Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Spinal anaesthesia (or spinal anesthesia), also called spinal analgesia or sub-arachnoid block (SAB), is a form of regional anaesthesia involving injection of a local anaesthetic into the subarachnoid space, generally through a fine needle, usually 9 cm long (3.5 inches). For extremely obese patients, some anaesthesiologists prefer spinal needles which are 12.7 cm long (5 inches). The tip of the spinal needle has a point or small bevel. Recently, pencil point needles have been made available (Whitacre, Sprotte, & others).