An introduction to pathology and morbid anatomy / by T. Henry Green ; revised and enlarged by H. Montague Murray.

  • Green, T. Henry (Thomas Henry), 1841-1923
Date:
1900
Catalogue details

Licence: In copyright

Credit: An introduction to pathology and morbid anatomy / by T. Henry Green ; revised and enlarged by H. Montague Murray. 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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    ctinal and separated from the orifrinally adjacent epiblast by a thin layer of mesoblast. The grossest forms of malformation depend upon tiie failure of the neural groove to form the neural canal. Thus, both cranium and brain may be absent (aiieiwepha/iix), and the spinal canal and spinal cord may remain an ojien groove (open xpiiiu bijida). These conditions, as well as many other malformations of the brain, are incompatible with life and are, therefore, of little practical interest. A lesser degree of spina bifida often occurs, in which a hernial protrusion either from the central canal of the spinal cord or merely from the spinal canal, combined with defective formation of the arches of the vertebrsE, forms a central tumour in the back—usually in the lumbar region. When the tumour consists of a protrusion from the central cnnal of iha spinal cord, its wall is lined internally by nerve-roots and rudiments of the spinal coi-d {syringonujcloccle). When the protrusion only arises fi'om the spinal canal, and not from the centre of the spinal cord, the latter generally runs across the cavity and is attached to the middle of the projecting wall of the pi'otrusion, giving rise to a central depression in the tumour when viewed from behind: thence it turns back and, as the Jihim ierniinale, reaches the canal again. In such cases {imjelomeningocele^, as well as in those which only contain fluid, the wall of the tumour is formed of the ordinarj^ integuments lined by the rudimentary spinal meninges. Similar pouches may be formed in connection with defects in the cranium. The)^ generallj' arise from the occipital region. They may contain brain-substance {enccpkalocele), or brain-substance and fluid {encephatomeningocele), or fluid only (Menin- gocele). Malformations of both brain and spinal cord may also arise after the cranium and vertebral column are formed. These comprise (l) a uniform smallness of the brain (viicrencepknlia') or of the spinal cord (micro7ni/elia) in which the former ma}'^ be from two-thirds to one-sixth its natural size; (2) irregular defects in the corte.K of the brain in which some of the convolutions are absent, and others small and thin ; and (3) more or less extensive depressions or clefts in the cortex due to defective development and constituting the condition known as porencephalia. The cerebrum and cerebellum are more liable to mal- formations than the centi'al parts of the brain. The spaces resulting from the defects in the cortical or central parts occurring after the iormation of the cranium, are filled up by cerebro-spinal fluid — in the ventricles or in the subarachnoid spaces, as the case may be. Wiien the defects are marked and the quantity of fluid is large, the condition is known as congenital hi/droccp/ialiis~internal, if the fluid is in the ventricles, and external, if it is on the surface of the brain. The majority of instances of malformation are probably due to
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