Nerve blocks are used to isolate a source of pain that may be resulting in, for example lameness. Local anaesthetic is injected into various areas and which are then “numbed”. These specific regions may include joints or where nerves lie close to the skin. Based on the horse’s response to this numbing it can be ascertained whether the horse was painful or not before the injection and therefore whether that area is injured. For example during an examination of a lame horse, nerve blocks may be used to numb the foot. If the horse subsequently trots up sound then it can be said that the area of injury is in the foot. Typically the blocks are started at the lowest points, working up the limb to isolate the area of pain.