Rothe C, Asghar S, Andersen HL, Christensen JK, Lange KHW: Ultrasound-guided block of the axillary nerve: a volunteer study of a new method. Acta Anaesthesiol Scan 55:565-570 (2011)

S

– Haematoma

– Nerve injury

Axillary nerve block does NOT produce the typical side effects and complications of the interscalene brachial plexus block.

Rescue block of the radial nerve when it is not blocked as part of a supra- or infraclavicular block or an axillary brachial plexus block

The radial nerve exit the axilla via the triceps triangle together with the deep brachial artery (profunda brachii artery)

The “triceps triangle” is a window delineated by the teres major muscle superiorly, the long head of the triceps brachii medially and the humerus laterally (see next page)

The radial nerve is a branch of the posterior cord. It typically contains nerve fibres from the ventral rami of the spinal nerve roots C6-T1

Postoperative analgesia after shoulder surgery in combination with a suprascapular nerve block as an alternative to interscalene brachial plexus block

The axillary and radial nerves origin from the posterior cord of the brachial plexus

The axillary nerve contains nerve fibres from the ventral rami of the C5 and C6 spinal nerve roots

The axillary nerve branches off the posterior cord of the brachial plexus at the lower border of the subscapularis muscle and runs posteriorly through the “quadrangular space” bounded by the surgical neck of the humerus, the tendon of the triceps brachii (long head) muscle, the teres major muscle and the subscapularis muscle

The axillary nerve joins the posterior circumflex humeral artery and vein through the window of the quadrangular space (see next page)

In the parasagittal plane below the surgical neck of the humerus, the axillary nerve is visualized between the shaft of the humerus and the deep side of the fascia of the deltoid muscle and just distal to the cross-sectional view of the teres minor muscle and just cranial to the adjacent pulsatile posterior circumflex humeral artery

Sometimes the axillary nerve is not visible sonographically. In that case ultrasound and electrical nerve stimulation can be combined in order to identify the exact location of the target nerve

Ref. Rothe et al. (2011)

The axillary nerve splits in an anterior and a posterior branch inside the “window” of the quadrangular space or a bit more distal inside the deltoid muscle (which is removed in the picture on the right)

The axillary nerve (or sometimes a branch from the posterior cord of the brachial plexus) innervates:
– the triceps brachii (long head) muscles (ref. S

Place the patient in the sitting position with the humerus rotated 45 degrees internal and the elbow flexed 90 degrees and the hand resting on the thigh

Place the high-frequency linear probe in the parasagittal plane along the long axis of the humerus distal to the postero-lateral margin of the acromion

Identify the surgical neck of the humerus and the crossing pulsatile posterior circumflex humeral artery (use color or power Doppler) and the adjacent axillary nerve or its anterior branch (see next page)

Insert the needle with in-plane technique from the cranial end of the probe

Penetrate the fascia of the deltoid muscle and place the needle tip just cranial to the posterior circumflex humeral artery

Inject 5-10 mL of local anaesthetic until complete perineural spread is obtained