Amyelia

AMYELIA, amyelia (from the Greek a- negative particle, and myelos- spinal cord), absence of the spinal cord, a malformation associated with complete splitting of the vertebral canal (rhachischisis totalis). Due to the absence of the posterior parts of the vertebrae, the vertebral canal appears as an open groove posteriorly, at the bottom of which lies the ventral layer of the dura mater. The spinal cord may be completely absent or present only in certain places as a pinkish mass consisting of improperly formed nervous tissue with numerous blood vessels. Typically, the absence of the spinal cord is combined with acra-pia and anencephaly (see).