Some relative contraindications to consider:

1. Patient needs a neural exam of the affected extremity
2. Anticoagulation use or bleeding disorder (pressure and tourniquet can be applied to the affected area if necessary)
3. Patient with prior neural lesion or active injury

1. Place the patient’s extremity in a partially pronated position, with the hand resting on the hypothenar area and fifth digit.
2. Identify the radial styloid process. Clean and prep the area, then place a skin wheal just dorsal and medial to the radial styloid, at the base of the anatomic snuff box (Figure 2).
3. Insert your needle through your skin wheal and inject 5 mL of local anesthetic subcutaneously in this location.
4. Infiltrate an additional 5 mL of local anesthetic laterally, toward the radial styloid process.

Note: Given the proximity of the radial nerve to the radial artery and the multiple branches that occur at and around the wrist , landmark-based radial nerve block as described below is not recommended as ultrasound localization and a forearm injection site is preferred.

1. Place the patient’s extremity in the supinated position.
2. Using the linear probe, place the US probe on the lateral upper arm. The radial nerve travels in the radial groove of the humerus, then along the lateral aspect in the distal part of the upper arm. Running down the lateral humerus with your probe, you will identify a “honeycomb” hyperechoic structure that moves laterally away from the bone. This is the radial nerve (Figure 3).
3. After cleaning the area and placing a skin wheal, approach the radial nerve from the lateral aspect of the forearm to avoid the radial artery (Figure 4). Advance the needle into vicinity of the radial nerve. Aspirate as you go to avoid intravascular administration and use hydro-dissection to verify appropriate location of the needle tip.
4. Inject 3-5 mL of local anesthetic in the area around the radial nerve.

Note: Another approach is to move your linear probe up from the wrist crease. The radial artery is easily identified here and the radial nerve will be found in close proximity. As you move up the forearm the nerve will separate from the artery (Figure 5).

1. Radial nerve block is safe and effective way to provide analgesia/anesthesia to a patient requiring intervention (i.e. laceration repair) in the dermatomal distribution of the radial nerve.
2. Very few contraindications exist for this block (overlying infection, medication allergy).
3. The radial nerve can be injected blindly at the base of the anatomic snuff box dorsal to the radial styloid process, or via ultrasound in the distal upper arm.

• Radial nerve block is safe and effective way to provide analgesia/anesthesia to a patient requiring intervention (i.e. laceration repair) in the dermatomal distribution of the radial nerve.
• Very few contraindications exist for this block (overlying infection, medication allergy).
• The radial nerve can be injected blindly at the base of the anatomic snuff box dorsal to the radial styloid process, or via ultrasound in the distal upper arm.