Local anaesthetic injected directly into the tissue -

Ans. is 'a' i.e., Infiltration anaesthesia Infiltration anaesthesiao It is the injection of local anaesthetic directly into tissue without taking into consideration the course of cutaneous nerve.o It can be so superficial as to include only the skin, it also can include deeper structureso It is used for minor surgeries, e.g. incision & drainage, suturing etc.o Adrenaline can be used along with LA to prolong its duration of action and to prevent its systemic absorptiono However adrenaline containing solution should not be used into tissues supplied by endarteries, e.g. in fingers and toes, ear, nose, and penis because vasoconstriction may lead to gangrene.Conduction blockA. Field blocko Is produced by subcutaneous injection of a solution of local anaesthetic in order to anaesthetize the region distal to the injection.o For example, subcutaneous infiltration of the proximal portion of the volar surface of the forearm results in extensive area of cutaneous anaesthesia that starts 2 to 3 cm distal to the site of injection.B. Nerve blocko LA is injected around a peripheral nerve or a plexus. Examples are -Upper limb - brachial plexus and wrist blockHead & Neck - Stellate ganglion block, trigeminal nerve block.Thorax & abdomen - Interc4ostal nerve & celiac plexuso Note - Most common complication of brachial plexus block is pneumothorax.