We thank Dr Silver for his interest and for drawing our attention to previous papers.

In clinical practice we are familiar with the phenomenon of cord oedema and paralysis in street drug users.

In the case described we found such a close and instantaneous temporal and anatomical relationship of the injection to the damaged cord that we believe there must have been immediate arterial damage, at the instant of injection.

We believe that street Heroin injected peripherally, as described by Dr Silver, is likely to cause myelopathy by a different mechanism.