Universlty of Manitoba, ln Partîal Fulfiìlment - MSpace at the ...

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1.5.5 Anter ìor Spina _Bif idg
Flnally, defects of the vertebral bodies rather than the neural
arches may occur. These anterior spina blfidas appear to be of two
distlnct types ;
a) lsolated anter¡or meningoceles in the thgracic cr lumbar region
are very often associated w¡th cutaneous neurofibromatosis, and may be
a complicatîon of von Reckr inghausenrs disease (ta viene and campber r,
1958; Sammons and Thomas, '|959).
b) ln another group varying degrees of connection may occur between
the gastro¡ntestinal tract or an enteric cyst,ând the spina.l cord or
even overlying skin. These connect.ions pass through the anterior spina
blfida, which may be accompanied by dupl icatíon óf the notochord or even
of the spinal cord (Bremer, 1952; Fal lon et el., 1954).
ln some cases the neuro-ente¡¡c connectícn and.anterior spina
bífida are combîned with an open posterior spina bíf¡da (Saunders, 1943).
1.6 CRANIUM BIFIDUM
The term cranium bifidum may be used to embrace a comparable group of
open defects of the skul l.
1.6,I Anencepha,b¡, Exenqeph¡¡ Ly
The commonest of these malformations involving both skult Ur"in
ls "n¿
known as anencephaly, though the term is misleading as the brain is
rarely completely absent. riost fut term fetuses show ross of a variabre
amount of braín tissue and replacement by abnormal neuro-vascular materiar,
sometlmes called pseudencephaly (
Geoffroy_St. Hílaire, t836).(Fis. l).