1. Good morning

2. RADIAL NERVE
Dr .Qudsia Sultana

3. Objectives Origin Course & Relations Branches Distribution
Applied Anatomy

4. 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
It is primarily a motor nerve

5. Course – RN – Ant.view-Axilla
It commences its decent into the arm by passing anterior to the muscles forming posteerior wall of axilla.

6. Course of Radial Nerve Enters lower triangular interval
Teres major (superior)
Long head triceps (medial)
Humerus (lateral)

7. Course of R N
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

8. Course of Radial Nerve
The lower portion of the radial nerve pierces the lateral intermuscular septum at approximately 8- 12cm from the lateral epicondyle and enters the lower part of arm

9. Course of Radial Nerve
In anterior compartment of arm lies between brachialis medially and brachioradialis, Extensor carpi radialis longus laterally.
In the cubital fossa divide
Superficial radial
Deep radial /Posterior interosseous nerve

11. Course of Superficial Radial Nerve
Runs down the forearm along the lat.border of BR with radial artery on its ulnar side in the middle 1/3 of forearm
Passes posteriorly through tendon of BR proximal to radial styloid.

12. Course of Superficial R.Nerve
Passes over tendons of snuffbox
Terminates as cutaneous branches to dorsum of hand and lateral 3 1/2 digits except nailbeds

14. Course – Posterior Interosseous Nerve
The Post Interosseous Nerve continues down the forearm dividng between the heads of supinator and then emerging to split into several branches that supply the extensors of the wrist and hand

20. APPLIED ANATOMY

21. Lesions Level I – Axilla Level II – Spiral groove Level III – Elbow
Level IV – Forearm

22. Axilla Lesions in the axilla Involves the
posteriorcord / high axillary lesions.
* Etiology:
Crutches / shoulder
dislocation

23. Position Hand hangs in flexion(wrist drop)
Wasting of dorsal arm (triceps)& muscle mass on the posterior surface of the forearm
Paraesthesias & sensory loss on the entire extensor surface of the arm & forearm & on the back of the hand & dorsum of the first 4 fingers.

24. Spiral Groove Sensibility on the extensor aspect of arm is spared .
Etiologies
Humeral factures/Compressive
lesions / Saturday night palsy
Entrapment by tendinous arch
of lateral head of triceps
muscle/damaged after arm
excercise .
Soldiers developing palsies at
the lateral border of humerus
after military shooting training
Sensibility on the extensor aspect of arm is spared .
Sensibility on the extensor aspect of forearm may or may not be spared.
Wrist drop + / No loss of elbow extension

26. Elbow – Radial Tunnel Syn.
Involvement of the Post Interosseous N.
Etiologies
A constricting band at the radiohumeral joint capsule.

27. Position
Atrophy & paresis of the ECU,ED,Extensor digiti minimi APL,EPL,EPB & extensor indices.
Extensor carpi radialis is intact.
Drop finger deformity
Difficulty in extending the MCP of all five fingers
Partial wrist drop
No sensory loss
The wrist deviates radially,when the patient makes a fist.

28. Cheiralgia Paresthetica
The superficial cutaneous branch of the radial nerve → pure sensory syndrome that affects the radial part of the dorsum of the hand & dorsal aspect of the first 3 ½ fingers.
Etiology:
Crushing/twisting injuries of the wrist/forearm
( “Hand-cuff / Wrist watch neuropathy” )
Repetitive pronation & supination.

30. Summary Radial nerve arises from posterior cord of the brachial plexus
It passes posterior to the axillary artery between long and medial heads of triceps muscle, to lie in the spiral groove between medial & lateral heads of triceps muscle.
Here it is accompanied by the profunda brachii artery before it pierces lateral intermuscular septum of the lower third humerus to run between brachialis & brachioradialis
At the lateral of epicondyle humerus, it gives rises to PIN & superficial radial nerve

31. Radial nerve supply all the extensor muscles of forearm & arm
Radial nerve supply all the extensor muscles of forearm & arm. However it also supply brachioradialis, which is flexor of elbow when forearm pronated.
Damage to the nerve in the spiral groove causes
wrist drop but no loss of elbow extension, as fibres of
triceps remain intact proximal to this site.
Only damage in the axilla will causes loss of elbow extension & wrist drop
Damage to posterior interosseus nerve (PIN) does not cause wrist drop because extensor carpi radialis longus receives its innervation from the main radial nerve
Pin only causes inability to extend metacarpophalangeal joint  finger drop.