A metacarpal block is the anaesthetising of the fingers distal to the metacarpals in the hand.
The patient is prepared by placing the hand flat and spreading the fingers. The position of the metacarpal heads on the dorsum of the hand is marked. A needle is advance directly between adjacent metacarpus downwards until it can be felt subcutaneously on the palmar surface of the hand. The needle is withdrawn slowly and 2-3 ml of 1% lignocaine is injected.
Vasoconstrictive agents such as adrenaline must never be used for metacarpal blocks as there is a risk of digital necrosis.