[in-truh-thee-kuh l]
  1. Anatomy. situated within the thecal sac: covering the spinal cord.
  2. Medicine/Medical. administered into the thecal sac: intrathecal injections.
  1. Pharmacology. anesthesia administered into the thecal sac: She was given an intrathecal during labor.

Origin of intrathecal

First recorded in 1885–90; intra- + theca + -al1
Related formsin·tra·the·cal·ly, adverb Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018