ANATOMY OF DIPLEGIA - AN HYPOTHESIS

Periventricular leukomalacia (PVL) occurring in relation to the body o f the lateral ventricle could account for damage to the corticospinal tracts. However, PVL in this location is relatively rare, and the view that it causes the diplegia of preterm birth is challenged on the ana tomical grounds that the corticospinal tracts to the legs are some dis tance away from the main sites of PVL, which are at the collateral tri gone and near to the interventricular foramen. If PVL lesions do cause permanent nerve damage, it is surprising that cortical blindness in d iplegia is so uncommon. A dying-back neuropathy caused by selective da mage to corticospinal neurons could be considered as an alternative hy pothesis to account for the paralysis of diplegia.