An intrathecal injection is a medical procedure where medication is delivered directly into the spinal canal, specifically into the cerebrospinal fluid. This method allows for faster and more effective treatment of conditions affecting the central nervous system, as the medication bypasses the blood-brain barrier. This type of injection is often used for pain management, chemotherapy, or to administer anesthetics. It is typically performed by a trained healthcare professional using a thin needle, ensuring precise placement to minimize risks and maximize therapeutic effects.