Infraclavicular (Sagittal Approach)

The infraclavicular block is used to provide anesthesia and analgesia for procedures involving the distal upper arm, elbow, forearm, wrist and hand. This block is aimed at anesthetizing the medial, posterior, and lateral cords of the brachial plexus, which are situated posterolateral to the distal subclavian artery.  Because of the distance of the cords relative to the phrenic nerve, paralysis of the diaphragm is unlikely, making this an option for patients with severe respiratory disease.  However, the divergent arrangement and depth of the cords at this level may make complete anesthesia more difficult to accomplish than a supraclavicular block.

Indications: surgeries of the upper extremity, excluding the shoulder

Patient Position: patient is supine with their arm relaxed at the side

Transducer: Low-to-mid frequency transducer (5-7MHz) dependent on the patient’s body habitus

Transducer Position: Placed in a sagittal orientation at the distal clavicle, medial to the coracoid process

Needle: 5-10cm, 18-22 gauge stimulating needle (A larger bore needle may be preferred for needle visualization)

Local Anesthetic: 30-40mls of local anesthetic

Keys To A Successful Block: the goal is place local anesthetic around the cords of the brachial plexus.  Experience has shown that injecting the first 10-15ml of local anesthetic around the posterior cord (six o’clock position), then redirecting the needle toward the lateral cord at the nine o’clock position will provide better results.

Infraclavicular US with transducer placement

The patient is placed in the supine position with the arm either resting by the side (below left) or abducted with the elbow flexed, with the practitioner standing at the head.  The cords of tend to lie deeper than at other positions along the brachial plexus, with studies showing the average depth of the cords between 4-4.5cm.  They appear hyperechoic around the distal subclavian artery.  However, it is important not to confuse them for acoustic enhancement that can occur under the vessels (red arrows).  The increased depth may require a lower frequency transducer, such as a 5-7MHz transducer.  Because a successful procedure requires the needle to pass through two large muscle groups (pectoris major and minor), a subcutaneous injection of local anesthetic at the cephalad end of the transducer will not only anesthetize the area, but also provide a track for the block needle.  It is often possible to use a 5cm, 22gauge stimulating needle, however a larger gauge (such as an 18 gauge Tuohy) may offer better visualization for the in-plane approach used to accomplish this block.  The needle is passed in-plane in a cephalad to caudal direction with continual visualization.

The pleura is located posterior and medial to the cords of the brachial plexus.  Slight rocking of the transducer medially (image below) reveals the closeness of the pleura in relation to the plexus at this level.  Continual visualization of the needle during this procedure is vital to preventing a possible pneumothorax.


Mulroy MF, Bernards CM, McDonald SB, Salinas FV. A Practical Approach to Regional Anesthesia. 4th. Ed. Baltimore, MD: Lippincott Williams and Wilkins; 2009:174, 188-192.

Chan VW, Abbas S, Brull R, et al. Ultrasound imaging for regional anesthesia; a practical guide. 3rd ed. Toronto. Toronto Printing Company; 2010:74-81.

Pollard BA, Chan VW. An introductory curriculum for ultrasound-guided regional anesthesia: a learner’s guide. Toronto. University of Toronto Press Inc.; 2009:61-63.

Gray AT. Atlas of ultrasound-guided regional anesthesia. Philadelphia, PA. Saunders, Elsevier; 2010:92-95.

Bigeleisen PE, ed, Orebaugh SL, Moayeri N, et al. Ultrasound-guided regional anesthesia ad pain medicine. Baltimore, MD. Lippincott Williams & Wilkins; 2010:58-64.




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