Radial, ulnar and median nerve injuries

Radial, ulnar and median nerve course and injuries

1. Radial,Median and Ulnar nerve injuries Dr. Debesh Shrestha Resident of Orthopaedics GMC

2. Radial nerve C5,C6, C7, C8, T1 It is the terminal branch of the posterior cord of the brachial plexus

3. Course In the axilla I t lies anterior to the subscapularis , teres major and lattismus dorsi muscle Motor supply to the long head of triceps Posterior cutaneous nerve of arm

4. In the arm Lies in the spiral groove of humerus Re-enters anterior compartment by piercing lateral intermuscular septum Motor supply to triceps (medial and lateral head), anconeus , brachialis , brachioradialis , extensor carpi radialis longus Sensory : lower lateral cutaneous nerve of arm posterior cutaneous nerve of forearm

5. In the elbow Anterior to the lateral epicondyle , radial nerve divides into the terminal branches : Posterior interosseus nerve Superficial radial sensory nerve

6. In the forearm PIN reaches the back of the forearm by passing round lateral aspect of the radius between the two heads of supinator As it emerges from the supinator posteriorly , the nerve at first lies between the superficial and deep extensor muscles. At the distal border of extensor pollicis brevis , it passes deep to extensor pollicis longus and diminished to a fine thread, descends on the interosseus membrane to the dorsum of the carpus - supply carpal ligaments and articulations

7. PIN supplies Extension carpi radialis brevis Supinator Extensor digitorum Extensor digiti minimi Extensor carpi ulnaris Abductor pollicis longus Extensor pollicis longus Extensor pollicis brevis Extensor indicis

8. Radial nerve injury Very high– above the spiral groove crutch palsy Saturday night palsy Trauma/operations around the shoulder 2. High – at or below the spiral groove Fracture shaft of humerus Prolonged torniquet pressure

9. 3. Low– at or below the elbow PIN injury– radial tunnel syndrome fractures ( monteggia fracture) iatrogenic superficial radial nerve injury fracture iatrogenic (venous canulation ) Laceration Blunt trauma

10. Clinical features Very high radial injury– weak elbow extension loss of wrist, finger and thumb extension (wrist drop) Sensory loss over the posterior arm, forearm and posterolateral hand High radial injury Normal elbow extension Loss of wrist, finger and finger extension Normal sensation over posterior arm and forearm Sensory loss over posterolateral hand

11. Low radial injury Posterior interosseus nerve injury Normal elbow and wrist extensors Weak finger and thumb extensors Normal sensation over posterior arm, forearm and posterolateral hand Superficial radial nerve injury Normal extensors Sensory loss over posterolateral hand Normal sensation over posterior arm and forearm

12. Wartenberg syndrome Compression of superficial branch of radial nerve between ECRL and brachioradialis Numbness over posterior aspect of thumb

13. Radial tunnel syndrome About 5 cm space Dorsally– capsule of the radiocapitellar joint Volarly – brachioradialis Laterally– ECRB and ECRL Medially– biceps tendon and brachialis PIN nerve compressed C/F– loss of finger and thumb extension, weak wrist extension

14. Median nerve Roots from the lateral ( C5, C6, C7) and medial ( C8, T1) cords unite to form the median nerve In the axilla – no branches In the arm– descends along the lateral side of the 3 rd part of the axillary artery and brachial artery Near the insertion of the coracobrachialis , it crosses in front of the brachial artery from lateral to medial side

15. In the cubital fossa Lies medial to the brachial artery Covered by bicipital aponeurosis

16. In the forearm Enters forearm between the two heads of pronator teres Passes beneath the arch of flexor digitorum superficialis Runs between flexor digitorum superficialis and flexor digitorum profundus

17. Branches in the forearm Anterior interosseus nerve Arises between the two heads of pronator teres Descends between and deep to FPL and FDP along with anterior interosseus artery Supplies Flexor policis longus FDP (lateral half i.e. Index and middle finger) Pronator quadratus

18. 2. Muscular braches Pronator teres Flexor carpi radialis Palmaris longus Flexor digitorum superficialis 3. Other branches Articular branch to elbow and wrist joint Palmar cutaneous branch

19. In the wrist 5 cm proximal to the flexor retinaculum it emerges from behind the lateral edge of FDS Lies between the tendons of FDS and FCR Passes laterally from beneath the tendon of Palmaris Longus deep to the retinaculum

20. Branches in the hand Lateral terminal branch Supplies thenar muscles 1 st lumbrical 3 proper palmer digital nerves 2. Medial terminal branch Supplies 2 nd lumbrical 2 common palmer digital nerves

21. Median nerve injury

22. Median nerve can be injured in In the course of arm At Elbow In the forearm At wrist At hand

23. Effects Paralysis of muscle supplied by it Deformity of hand Loss of sensation

24. Classification High : above the origin of Anterior interosseous nerve (proximal to elbow) Low : injury in distal 3 rd of forearm Carpel tunnel syndrome

25. High median nerve injury Injury proximal to elbow Due to forearm fractures or elbow dislocations Stab and gun shot wounds Paralysis of all the muscles supplied by it in forearm and hand

26. Low median nerve injury Injury in distal 3 rd of forearm Cuts in front of wrist and carpel bone dislocations Spare forearm muscle paralysis of muscles of hand, thenar intrinsic muscle paralysis Thumb abduction and opposition weak Sensation lost over radial 3 and half fingers

27. Anesthesia over median nerve distribution in hand Thenar eminence wasted, thumb abduction and oppositions of fingers are weak Sensations lost over three and half of radial fingers

28. Examinations Flexor pollicis longus : patient is asked to flex the terminal phalynx of the thumb while his/her base of thumb is held

29. Flexor digitorium superficialis and profundus : ( oscher’s clasping test) patienr is asked to clasp both the hands where index finger of affected side fails to flex.

30. Flexor carpi radialis : hand deviates to ulnar side when flexed against resistance Muscles of thenar eminance : abductor pollicis brevis ( pen test ): pen is kept level higher than thumb and pts is asked to touch tip of pen

31. Opponens pollicis : patient is asked to touch tip of other finger with tip of thumb

32. Pointing index sign

33. Wasting of thenar eminance

34. Typical area of sensory loss in median nerve palsy

35. Ape thumb deformity

36. Ulnar nerve Composed of fibers from C8 and T1 coming from medial cord of brachial plexus Above the axilla : It courses with the axillary artery and vein and lies deep to pectoralis minor In the axilla , it crosses medial to brachial artery and lies deep to the pectoralis major

37. In the arm At the level of distal attachment of coracobrachialis to the humerus (about 10 cm proximal to the medial epicondyle ), ulnar nerve pierces the medial intermuscular septum to enter the posterior compartment of the arm. Here it lies on the anterior border of the medial head of the triceps Then it passes through the ligament of Struthers and then behind the medial epicondyle through cubital tunnel

38. In the forearm As the nerve exits the cubital tunnel, it courses between the two heads of flexor carpi ulnaris and enters the anterior compartment of the forearm. Shortly after exiting the cubital tunnel, ulnar nerve gives off motor branches to the flexor carpi ulnaris It then lies on the anterior surface of the flexor digitorum profundus At about 5 cm distal to the medial epicondyle , ulnar nerve gives off branches to the ulnar aspect of FDP (providing innervation to long flexors of ring and small fingers) In the middle of the forearm, at about 12 cm distal to the medial epicondyle , ulnar nerve becomes superficial and meets with the ulnar artery as it travels towards the wrist

39. In the wrist Ulnar nerve and artery lie in a canal formed by the pisiform bone medially and the hook of hamate laterally ( guyon’s canal) In this region the nerve divides into The superficial sensory branch– distal palm, 5 th and half of 4 th digit The deep motor branch– hypothenar muscles, adductor pollicis,3 rd and 4 th lumbricals , palmar digital branches to medial one and half fingers

40. Ulnar nerve injury At the level of elbow Motor loss FCU and medial half of FDP paralyzed Profundus tendon to the ring and little fingers will be functionless Terminal phalanges to these fingers fail to flex properly Flexion of wrist will result in abduction due to paralysis of FCU Small muscles of hand will be paralyzed except the muscles of thenar eminence and first two lumbricals Adductor pollicis longus is paralyzed-- adduction of thumb not possible

41. Metacarpophalyngeal joints become hyperextended due to paralysis of lumbrical and interosseus muscles IP joints are flexed (claw hand) Dorsum of hand shows hollowing due to wasting of the dorsal interosseus muscles

42. Sensory loss Loss of skin sensation over anterior and posterior surfaces of medial 3 rd of the hand and medial one and half fingers

43. At the level of wrist Motor loss Small muscles of the hand paralyzed Claw hand more obvious (as FDP not paralyzed) Marked flexion of terminal phalanges occur

44. Sensory loss Sensory loss over the palmer surface of medial 3 rd of the hand and medial one and half finger

45. Froment’s sign Weakness of adductor pollicis : pts asked to grip sheet of paper forcefully between thumb and index finger while examiner try to pull it away, powerful flexion of thumb interphalyngeal joint of affected side signal weakness in adductor pollicis . FPL flexes thumb

46. Card test and Egawa test Inability to hold a card or paper between the fingers due to loss of adduction by the palmer interossei Egawa test With the palm placed flat on the table, the patient is asked to move the middle finger sideways This is a test for the dorsal interossei of middle finger

47. Guyons tunnel syndrome Entrapment of ulnar nerve in pisohammate tunnel( guyon’s canal) Seen in long distance cyclist, lean with pisiform pressing on handlebars

48. Cubital tunnel syndrome(ulnar neuronitis ) Compression or entrapment of nerve in medial epicondylar tunnel( cubital tunnel) Esp in severe valgus deformity of elbow or prolong pressure of elbow on anesthetised patient

49. Autonomous sensory zones These are the regions where single nerve supply distinct and non-overlapping areas of skin Radial nerve: 1st dorsal web space of hand ( Anatomical snuff box ) Median nerve: Distal phalanx (tip) of index finger (2nd finger) Other: Tip of thumb Ulnar nerve: Distal phalanx (tip) of little finger (5th finger)

50. Peripheral nerve injury

51. Classifications Seddon’s classification s: Neurapraxia : reversible physiological nerve conduction block Spontaneous recovery after few days 2. Axonotmesis : loss of conduction but the nerve is in continuity and nerve tubes are intact Recovery may occur but may take several months 3. Neurotmesis : Severe damage to the nerve May occur without actually dividing the nerve Spontaneous recovery unlikely

52. Sunderland classifications : 1 st degree : Transient ischemia and neuroprexia , Reversible 2 nd degree : Seddon’s axonotmesis , regeneration can lead to complete or near complete recovery without intervention. 3 rd degree : worse, endoneurium disrupted but perineural sheath intact, fibrosis limit the recovery

53. 4 th degree : only epineurium is intact, nerve trunk still in continuity but internal damage is severe , recovery unlikely 5 th degree : nerve divided and will have to be repaired

54. Diagnosis Clinical examination Tinel sign– gentle percussion by finger or hammer over the course of injured nerve produces tingling sensation in the distribution of the injured nerve A positive sign is presumptive evidence that regenerating axonal sprouts that have not obtained complete myelinization are progressing along the endoneural tube

55. Imaging High resolution USG MRI Electo -diagnostic studies Nerve conduction velocity Electromyography

56. Treatment of nerve injuries .General considerations Maintain ABC Evalutate nerve injury Open wound should be cleansed and debrided Immediate primary repair of nerve done if Wound is clean and sharply incised Patient is stable Adequate personnel and equipments Delayed primary repair– 7-18 days >18 mths —loss of motor end plates and muscle fibrosis Release of compression

57. When closed fractures are complicated by peripheral nerve injuries, reinnervation awaited and early surgical exploration avoided. If nerve deficit follows manipulation or casting of a closed fracture, early exploration of nerve done.

58. Techniques Neurolysis External neurolysis – nerve is freed from enveloping scar Internal neurolysis – nerve sheath dissected longitudinally to relieve the pressure from the fibrous tissue within the nerve Epineural neurorrhaphy Perineural (fascicular ) neurorraphy individual fasciculi sutured within the nerve trunk Suture used– 8-0 or 9-0 monofilament nylon for epineural suturing and 9-0 or 10-0 for perineural suturing

59. Closing nerve gaps Mobilization of nerve Positioning of joint—to relax the nerve Transposition Bone resection Nerve grafts

60. Interfascicular nerve graft If nerve gap is more than 10 cm Donor nerves Sural Saphenous Lateral cutaneous nerve of thigh Lateral and medial cutaneous nerve of the forearm Posterior cutaneous nerve of the forearm Superficial nerve of the radial nerve Dorsal branch of the ulnar Intercostal nerves

61. Post- operative care Upper limb immobilised in plaster slab (minimum of 4 wks) Wound dressed after 7-10 days

62. Prognosis Age Size of gap Type of injury Level of injury Delay in repair

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