Preliminary note upon the cell lamination of the cerebral cortex of echidna, with an enumeration of the fibres in the cranial nerves / by Edgar Schuster.

  • Schuster, Edgar.
Date:
[1909]
Catalogue details

Licence: In copyright

Credit: Preliminary note upon the cell lamination of the cerebral cortex of echidna, with an enumeration of the fibres in the cranial nerves / by Edgar Schuster. Source: Wellcome Collection.

Provider: This material has been provided by King’s College London. The original may be consulted at King’s College London.

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    or bulb. The greatest depth of the fissure is 7 or 8 mm., but the incision referred to is 9 mm. deep. Fissura rhinica posterior (frhp) runs at first basal wards, then turns horizontally backwards, and describes finally a flat curve with its concavity directed downwards. Its posterior segment, sometimes separated from the main division, cuts the posterior mesial border of the hemisphere. The depth in the anterior division is about 7 mm., but gets considerably less posteriorly. Fissura postsylvia anterior (fpsa) [Elliot Smith, «] approaches the sylvian fissure at its lower end in a characteristic manner; it runs upwards and backwards and cuts the mesial border of the hemisphere 25 mm. from the frontal pole. It may be straight or wavy, but there is always an angular bend in the middle third from which a posteriorly directed side branch is given off. The depth is between 2\ and mm. Fissura postsylvia posterior (fpsp) lies 6 mm. behind fpsa; it cuts the border of the hemisphere behind the occipital pole, i.e. behind the point where the border runs laterally outwards. The fissure runs continuously downwards and forwards as far as the angle of fpsa, but in front of this its direction is continued by an anterior segment. The main fissure is called . postsylvia posterior occipitalis (fpspo) [Elliot Smith, f], and is 2\ mm. deep. The anterior segment is called f. postsylvia posterior temporalis (fpspt) [Elliot Smith, 77], and is If mm. deep. Occasionally another fissure, f. postsylvia postrema, is present behind and parallel to fpsp. Fissura antesylvia posterior (fasp) [Elliot Smith, /8] is the most constant of the fissures in the anterior part of the brain; it lies parallel to fpsa, 2 to 6 mm. in front of it. When well developed its lower end lies over the sylvian fissure. In this region it often turns sagitally forwards and may be forked. Its depth may reach 3 mm. Between it and fpsa there may be another fissure. Fissura antesylvia anterior (fasa) [Elliot Smith, 7 and B) lies parallel to and in front of fasp. It is sometimes as well developed as the latter, and cuts deeply into the mesial border of the hemisphere. More often it is weakly developed, failing to reach the border and sometimes falling into two pieces. Its lower end may be forked, depth to 3 mm. Fissura} frontomarginales superior and inferior (ffs and ffi) [Elliot Smith, e] lie in front of fasa; they are very variable. On the median surface of the brain may be found the Fissura hippocampi (FH) which follows the characteristic course of the hippocampus, starting in the upper anterior part of the brain, running backwards and then curving downwards and finally forwards, to end somewhere below its starting point.