In spinal anesthesia the drug is deposited between?

ANSWER: (A) Pia and arachnoidREF; Fundamentals of Anesthesia, Tim Smith Colin Pinnock Ted Lin, 3rd Edition, p 118Spinal anesthesia requires the injection of a small volume of local anesthetic agent directly into the cerebrospinal fluid (CSF) in the lumbar region, below the level of Ll/2, where the spinal cord ends.A line joining both iliac crests (Tuffiers line) passes across the spine of L4 and is a reliable landmark for locating the L3/4 interspace, which is the L3/4 interspace, which isusually easily defined and is the one most often used.Method: Sterilize the skin over the lumbar spine and raise a skin weal with lidocaine 1% over the appropriate interspace. Inject 2-3 ml more lidocaine into the subcutaneous tissue. Insert the needle or introducer in the midline at 90 degrees to the skin.Feedback from the needle tip will monitor the progress of the needle through the supraspinous and interspinous ligaments, the ligamentum flavum and sometimes the dura mater. If bone is contacted, withdraw the needle to the subcutaneous tissue and redirect slightly cephalad in the first instance.Puncture of the dura is usually obvious, and when the stylet is removed CSF should flow freely.