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. Infraclavicular Brachial Plexus Block. The Internet Journal of Anesthesiology. 1999 Volume 5 Number 1.
With the patient in the supine position, the block is best performed with the arm abducted at 90° angle and the patient’s head facing away from the arm to be anesthetized (Figure 1).
The following anatomical landmarks are identified and marked:
Medial head of the clavicle
The midpoint between the points 1 and 2. (mid-point of the clavicle)
The anesthesiologist stands at the opposite site to be blocked. The needle is inserted 2 cm below the midpoint of the clavicle and directed toward the axillary artery (Figures 2,3,4).
With this approach, the needle commonly assumes an angle of 60° to the skin plane. The needle is slowly advanced until the twitches from hand or forearm are obtained (Figure 5).
The initial current of 0.6-0.8 mAmps is decreased to below 0.3 mAmps at which point 40 -50 ml of local anesthetic is injected (Figure 6).
Success rate rapidly decreases with current above 0.3 mAmps
Twitches from biceps muscle should not be accepted, since the musculocutaneous branch may be outside the brachial sheath.
When the initial stimulation is that of the axillary nerve (deltoid muscle twitch) or of the musculocutanous nerve (biceps muscle), the needle should be redirected inferiorily (Figure 7).