The musculocutaneous (MC) nerve is a sensori-motor nerve that originates from the lateral cord of the brachial plexus at the infero-lateral margin of the minor pectoral muscle

It follows the axillary artery for a short distance before it deviates laterally and pierces the coracobrachial muscle or enters the fascial plane between this muscle and the short head of the biceps brachii muscle

Often the MC nerve enters this fascial plane directly from medial to lateral without piercing the coracobrachial muscle

The lateral antebrachial cutaneous (LAC) nerve pierces the deep fascia immediately after its exit from the lateral margin of the biceps brachii and brachialis muscles

The LAC nerve runs deep to the cephalic vein and splits into a ventral and a dorsal branch that innervate the ventral and dorsal surfaces of the radial margin of the antebrachium from the elbow to the wrist

The ulnar nerve can be blocked with ultrasound guidance 5-10 cm proximal to the elbow crease just proximal to the medial epicondyle, where the ulnar nerve is located very superficially just below the deep fascia

Rescue analgesia of the musculocutaneous nerve, when it is failed as part of a supra- or infraclavicular or axillar brachial plexus block

The musculocutaneous nerve originates from the lateral cord of the brachial plexus and receives nerve fibres – via the anterior divisions of the superior and the medial trunks – from the anterior rami of the spinal nerve roots C5-C7

Place the patient supine with the arm abducted and flexed 90 degrees at the elbow

Place the probe axially visualizing the ulnar nerve in cross-sectional view (see next page)

The ulnar nerve can be visualized in the ulnar sulcus and tracked proximally – it should not be blocked inside the sulcus due to risk of compression injury

Insert the needle from the lateral end of the probe and advance the needle in-plane

Inject local anaesthetic 3-5 mL perineurally

It is also possible to block the ulnar nerve at the midarm level in the medial bicipital groove, where the ulnar nerve runs close together with the brachial artery and veins and the median nerve

The cutaneous somato-sensory innervation of the hand follows the ulnar innervation of the bones (see previous page)

The ulnar nerve originates from the medial cord of the brachial plexus

The medial cord is derived from the anterior division of the inferior trunk, which is derived from the ventral rami of the spinal nerve roots of C8 and T1

Rescue blockade when analgesia of the ulnar nerve territory is failed after supra- or infraclavicular or axillary brachial plexus block

Isolated surgery on the fifth digit