Axillary Brachial Plexus Block


Anatomical Target, Coverage

The brachial plexus can be approached at different levels along its course, from individual nerve roots soon after exiting the spine to discreet nerves more distal along its course.  The axillary brachial plexus block, so called because of the proximity of the brachial plexus to the axillary artery, targets individual nerves of the plexus as they pass near the axillary artery in the groove between the deltoid and biceps brachii. The block targets the musculocutaneous, median, ulnar, and radial nerves.  Not specifically targeted, but invariably blocked, is the medial antebrachial nerve which tends to travel with the median nerve.  Together, these nerves provide complete coverage distal to elbow.  Nerves less likely to be blocked include the axillary nerve, medial brachial cutaneous and the intercostobrachial. 


Clinical Use: 

The axillary brachial plexus block is excellent for all indications distal to the elbow. Because the axillary brachial plexus block unreliably achieves blockade of the axillary, medial brachial cutaneous, or intercostobrachial nerves, it will not provide adequate coverage proximal to the elbow.

Block Technique

The axillary brachial plexus nerve block is performed in the muscular groove inferior to the anterior deltoid and superior/medial to the biceps brachii. Typically, patients are positioned supine with the ipsilateral hand placed behind or next to the head which exposes the axillary fossa. First, the arm is prepped in a sterile fashion, anatomy is then identified with an ultrasound and the block needle entry site and pathway anesthetized with injection of approximately 2-5cc of 2% lidocaine. Then a 21 or 22 gauge short-bevel needle is advanced with an in-plane technique and local anesthetic deposited individually around each of the four target nerves (musculocutaneous, median, ulnar and radial).

Block Duration 

The Duration of a single injection of approximately 20-25cc of 0.5% ropivacaine is ~9-12 hours. However, the duration of the block is variable (5-25hours) depending on individual characteristics and which local anesthetic is chosen.

While it is possible to place a catheter for continuous infusion of local anesthetic, there is some concern about adequate coverage, early catheter displacement and increased risks of infection.  While the median, ulnar, and radial nerves travel in close proximity to the axillary artery, the musculocutaneous nerve is separate (traveling between the biceps brachii and the coracobrachialis) and may not be covered.  Additionally, the nerves are quite superficial at this level, and therefore, there is less anchoring tissue to maintain catheter placement.  Therefore, for prolonged coverage, please consider the infraclavicular block as an alternative.

Special Considerations: 

Contraindications, Side Effects, Complications:

Generally considered the safest brachial plexus block because of the distance from the phrenic nerve and absent risk of pneumothorax.  There is still the risk of intraarterial injection (minimized by careful technique) and nerve injury from direct trauma or intraneural injection, although these are also present with the other brachial plexus blocks.

General contraindications to regional anesthesia also apply.  Patient refusal is an absolute contraindication.  Patients on therapeutic anticoagulation or with significant coagulopathies, infection at the site of injection, and preexisting nerve injury in the block distribution are relative contraindications.


Satapathy, A. R. & Coventry, D. M. Axillary Brachial Plexus Block. Anesthesiol Res Pract 2011, 173796 (2011). 

Sariguney, D., Mahli, A. & Coskun, D. The Extent of Blockade Following Axillary and Infraclavicular Approaches