Rescue analgesia of the median nerve when a supra- or infraclavicular or an axillary brachial plexus block has failed to block this nerve

The median nerve origins from the lateral and medial cords of the brachial plexus

The median nerve contains nerve fibres from the ventral rami of the spinal nerve roots C6-T1

The periosteal innervation of the radial nerve is:

– the proximal humerus distal to the surgical collum

– the lateral epicondyle of the humerus

– the anterior aspect of the proximal radial head

– the dorsal side of the radius and ulna

– the dorsal side of the radial 2 1/2 digits and metacarpal bones (see next page)

– a variable part of the anterior side of the wrist bones (see next page)

The deep branch of the radial nerve becomes the posterior interosseous nerve of the forearm. This nerve innervates the following muscles:

– the supinator

– the extensor digitorum & extensor digiti minimi

– the extensor carpi ulnaris

– extensor pollicis longus & brevis

– extensor indicis

– abductor pollicis longus

The radial nerve can be blocked where it crosses the lateral epicondyle sandwiched between the brachioradial and the brachialis muscles

The radial nerve innervates the dorsal side of the wrist bones and the 2 1/2 radial digits – except for the distal dorsal parts of the second and third finger which is innervated by the median nerve

A variable part of the anterior side of the wrist bones is innervated by the radial nerve

The radial nerve descends in the posterior compartment of the arm in the humeral sulcus (= the spiral or radial groove of the humerus)

When it emerges from the lateral end of the sulcus it pierces the lateral intermuscular septum and enters the anterior compartment of the arm

Here it descends between the brachial and brachioradial muscles across the lateral epicondyle of the humerus to the forearm

In the forearm the radial nerve splits into a deep motor branch and a superficial sensory branch

The deep branch pierces the supinator and coils around the radius to become the “posterior interosseous nerve of the forearm”

The superficial branch descends in the forearm deep to the brachioradial nerve

A posterior view of the forearm is shown on the right; the medial epicondyle is marked with a green arrow

The cutaneous branches of the radial nerve are:

The posterior brachial cutaneous nerve innervates the posterior aspect of the arm down to the olecranon

The inferior lateral brachial cutaneous nerve innervates the inferior lateral part of the arm at the level of the elbow

The posterior antebrachial cutaneous nerve innervates the posterior part of the forearm

The superficial branch of the radial nerve runs in the forearm deep to the brachioradial muscle and lateral to the radial artery

Approx. 6 cm proximal to the wrist it pierces the deep fascia and bifurcates in a medial and a lateral branch that innervate the dorsal part of the 2 1/2 radial digits

The radial nerve supplies motor branches to:

– the lateral and medial heads of the triceps muscle

– the anconeus muscle

– the brachioradial muscle

– the extensor carpi radialis longus muscle

The motor branches from the deep branch of the radial nerve are presented on the next page