6 – Sonoanatomy of the axillary brachial plexus block

Visualise the median, ulnar, radial, and musculocutaneous nerves around the pulsatile axillary artery and the veins

If the nerves are invisible they can be traced from the elbow or local anaesthetic can be deposited periarterially.
If a nerve (typically the radial nerve) cannot be visualized, it can be rescue blocked proximal to the elbow.

The median nerve is typically located lateral and superficial in relation to the axillary artery, the ulnar nerve is medial and the radial is deep to the artery. These three nerves typically are sonographically heterogenous. The musculocutaneous nerve is apart from the artery – typically in the fascial plane between the short head of the biceps muscle and the coracobrachialis muscle.

The veins are compressed and become invible when the probe pressure is increased; the blood vessels can be visualised with colour Doppler