Spinal anaesthesia (or
spinal anesthesia), also called
spinal block,
subarachnoid block (
SAB),
intradural block and
intrathecal block, 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 longer needles are available (12.7 cm / 5 inches). The tip of the spinal needle has a point or small
bevel. Recently, pencil point needles have been made available (Whitacre, Sprotte, Gertie Marx & others).