Radial Nerve Anatomy

Originates

- terminal branch posterior cord / C5 - T1

- runs anterior to subscapularis / teres major / lat dorsi

- passes into triangular space (between humerus / long head of triceps / teres major)

- enters posterior compartment of arm

 

Arm

- runs in the radial groove between medial and lateral head of triceps, with profunda brachii

- gives a branch to the long and medial head of triceps (this branch runs with the ulna nerve) before the groove

- also gives the posterior cutaneous nerve of the arm

- in the groove branches to the lateral head  again to the medial head (this branch also supplies anconeus)

- also the lower lateral cutaneous nerve of the arm and the posterior cutaneous nerve of the forearm, which perforates the lateral head

 

Elbow

- passes anteriorly through intermuscular septum

- runs between BR / ECRL laterally and brachialis medially

- supplies these muscles and the elbow joint

- at the level of the lateral epicondyle, the radial nerve divides into superficial branch radial and PIN

 

Superficial branch

- runs under BR until it emerges between it and FCR

- runs superfical to first extensor compartment

- supplies dorsum of hand

 

Supinator

- has superficial and deep layers

- originates from the supinator crest of the ulna

- inserts onto the lateral surface of the radius between the anterior and posterior oblique lines

 

PIN

- passes through the radial tunnel which is between the radiohumeral joint and the distal extent of supinator

- passes under a fibrous band of ECRB

- under the radial recurrent leash of vessels

- into supinator (arcade of Frohse)

- then out from under another fibrous band of supinator

- runs over APL

- dips to run on the interosseous membrane

- ending as a small nodule which supplies the wrist joint

 

PIN then divides

- a superficial branch (supplies EDC, EDM, ECU)

- the deep branch supplies APL, EPB, EI and EPL