Median nerve palsy final

1.Anatomy
a.Course
b.Motor distribution
c.Sensory distribution
2.Common sites affected
3.Level of median nerve injury
4.Clinical feature with various test performed
5.Various syndromes related to median nerve
6.Treatment
7.Summary

1. MEDIAN NERVE PALSY Presented by Intern Dr. Animesh Kunwar SBH

2. Outline Anatomy Course Motor distribution Sensory distribution C ommon sites affected Level of median nerve injury Clinical feature with various test performed Various syndromes related to median nerve Treatment Summary

3. C5 C6 C7 C8 T1 SUPERIOR MIDDLE INFERIOR LATERAL POSTERIOR MEDIAL Median nerve (C5, 6, 7, 8, T1) This nerve is formed by the joining of branches from the lateral and medial cords of brachial plexus. ROOTS TRUNKS CORDS TERMINAL BRANCHES ANATOMY: COURSE

4. In the arm, the median nerve descends adjacent to the brachial artery. brachial artery Median nerve The nerve enters the forearm between the two heads of the pronator teres Course in the forearm

5. It then passes deep to the tendinous bridge of the origin of the flexor digitorum superficialis , proximal third of the forearm. In the mid-forearm it descends between the flexor digitorum superficialis and flexor digitorum profundus About 5 cm above the wrist, it comes to lie on the lateral side of the flexor digitorum superficialis . It becomes superficial just above the wrist, where it lies between the tendons of the flexor digitorum superficialis and flexor carpi radialis .

6. Course in the hand: The nerve passes deep to the flexor retinaculum and enters the palm. Here a short and stout muscular branch from it supplies the muscles of the thenar eminence abductor pollicis brevis , opponens pollicis and flexor pollicis brevis

7. The median nerve finally divides into 4 to 5 palmar digital branches supplying the area of skin Also , motor branches are given to the first and second lumbrical muscles at this level.

8. Motor distribution Hand : the thenar muscles and the lateral two lumbricals . Forearm (through its anterior interosseous branch): flexor pollicis longus , half of flexor digitorum profundus , pronator quadratus . ( C) Near the elbow: flexor digitorum superficialis , flexor carpi radialis , palmaris longus and pronator teres

9. Sensory distribution

10. (A) In the carpal tunnel (e.g. carpal tunnel syndrome, and some fractures and dislocations about the wrist ). ( B) At the wrist (e.g. from lacerations ). ( C) At the elbow ( e.g. after elbow dislocations in children). (D)In the forearm (anterior interosseous nerve ) from forearm bone fractures, or by a tight tissue band at the origin of the superficialis . (E) Just distal to the elbow, in the pronator teres nerve entrapment syndrome Median nerve: common sites affected

11. L evel of median nerve injury High median nerve palsy (injury proximal to the elbow): Low median nerve palsy (injury in the distal-third of the forearm): This will cause paralysis of all the muscles supplied by the median nerve in the forearm and hand. There will be sparing of the forearm muscles, but the muscles of the hand will be paralysed . In addition to lower nerve lesion, the long flexors to the thumb, index and middle fingers, the radial wrist flexors and the forearm pronator muscles are all paralysed The patient is unable to abduct the thumb, and sensation is lost over the radial three and a half digits.

12. High median nerve palsy Low median nerve palsy Typically the hand is held with the ulnar fingers flexed and the index straight (the ‘pointing sign’). Also, because the thumb and index flexors are deficient, there is a characteristic pinch defect: instead of pinching with the thumb and index fingertips flexed, the patient pinches with the distal joints in full extension In long standing cases the thenar eminence is wasted and trophic changes may be seen

13. Clinical features Lack of ability to abduct and oppose the thumb due to paralysis of the thenar muscles. This is called "ape-hand deformity ". Sensory loss in the thumb, index finger, long finger, and the radial aspect of the ring finger Weakness in forearm pronation and wrist and finger flexion

14. TEST

15. . Flexur policis longus Loss of power here may also occur in median nerve lesions proximal to the anterior interosseous branch

16. Flexur digitorum superficialis and Lateral half of flexor digitorum profundus If the patient is asked to clasp his hand, the index finger will remain straight, the so-called 'pointing index'. This occurs because both the finger flexors, superficialis as well as the profundus of the index finger are paralysed ;

17. Flexur carpi radialis In paralysed patient wrist deviates to the ulnar side while palmar flexion occurs. In addition , one cannot feel the tendon of the flexor carpi radialis getting taut.

18. Muscle of thenar eminence Opponens policis The function of this muscle is to appose the tip of the thumb to other fingers

19. Testing abductor pollicis brevis

20. Look for impairment of sensation to pinprick in the area of distribution of the nerve. Testing for sensation

21. Median nerve compression Carpel tunnel syndrome Pronator syndrome Anterior interosseous syndrome

22. Carpal tunnel syndrome caused by compression of the median nerve as it passes under the carpal tunnel . Nerve conduction velocity tests through the hand are used to diagnose CTS . Physical diagnostic tests include the  Phalen maneuver or Phalen test and  Tinel's sign To relieve symptoms, patients may describe a motion similar to "shaking a thermometer", another indication of CTS .

23. Tinel test A) flexor carpi radialis longus B ) palmaris longus

24. Phalen test

25. Pronator teres syndrome   is compression of the median nerve between the two heads of the pronator teres muscle  The Pronator teres test—the patient reports pain when attempting to pronate the forearm against resistance while extending the elbow simultaneously .  The key to discerning this syndrome from carpal tunnel syndrome is the absence of pain while sleeping .

26. Extend the patient’s elbow and feel for contraction in the muscle as he attempts to pronate the arm against resistance . Loss indicates a lesion at or above the elbow. Accompanying pain and tenderness over pronator teres is found in the pronator teres entrapment syndrome Testing pronator teres .

27. Anterior interosseous syndrome AIN syndrome is purely neuropathic . AINS is considered as an extremely rare 1 % of neuropathies in the upper limb. Patients have impaired distal interphalangeal joint, because of which they are unable to pinch anything or make and "OK" sign with their index finger and thumb. The syndrome can either happen from pinched nerve, or even dislocation of the elbow

28. Treatment C onservative treatment 1 st step -rest and modify daily activities that aggravate the symptoms. CTS- anti-inflammatory drugs, Physical or Occupational therapy , splints for the elbow and wrists, and corticosteroid   injections   In pronator teres syndrome - immobilization of the elbow and mobility exercise within a pain-free range are initially prescribed.

29. Surgical Treatment I f the patient is not relieved of symptoms after a usual 2 to 3 month refractory period, then decompression surgery may be required. Surgery involves excising the tissue or removing parts of the bone compressing the nerve.

30. Treatment If the nerve is divided, suture or nerve grafting should always be attempted. Postoperatively the wrist is splinted in flexion to avoid tension; when movements are commenced , wrist extension should be prevented. If there has been no recovery, the disability is severe because of sensory loss and deficient opposition.

31. Rehabilitation In high median nerve palsy patients, recovery time varies from as early as four months to 2.5 years. Initially , patients are immobilized in a neutral position of the forearm and elbow flexed at 90° in order to prevent further injury. Additionally , gentle exercises and soft tissue massage are applied. The next goal is strengthening and flexibility, usually involving wrist extension and flexion; however, it is important not to overuse the muscles in order to prevent re-injury.

32. Summary Median nerve (C5, 6, 7, 8, T1 ), by joining lateral and medial cords Motor branches in forearm are all the flexor muscle of the forearm except flexor carpi ulnaris and medial half of flexor digitorum profundus ; and in hand, thenar muscles and first two lumbricals Sensory functions-   Gives rise to the palmar cutaneous branch, which innervates the lateral part of the palm, and the digital cutaneous branch, which innervates the lateral three and a half fingers on the anterior (palmar) surface of the hand.

33. Level of median nerve injury High median nerve palsy (injury proximal to the elbow) and Low median nerve palsy (injury in the distal-third of the forearm Ape hand deformity is usually seen Carpel tunnel syndrome, Pronator syndrome, Anterior interosseous syndrome Treatment includes both conservative and surgical treatment with rehabilitation

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