ch. 1. Introduction : why investigate atypical epidural blocks? -- ch. 2. The technique of epidurography -- ch. 3. The typical epidurogram -- ch. 4. Complicated epidural blocks -- ch. 5. The subdural and intradural spaces -- ch. 6. Failed epidural blocks and misplaced catheters -- ch. 7. Failed epidural blocks caused by an obstructive septum -- ch. 8. Spinal deformity and epidural block -- ch. 9. An assessment of epidural catheters : the role of epidurograms -- ch. 10. Conclusions.