median nerve injury

1. Median Nerve
- Dr. Naresh R Bone
DNB Orthopedic Resident,
KIMS Hospital, Secunderabad

2. Anatomy
• Origin : The median nerve is
derived from both the lateral
and medial cords of the
brachial plexus.
• Root Value: C5,6,7,8,T1
• Also called labourer’s nerve.

3. Course :
• Cubital fossa –Median nerve lying medial to brachial artery & behind
the bicipital aponeurosis.
• It has no branches in Arm
• Enters the forearm by passing between two heads of pronator teres.

4. o In proximal forearm passes beneath
the fibrous arch of flexor digitorum
sup.(FDS) & runs deep to this muscle
o And runs on surface of flexor
digitorum profundus (FDP).
o About 5cm above the flexor
retinaculum ,it becomes superficial
& lies between tendon of flexor
carpi radialis FCR (laterally) & flexor
digitorum sup. FDS(Medially).
o Enters the palm by passing deep
flexor retinaculum

5. Branches:
• Muscular branches : a. Flexor carpi radialis (FCR)
b. Palmaris longus
c. flexor digitorum sup.(FDS)
• Anterior interosseus nerve : Flexor pollicis longus
Flexor digitorum profundus
Pronator Quadratus
• In hand : Abductor pollicis brevis
Flexor pollicis brevis Thenar Eminence
Opponens pollicis
Lumbricals (1st & 2nd)
Palmar skin over the lateral 3 ½ digits
with their nail beds

6. Cont…
• Also supplies distal radioulnar & wrist joints
• Palmar cutaneous branch – Skin over the thenar eminence

7. Clinical findings:
1. Injury at the Elbow:
• Motor functions:
• The flexors and pronators in the forearm are paralysed, with the exception of the
flexor carpi ulnaris (FCU) and medial half of flexor digitorum profundus (FDP).
• The forearm constantly supinated, and flexion is weak
• Flexion at the thumb is also prevented, as both the longus and brevis muscles
are paralysed.
• The lateral two lumbrical muscles are paralysed, and the patient will not be able
to flex at the MCP joints or extend at IP joints of the index and middle fingers.

8. • Sensory functions: Lack of sensation over the areas that the median
nerve innervates.
• Characteristic signs: The thenar eminence is wasted, due to atrophy
of the thenar muscles.
• If patient tries to make a fist, only the little and ring fingers can flex
completely. This results in a characteristic shape of the hand, known
as hand of benediction

9. Hand of Benediction

10. 2. Injury at the Wrist:
• How it commonly occurs: Lacerations just proximal to the flexor
reticaculum.
• Motor functions: Thenar muscles paralysed, as are the lateral two
lumbricals.
• This affects opposition of the thumb and flexion of the index and
middle fingers.
• Sensory functions: Same as an injury at the elbow.

11. Motor Functions
Main median nerve
• Pronator teres (C6–C7) - forearm pronator
• Flexor carpi radialis (C6–C7) - radial flexor of the hand
• Palmaris longus (C7–T1) - flexor of the wrist.
• Flexor digitorum superficialis (C7–T1) - a flexor of the middle
phalanges of the 2nd , 3rd , 4th and 5th fingers

12. Motor function
anterior interosseus nerve
• Flexor pollicis longus (C7–C8) - flexor of the terminal phalanx
of the thumb
• Flexor digitorum profundus (C7–C8) flexor of the terminal
phalanges of the 2nd and 3rd fingers
• Pronator quadratus (C7–C8) a forearm pronator

13. Small muscles of hand
•Abductor pollicis brevis (C8-T1) - abductor of the metacarpal of the
thumb
• Opponens pollicis (C8–T1) - muscle that brings the metacarpal of the
thumb into opposition
• Superficial head of the flexor pollicis brevis (C8–T1) - a flexor of the
proximal phalanx of the thumb
• Lumbricals I and II (C8–T1) - flexors of the MCP proximal IP and
extensors of the two distal phalanges of the second and third fingers

14. Median nerve clinical assessment
1. Pronator teres (C6, C7) assessment: The patient’s forearm is
extended and fully pronated. The patient is then instructed to resist
supination of the forearm by the examiner

15. 2. Flexor carpi radialis (C6, C7) assessment
• The hand deviates to ulnar side when it is flexed against resistance.

16. 3. Flexor digitorum superficialis (C8, T1) assessment
• Examiner holds the all fingers except one being tested in extension.
This isolate the FDS , ask the patient to flex PIP jt against resistance.

17. 4. Flexor digitorum profundus (C8, T1)
assessment
• Examiners extend all the jnts of pt except DIP & ask the pt to flex the
DIP

18. Oschners clasping test
• When the pt asked to clasp the hands the index finger of affected side
fail to flex & remains as a pointing index

19. Okay” or “circle” sign with anterior interosseous nerve
weakness
• Ask the patient to make an okay sign by touching the tips of the
thumb and index finger together.
• With weakness in these muscles, the distal phalanges cannot flex, and
instead of the fingertips touching, the volar surfaces of each distal
phalanx make contact.

20. Abductor pollicis brevis (C8, T1) assessment
Abduction of thumb , pen is kept at a level higher than thumb & pt
asked to touch the tip of pen.

21. Clinical Conditions:
• Carpal tunnel syndrome
• AIN Neuropathy
• Pronator Syndrome

22. Carpal tunnel syndrome
• MC upper extremity compression neuropathy & result
from median nerve compression with in carpal tunnel

23. Carpal tunnel

24. Factors involved in pathogenesis of CTS
•Increase in content of canal ( in cross sectional area
of canal) : a) Malaligned colles fracture
b) Oedema from infection or trauma
c) Tumors or space occupying lesion
d) Post traumatic arthritis (osteophytes)
•Neuropathic condition :
a) D.M.
b) Alcoholism
•Inflammatory Condition : R.A. , Gout, non-specific
tenosynovitis

25. Cont…
• Alteration of fluid balance : a) Pregnancy
b) Hypothyroidism
c) Obesity
d) renal failure

26. Symptoms :
• Age – 30 to 60 yrs
• Tingling & numbness in typical median nerve distribution
• Pain – deep aching , throbbing diffusely in hand & radiate upto
forearm
• Patient wakes at night with burning or aching pain and relieved by
exercise

27. Diagnosis
• History
• Clinical examination: - Thenar wasting
- Phalen’s sign
- Tinel’s sign
- Carpal compression test (Durkan test)
• Electro Diagnostic Studies
• Nerve conduction studies

30. Tinel’s sign
• When the examiner tap over the carpal tunnel , pt will fill paresthesia
or pain distally.

31. Durkan test
• Compression is applied to median nerve for 30 sec with thumb.

32. Management
• Splinting – prevents wrist flexion
• Corticosteroid / anaesthetic injection
• Surgical decompression: Division of the transverse carpal ligament
- Open
- Endoscopic

33. Splint

34. Open carpal tunnel release

35. Complications
• Injury to palmar cutaneous/recurrent motor branch of the median
nerve
• Hematoma/Arterial injury

36. Anterior interosseus nerve syndrome
• Compression of the AIN nerve
• also known as Kiloh-Nevin's syndrome
• Is a forearm compressive neuropathy that results in motor
deficits of the AIN nerve without sensory changes

37. Causes
• Entrapment of AIN between
a) tendinous edge of deep head of
pronator teres
b) fibrous arch of the FDS
c) accessory head of FPL (Gantzer's
muscle)

38. Accessory head of FPL (Gantzer's muscle)

39. Clinical presentation
• motor deficits without sensory loss
• On examination :
a) Inspection : severe disease may show forearm atrophy
b) Neurovascular : weakness of grip and pinch, specifically
thumb, index and middle finger flexion
-Normal median nerve sensory exam

40. Treatment :
• Nonoperative
observation, rest and physical therapy
• Operative
surgical decompression of AIN
Indications - clear space occupying mass
- if nonoperative treatment fails after 12 months

41. Pronator Syndrome
• A compressive neuropathy of the median nerve at the level
of the elbow
• more common in women
• common in 5th decade
• has been associated with well-developed forearm muscles (e.g.
weight lifters)

42. Pathoanatomy
• Sites of entrapment include :
a) supracondylar process
b) ligament of Struthers

43. • bicipital aponeurosis
• between ulnar and humeral heads of
pronator teres

44. Clinical presentation :
• Paresthesias in thumb, index, middle finger and radial half of
ring finger as seen in carpal tunnel syndrome.
• worse with repetitive pronosupination
• Differentiating from carpal tunnel syndrome –
- aching pain over proximal volar forearm
- lack of night symptoms

45. Management
• Radiograph : X-ray – Elbow
• Treatment :
a) Nonoperative : Rest, splinting, and NSAIDS for 3-6 months
b) Operative : Surgical decompression of median nerve
- only when nonoperative management fails for 3-6 months

46. Thank You