An atlas of the medulla and midbrain / Edited by H.McE.K.

  • Florence R. Sabin
Date:
1901
Catalogue details

Licence: In copyright

Credit: An atlas of the medulla and midbrain / Edited by H.McE.K. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    .MICin;i,LA 01iU)MUATA, PONS AXD .MIDIIKAIX cerebralward the fascicniliis ciineatiis shows the same change. This capsule can be best understood after the nucleus has been described. The nucleus of the dorsal funiculus of the cord is seen best after removing the fibre capsule (Plates III and VI). It is an irregular mass of cells, which is divisible into three parts; moreover, this divi- sion, made from form alone is strengthened by the mode of dis- tribution of the fibres. In general the distal ]wrtion of the nucleus has a long diameter in a dorsoventral plane (Plate \) at right angles with the long axis of the proximal portion (Plate III). The three di^asions, as seen from a lateral view are (1) a distal, (2) a middle and (3) a proximal part. The middle portion does not extend to the mesial surface of the nuclear mass and so may well be called the lateral portion. (i>fucleus funiculi cuneati lateralis, Plate III.) The distal part or nucleus funiculi gracilis consists of a column of cells placed in a doi-soventral direction. Its distal margin is straight but the dorsal margin is curved and raised above the rest of the nuclear mass (Plate III). It is separated from the middle nucleus by a deep groove but its surface is smooth, thereby contrast- ing with the proximal portion. The rest of the mass has been called the nucleus funiculi cuneati, but Blumenau has shown that it consists of two distinct parts. The middle part, or nucleus of Blumenau is a mass of cells projecting from the lateral surface. (Plate III. l^ucleus funiculi cuneati lateralis). It is separated from the distal nucleus by a deep groove but fades gradually into the proximal nucleus. Its distal border is about opposite the middle of the nucleus funiculi gracilis, while its proximal limit is opposite the lower part of the nucleus olivaris inferior, and the distal end of the radix descendens nervi vestibuli. In the model, the nucleus cannot be ti'aced as far cerebralward as Blumenau was able to trace it from histological details. Blum- enau ' places the proximal limit opposite the lowest plane of en- trance of the fibres of the jST. acusticus. The sections of both my series show small, scattered masses of cells in the corpus restiforme, and these can be traced even into the cerebellum itself. They are considered by Blumenau to be part of the nucleus which bears his name. As has been said, the nucleus of Blumenau docs not reach the mesial surface of the nuclear mass. The thin mesial zone con- ' Tihnneniui, L.. TTeber den iinsseren Kern des Keilstraiifjes im verliiii- gerten Mark. Neurol. Centralbl.. Leipz.. Ed. X (1S91). S. 229.