Anesthesia of the lower half of the body; caused by injury to the spinal cord or by injecting an anesthetic beneath the arachnoid membrane that surrounds the spinal cord WordNet 3.0 & Open English WordNet

Spinal anaesthesia, also called spinal block, subarachnoid block, intradural block and intrathecal block, is a form of neuraxial regional anaesthesia involving the injection of a local anaesthetic or opioid into the subarachnoid space, generally through a fine needle, usually 9 cm long. Wikipedia

Form of neuraxial regional anaesthesia Wikidata

A spinal anesthesia. Wiktionary