[Morphological findings in MRI to be considered in perfoming spinal and epidural anesthesia].

The spinal cord and cauda equina move in the subarachnoid space by changing positions. The subarachnoid space is compressed from the dorsal side by epidural injection. At the end of gestation, the subarachnoid space is compressed from the ventral side by the engorged venous plexus. Idiopathic epidural lipomatosis is observed almost exclusively in the obese population. In the case of lipomatosis, the subarachnoid space is compressed by increased extradural fat around the thecal sac. We have had some severe cases of spinal canal stenosis in whom it is difficult to perform the spinal puncture. The authors showed some MR images and discussed morphological issues for spinal or epidural anesthesia.