o Concepts. Subarachnoid space(csf)subarachnoid block (spinal anesthesia) ● Local anesthesia Epidural space -epidural and caudal anesthesia⚫ Concepts: Subarachnoid space(csf) →subarachnoid block (spinal anesthesia) ⚫ Local anesthesia Epidural space →epidural and caudal anesthesia