LKnative - Radial nerve block 
Radial nerve (blue arrow), posterior antebrachial cutaneous nerve (orange arrow), deep branch (cyan arrow), superficial branch (black arrows), posterior interosseseous nerve (red arrow), brachioradialis (blue asterixs), brachialis (red asterix), supinator (green asterix), the pollicis muscles (magenta, black and cyan asterixs)
5 – Anatomy: The lower part of the radial nerve
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