Training in Anaesthesia Highlands of Scotland

Resources suggested by Dr Pietersen, thankyou. Starting with @KiJinnChin :

Considerable anatomic variation is noted for all the terminal branches of the brachial plexus; however the most common orientations are: 

Median Nerve – anterior lateral to the artery (above and slightly left, at the 10 to 12 o’clock position relative to the artery) 

Ulnar Nerve – anterior medial to the artery (above and to the right, near the axillary vein, 1-3 o’clock position relative to the artery) 

Radial Nerve – posterior medial to the artery (below and to the right, between 3 to 6 o’clock positions relative to the artery) 

Musculocutaneous Nerve – optimal imaging requires more lateral positioning of the transducer as it lies within the coracobrachialis muscle or fascia just below the biceps muscle 

This image from NYSORA

FIGURE 1. (A) Cross-sectional anatomy of the axillary fossa and ultrasound image (B) of the terminal nerves of brachial plexus. The BP is seen scattered around the axillary artery and enclosed within the adipose tissue compartment containing the axillary artery (AA), and axillary veins (AV). MCN, musculocutaneous nerve. MN, median nerve; RN, radial nerve; UN, ulnar nerve; MACN, medial antebrachial cutaneous nerve; CBM, coracobrachialis muscle 

Supplemental Nerve Blocks 

• Musculocutaneous nerve block can be performed by injecting 5-10 mL of local anesthetic into the body of the coracobrachialis muscle in a fanlike manner in a lateral to medial plane.  This technique is indicated if the musculocutaneous nerve is not identified by nerve stimulation/ultrasound or if a transarterial approach is used.  
• Intercostobrachial and medial brachial cutaneous nerve block helps to prevent tourniquet-related pain because the intercostobrachial nerve (T2) joins the medial brachial cutaneous nerve to innervate the skin of the upper half of the medial and posterior part of the arm.  At the site of needle insertion, 5-8 mL of local anesthetic is injected subcutaneously across the axilla both superior and inferior to the artery. The intercostobrachial nerve may be seen on ultrasound imaging, and does not always need a separate supplemental block if performed proximal enough or viewed on ultrasound. 

This from USRA.CA

This from the BJA in 2018