Where is the local anaesthetic introduced in spinal anaesthesia?

The injection of a relatively small dose of local anesthetic into the subarachnoid space (between pia and arachnoid) that produces profound motor and sensory blockade is known as spinal anesthesia. The spinal subarachnoid space extends from the foramen magnum to the S2 in adults and S3 in children. Injection of local anesthetic below L1 in adults and L3 (below the termination of the conus medullaris) in children helps to avoid direct trauma to the spinal cord. Ref: Butterwoh IV J.F., Mackey D.C., Wasnick J.D. (2013). Chapter 45. Spinal, Epidural, & Caudal Blocks. In J.F. Butterwoh IV, D.C. Mackey, J.D. Wasnick (Eds), Morgan & Mikhail's Clinical Anesthesiology, 5e.