The No. is an elongated triangular blade sharpened along the hypotenuse edge with a strong pointed tip making it ideal for stab incisions needed when lancing an abscess or inserting a chest drain. It is held like a pencil and often upside down by the surgeon to prevent it inadvertently being inserted too deep. To avoid this scenario the scalpel should not be held towards the back end whilst the heel of the hand should be placed on the skin thus stabilising the hand to help prevent an unwanted deep incision.