Which of these statement(s) is/are correct regarding subcutaneous infiltration?I. It may be used to infiltrate anesthetic into the cerebrospinal fluidII. Aspiration is not necessary as there are relatively few blood vessels at this levelIII. It aims to block large nerve axonsIV. It may form a visible wheal.

The correct statements regarding subcutaneous infiltration are:

III. It aims to block large nerve axons: This is correct. Subcutaneous infiltration is a type of local anesthesia that works by blocking nerve signals in your body. This numbs a small area of your body and helps to manage pain during minor surgical procedures.

IV. It may form a visible wheal: This is also correct. When the anesthetic is injected into the subcutaneous tissue, it may cause a visible wheal or raised area on the skin.

The incorrect statements are:

I. It may be used to infiltrate anesthetic into the cerebrospinal fluid: This is incorrect. Subcutaneous infiltration involves injecting the anesthetic into the subcutaneous tissue, which is the layer of fat and connective tissue that lies immediately under the skin. It does not involve infiltrating anesthetic into the cerebrospinal fluid.

II. Aspiration is not necessary as there are relatively few blood vessels at this level: This is also incorrect. Aspiration, or pulling back on the syringe before injecting, is often done to ensure that the needle is not in a blood vessel. Even though there are fewer blood vessels in the subcutaneous tissue compared to other areas, there is still a risk of intravascular injection, which can cause complications. Therefore, aspiration is often recommended.