Axillary nerve block
The classical axillary blockade of the brachial plexus is performed in an area in which cords have already formed the peripheral nerves of the arm. The axillary nerve and musculocutaneous nerve (which contains the fibres of the lateral cutaneous nerve of the forearm) emerge from the plexus above the puncture site. This is one reason why troublesome gaps can occur in the radial lower and upper arm. Despite this, the axillary nerve block is a widespread technique because it is simple to use and has few complications.
Ultrasound-guided axillary nerve block
Through the use of ultrasound it is almost always easily possible to visualize the 4 main nerves and then irrigate them with local anaesthetic. It is not without reason that one can speak in this area of an individual nerve block rather than a plexus block. The axillary artery and the axillary vein, along with the fascia of the triceps arm muscle, serve as anatomic landmarks. Worthy of note is the enormous anatomic variability of nerves and blood vessels in this region.