Injection into the extra-arachnoid subdural space. Experience in the treatment of intractable cervical pain and in the conduct of extradural (epidural) analgesia.

The anatomy and radiological appearances of the subdural space in the cervical region are described. Recognition of this space facilitates neurolytic injections for severe cancer pain in the distribution of the cervical nerve roots. The subdural space may have significance also in explaining the extensive sensory block which follows a delayed or 'massive' lumbar extradural injection.