. Tumours, innocent and malignant; their clinical characters and appropriate treatment. other regions of the skull they are excessively rare.It is usually stated that they may appear at the anteriorfontanelle, but critical examination of the descriptions of sus-pected cases makes it probable that many of the supposedmeningoceles were dermoids (p. 460). CRANIAL MENINGOCELE 635 Occipital meningoceles appear, during life, to protrudethrough the foramen magnum ; when the parts are dissectedthe pedicle will be found to make its way through a gap inthe supra-occipital between the posterior margin of
Image details
Contributor:
The Reading Room / Alamy Stock PhotoImage ID:
2AG2XFRFile size:
7.1 MB (475.9 KB Compressed download)Releases:
Model - no | Property - noDo I need a release?Dimensions:
2218 x 1126 px | 37.6 x 19.1 cm | 14.8 x 7.5 inches | 150dpiMore information:
This image is a public domain image, which means either that copyright has expired in the image or the copyright holder has waived their copyright. Alamy charges you a fee for access to the high resolution copy of the image.
This image could have imperfections as it’s either historical or reportage.
. Tumours, innocent and malignant; their clinical characters and appropriate treatment. other regions of the skull they are excessively rare.It is usually stated that they may appear at the anteriorfontanelle, but critical examination of the descriptions of sus-pected cases makes it probable that many of the supposedmeningoceles were dermoids (p. 460). CRANIAL MENINGOCELE 635 Occipital meningoceles appear, during life, to protrudethrough the foramen magnum ; when the parts are dissectedthe pedicle will be found to make its way through a gap inthe supra-occipital between the posterior margin of the fora-men magnum and the occipital protuberance. This spaceduring early embryonic life is occupied by a fontanelle. The relations of the flocculus in cases of occipital meningo-cele are of importance. In the descriptions of reported casesof this malformation the cerebellum, if referred to, is describedas rudimentary or absent. As a matter of fact, in these casesthe cerebellum is absent, and that which is supposed torepresent this part of the brain is an enlarged flocculus (Fig.. Flocculus.Fig. 335.—Occipital meningo-encephalocele. The cyst probably represents an ex-panded fourth ventricle : there was no cerebellum, but a large and conspicuousflocculus. 335). Cleland has pointed out that the flocculus is developedfrom a lateral outgrowth of the floor of the third encephalicvesicle, whilst the cerebellum is developed from the foremostpart of the roof of that vesicle. An appreciation of this factthrows valuable light on the nature of occipital meningocele, for the absence of the cerebellum indicates that the hernialprotrusion is the third encephalic vesicle; instead of itswalls thickening to form a cerebellum, they become pas-sively dilated into a cyst. Indeed, this form of meningocelebears much the same relation to the fourth ventricle andthe cerebellum that hydrocephalus bears to the lateralventricles and the cerebrum. An occipital meningocelemight not inaptly be described