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

Proximally in the arm, the MC nerve runs in the fascial plane between the coracobrachial and the short head of the biceps brachii muscles

Distally in the arm, the ramifications of the MC nerve run in the fascial plane between the brachialis and the biceps brachii muscles

The MC nerve innervates the flexor muscles of the elbow:

– the coracobrachial muscle

– the biceps brachii muscle

– the brachialis muscle

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

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

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

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

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

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

The ulnar nerve innervates the volar side of the of medial 1 1/2 digits, and it innervates the dorsal side of the medial 2 1/2 digits

The ulnar nerve is a branch of the medial cord of the brachial plexus and contains branches from the ventral rami of the spinal nerve roots C8 and T1

In the proximal 2/3 of the upper limb, the ulnar nerve runs runs in the medial bicipital groove together with the median nerve and the brachial artery and veins; these neurovascular structures are all sandwiched between the triceps brachii and the biceps brachii muscles – and it is anterior to the medial intermuscular septum

Between the middle and distal 1/3 of the arm, the ulnar nerve pierces the medial intermuscular septum and becomes sandwiched between the triceps brachii muscle posteriorly and the brachialis muscle anteriorly and deviates away from the median nerve and brachial vessels which descend postero-medial to the biceps muscle and anterior to the brachialis muscle

In the most distal part of the arm, the ulnar nerve enters the ulnar groove (or sulcus) on the backside of the medial epicondyle of the humerus, while the median nerve and the brachial vessels run anterior to the medial epicondyle