Radial nerve-anatomy


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Radial nerve-anatomy

  1. 1. Radial Nerve Anatomy Episode 1
  2. 2. Radial Nerve• Originates as the terminal branch of the posterior cord of the brachial plexus: – roots from C5, 6, 7, 8, & T1. – Largest branch of brachial plexus
  3. 3. Cutaneous Innervation• Posterior cutaneous nerve of arm• Inferior lateral cutaneous nerve of arm• Posterior cutaneous nerve of forearm• Superficial branch of radial nerve
  4. 4. Motor Innervation• Muscular branches of radial nerve above elbow: – Triceps – Anconeus – Brachoradialis – ECRL
  5. 5. Motor Innervation• Muscular Branches below elbow: – ECRB (varied innervation: superficial or PIN) – Supinator• PIN: – Superficial • EDC, ECU,, EDM – Deep • APL, EPL, EPB, EI
  6. 6. Course of Radial Nerve
  7. 7. Course of Radial Nerve• Largest terminal branch of posterior cord• Enters posterior aspect of humerus through lower triangular interval – Teres major (superior) – Long head triceps (medial) – Humerus (lateral)• Gives posterior cutaneous nerve of arm in axilla
  8. 8. Course of Radial Nerve• Comes to lie in distal part of spiral groove with profundi brachii artery – Beneath lateral head of triceps and proximal to origin of medial head• Gives branches to triceps, anconeus and inferior lateral cutaneous nerve of arm• Through lateral intermuscular septum 10-12cm above lateral epicondyle
  9. 9. Course of Radial Nerve• In anterior compartment of arm lies between brachialis and brachioradialis – 1-3 accessory branches to brachialis – Large branch to BR (sometimes this branch given by superficial radial below elbow)• ECRL generally innervated proximal to elbow joint
  10. 10. Course of Radial Nerve• Enters the forearm anterior to lateral epicondyle – More specifically over articulation between capitulum and radial head• ECRB innervated distal to elbow joint either PIN or superficial branch• At some point 3cm above or below divides into: – Superficial radial – PIN
  11. 11. Course of Superficial Radial Nerve• Runs over supinator,PT and FDS• Lies under BR with radial artery on its ulnar side from 1/3 of the way down forearm• Passes posteriorly through tendon of BR proximal to radial styloid• Passes over tendons of snuffbox• Terminates as cutaneous branches to dorsum of hand and lateral 3.5 digits short of nailbeds
  12. 12. Posterior Interosseous Nerve• Gains access to posterior forearm by diving posterior and laterally through ligament of Frohse and the interval between the two heads of supinator• Arcade of Frohse is a fibrous arch originating lateral epicondyle superior part of superficial layer of supinator – German Anatomist, Fritz Frohse (1871-1916)
  13. 13. Posterior Interosseous Nerve• After exiting the supinator divides into deep and superficial muscular branches – Superficial • EDC, ECU, EDM – Deep • APL, EPL, EPB, EI
  14. 14. Radial Nerve Compression Sites• PIN – As it traverses the radial tunnel it encounters 4 sites of compression – “Radial tunnel syndrome” • entrapment neuropathy
  15. 15. Radial Tunnel Syndrome1. Fibrous bands • Tight fibrous bands anterior to radial head at entrance of tunnel1. Arcade of Frohse • Most common1. Leash of Henry • Radial recurrent vx that fan out over radial nn1. Medial border of ECRB
  16. 16. Cheiralgia paresthetica• Described by Robert Wartenberg 1932• Superficial radial nerve neuritis – Wartenberg Syndrome• Causes: – Trauma, iatrogenic, compression (muscle anomalies, fascial bands, thrombosis radial recurrent artery, tumour, haemorrhage)• Symptoms: – Dysaesthesia over distribution
  17. 17. Radial Nerve Palsy• Causes: – Fractures esp humerus, Monteggia – Penetrating injury/trauma – “Saturday Night Palsy” “Crutches” – Iatrogenic – tumour
  18. 18. Episode IIRadial Nerve Tendon Transfers