at that point; hence the lowest half-inch or so of the line would cross this con- volution. In those cases where the two fissures join, the fissure of Rolando would be indicated by the whole length of the line. External paricto-occipital fissure.—This fissure is more variable in its position than any of the other principal fissures of the cerebrum, and consequently any indication of it on the surface of the scalp must be approximately accurate. If we continue the line for the horizontal limb of the fissure of Sylvius onwards to the line indicating the longitudinal fissure, we shall find that on trephining over the inner inch of this line we shall expose the external parieto-occipital fissure, or some part of it. In most cases we have seen the whole of the fissure in the opening so made, in others it showed itself in the posterior half of the opening, and in still fewer cases it was seen in the anterior half. Having now indicated the position of the principal fissures, it will be comparatively easy to map out the areas of the frontal, parietal, temporo-sphenoidal, and occipital lobes, with their chief sulci and convolutions as far as they are in relation with the outer surface of the scalp.