Infraclavicular Nerve Block Technique

Updated: Sep 06, 2018
  • Author: Alma N Juels, MD; Chief Editor: Meda Raghavendra (Raghu), MD  more...
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Needle Placement – Ultrasound Guidance

For the proximal approach, place the transducer parallel and below the midpoint of the clavicle. Most medial will be the axillary vein; the axillary artery is next in the center, and the brachial plexus divisions are most lateral. The needle is advanced in or out of the plane. The best view is obtained going from lateral to medial, keeping the needle in plane; the needle can then be viewed along its entire path. [1]

For the coracoid approach, the ultrasound probe is placed close to the coracoid seeking the optimal image of the axillary artery with the surrounding nerves. The probe may need to be rotated to obtain optimal view of plexus, which is diagonally in the infraclavicular area. The nerve bundle is deeper with the coracoid approach, requiring a steep angle of 45°, making visualization of the needle difficult. Also, a wide anatomic variation of the cords in this region exists, and even only 2 cords can exist instead of 3. Arm abduction is recommended to stretch the cords, bringing them closer together and more anterior, making it easier to see and block.

This block can be done with a lateral to medial approach or a cephalad to caudad approach. [5]

The cephalad-to-caudad approach. The cephalad-to-caudad approach.


Ultrasound image of the needle in plane with local Ultrasound image of the needle in plane with local anesthetic posterior to the axillary artery. Arrows = block needle, AA = axillary artery, LA = local anesthetic posterior to the artery.

The aim with both approaches is to get local anesthetic around all cords; this is best accomplished by injecting posterior to the axillary artery and getting a U-shaped spread around the artery. Maximum block success is best accomplished by injecting 10 mL posterior to the artery, 6 o'clock, to get the posterior cord. For the lateral cord, withdraw the needle slightly and aim for the 9 o'clock position around the artery and inject another 10 mL of local anesthetic. This should get a good spread around the artery. If the 3 o'clock position around the artery looks like it did not get a good spread of local anesthetic, injecting some local anesthetic in that area (between the axillary artery and vein where the medial cord lives) may be necessary, although it is usually not necessary. This results in 20–30cc total volume injected. Usually less is needed if a circumferential spread is obtained with the first two injections-posterior cord and lateral cord spreading to the medial cord. [4]  Keep the image of the nerve bundle centered. If it is difficult to visualize the needle, rock the probe slowly until the needle can be seen. Inject slowly without too much pressure.

Ultrasound orientation of the muscles, arteries, a Ultrasound orientation of the muscles, arteries, and nerves in a transverse view. Short axis (transverse view)-AA=axillary artery, Arrowheads=cords, AV=axillary vein, PMM=pectoralis major, PMIM=pectoralis minor 9-12 o‘clock is cephalad to artery=lateral cord, 6-9 o'clock is posterior=posterior cord, 3-6 o'clock is caudad is medial cord. Medial cord is often hard to visualize.

Nerve Stimulator for Infraclavicular Block

The patient is supine, shoulder down, and the arm is abducted 30–45°. This moves the neuromuscular bundle away from the thoracic cage, which decreases the chance of a pneumothorax. Palpate the coracoid process; the needle is inserted 2 cm caudal and 2 cm medial to the coracoid process. The needle is attached to the nerve stimulator and advanced in the anteroposterior direction. The needle first passes through the pectoralis muscles, major and minor, producing a visible twitch. Continue deeper to get to the brachial plexus. If no twitch is obtained, usually redirecting caudally but occasionally cephalad will locate the nerve trunk. You are looking for finger twitching. 



The following complications may occur:

  • Muscle pain from needle insertion through the pectoralis major and minor can occur.

  • Gemstones can be large once again due to the muscle penetration.

  • Hematomas can occur. To reduce the likelihood of a hematoma, avoid multiple needle insertions and apply firm pressure after removing needle. Consider risk/benefit in patients undergoing coagulopathy.

  • Pneumothorax is possible but extremely rare; it is not as high a risk as with interscalene or supraclavicular blocks because the needle is advanced away from the chest cavity.

  • Nerve injury is always a possibility with nerve blocks. Avoid contact with the nerve bundles, and advance needle slowly. Stop when a "pop" is felt entering the nerve sheath. Do not inject if high pressure is felt. Do not inject if the patient experiences pain. Readjust the needle when the above scenarios are experienced. Most of the time, the needle needs to be withdrawn slightly. This is an extremely rare complication.

  • Toxicity can once again occur with any block, and intravascular injection needs to be prevented. Aspirate every 3–5 mL. Inject slowly to avoid injecting local anesthetics into smaller vessels and lymphatics that have been punctured during needle insertion.

  • Infection is avoided by using strict aseptic technique


Approach Considerations

It is unusual to only use a nerve stimulator unless you do not have an ultrasound available or have not been trained to use the ultrasound. Nerve stimulation is uncomfortable for the patient. 

If the image is poor or you want to use less volume, it is helpful to use both the ultrasound and the nerve stimulator. Using the ultrasound will allow you to visualize the needle in the correct area and the nerve stimulator will allow you to optimize the exact location to inject the local anesthetic. This is especially helpful if the anatomy is distorted or the view is poor.

A randomized comparative study showed fewer complications when the ultrasound and nerve stimulator where both used. [7]

Studies comparing the ultrasound guided technique alone and the nerve stimulator technique alone have shown ultrasound guidance to be superior as far as procedural time, quality of the block, and vascular complications. [8]

Most anesthesiologists today use the ultrasound alone without the nerve stimulator.