radial nerve entrapment

Radial tunnel syndrome

definition

· symptoms and signs from entrapment of posterior interosseous nerve from radial head to supinator muscle

aetiology

Sites of compression

Entrance to tunnel

· fibrous bands anterior to radial head

Henry’s recurrent leash

· fan-shaped leash of vessels over nerve

· radial recurrent

· supply BR and ECRL

ECRB

· tendinous margin

Arcade of Frohse

· most common

· ligamentous band at margin of supinator

Supinator

· fascial arcade along distal lateral border

clinical

History

· aching pain in extensor-supinator muscle mass in proximal forearm

· radiates to distal arm and forearm

Examination

· weakness or paralysis of wrist and finger extensors

· no sensory disturbance

· provocative test

· supination with flexed elbow

investigations

Electrodiagnostic studies

· denervation of radially innervated muscles

differential diagnosis

Tennis elbow

· tenderness at lateral epicondyle cf. supinator

· positive middle finger sign

treatment

· exploration of nerve in radial tunnel

· anterolateral approach