An atlas of the medulla and midbrain : a laboratory manual / by Florence R. Sabin ; edited by Henry McE. Knower.

  • Florence R. Sabin
Date:
1901
Catalogue details

Licence: In copyright

Credit: An atlas of the medulla and midbrain : a laboratory manual / by Florence R. Sabin ; edited by Henry McE. Knower. Source: Wellcome Collection.

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    General relations that the ventral regions of the model are occupied largely by nu- Shown in model clear masses: the olive, the pontal nuclei, the substantia nigra and the red nucleus. The absence of medullated fibres in this region is due to two facts, (1) that the pyramidal tracts and the brachium pontis which belong here become medullated at a later period, and (2) that, at the cervical curve in the medulla, most of the fibres of the spinal cord curve dorsalward, and thus leave the olivary region comparatively free. At this stage of the development the ventral level of the medulla oblongata, pons and midbrain is a nuclear region. Dorsal to this level is the area corresponding more or less to the continuation of the spinal cord. In the views of the model, one is struck by the number of fibre bundles this dorsal level contains, long and short paths, that is, tracts to the cerebrum and cerebellum as well as fibres to and from many way-stations. ‘These fibres represent in part the funiculi of the cord. The region is not wanting in nuclei, for the dorsal and ventral columns of the cord are represented by the nuclei of the cerebral nerves. The ground bundles of the cord correspond to the extensive formatio reticularis alba and grisea, while the central gray matter of the cord becomes much enlarged to form the substantia grisea centralis of the me- dulla, pons and midbrain.