Clinical correlation of (peripheral) nerve injuries of limbs

1. Clinical correlation of (peripheral) nerve injuries of limbs AjithSominanda Department of Anatomy Faculty of Medicine University of Peradeniya

2. Lecture outline • Introduction • Classification • Clinical features of nerve injuries • Clinically useful guide to test dermatomes & myotomes & reflexes • Upper limb peripheral nerve injuries • Injuries to brachial plexus • Injuries to individual nerves of the brachial plexus • Long thoracic, Axillary, Median, Ulnar & Radial • Lower limb nerve injuries • A revision to Lower limb muscle compartments and their nerves • Injuries and clinical manifestation • Nerve root injuries (radiculopathy)

3. Classification of nerve injuries • Neuropraxia • Temporary loss of function caused by minor trauma or pressure • Recovery is fast • Axonotmesis • Loss of function due to damage to axons but nerve sheaths are intact • Recovery occurs slowly • Neurotmesis • Loss of function due to division of nerve • No recovery occurs unless nerve is repaired

4. Clinical features of nerve injuries • Reduced or absent sensation • Weakness or paralysis of muscle or group of muscles • Autonomic dysfunction e.g. absence of sweating In neuropraxia, nerve dysfunction is partial whereas in neurotmesis & axonetmesis it is almost complete dysfunction.

5. Clinically useful guide to test myotomes Upper limb • Shoulder abduction C5 • Elbow flexion C6 • Elbow extension C7 • Finger flexion C8 • Small muscles of Hand T1 Lower limb • Hip flexion L2-L3 • Knee Extension L3-L4 • Ankle inversion L4-L5 • Plantar flexion S1-S2 • Hip extension/Knee flexion/ankle evertion / dorsiflexion L5-S1

6. Clinically useful guide to test Dermatomes (test areas of least overlap) Upper limb • Top of shoulder C4 • Thumb C6 • Middle finger C7 • Little finger C8 • Axilla T3 Lower Limb Upper thigh L1 Middle thigh L2 Lower thigh L3 (knee antero-medial) Medial malleolus L4 Middle 3 toes L5 Lateral malleolus S1 Back of leg S2 Gluteal fold S3

7. Tendon Reflexes • Biceps jerk evaluates • Biceps muscle • Musculocutaneous nerve • C5,6 roots (segments) • Knee Jerk evaluates • Quadriceps muscle • Femoral Nerve • Primarily L4 nerve root (also L2, L3) • Ankle Jerk evaluates • Gastrocnemius muscle • Tibial Nerve • Primarily the S1 nerve root (also S2)

8. Revise the Dematome map

9. Upper limb nerve injuries

10. Brachial plexus injuries Brachial plexus is a network of nerves formed at the root of the neck and in the axilla

11. Overview of Brachial Plexus

12. Major nerves (branches) of the brachial plexus that supply the upper limb • Musculo cutaneous nerve • Axillary nerve • Median nerve • Ulnar nerve • Radial nerve • Cutaneous nerves

14. Brachial plexus injuries

15. muscles which are likely to be affected in traction injuries to brachial plexus Reference: Baley & love text book of surgery

16. Specific Brachial plexus injuries • Upper brachial plexus injury; Erb's palsy • the upper nerve root/s (C5,6,(7)) • Shoulder adduction, medial rotation of arm & elbow extension(waiter’s tip hand) • Loss of sensation over lateral border of upper limb • Lower brachial plexus injury, Klumpke's palsy • the lower nerve roots (C8,T1) • small muscles of hand are paralysed(claw hand) • Loss of sensation over medial border of upper limb

17. Injuries to individual nerves of the brachial plexus

18. Injury to long thoracic nerve (C5-7) • Paralysis of serratus anterior muscle • ’winged scapula (a sign)’

19. Injury to axillary nerve (C5,C6) • Paralysis of Deltiod • Sensory loss due to the invovement of superior lateral cutaneous nerve

20. Median nerve (C5-8,T1) • Pronatorteres • FCR • Palmaris longus • FDS • FDP (2,3 digits) • Pronator quadratus • Thenar muscles • Lumbricals (2,3)

22. Median nerve(Elbow or above) • Commonly injured at elbow • Motor paralysis due to loss of: • The pronators • Flexors of wrist & fingers (except FCU, FDP inner half) • Abductor and opponenspollicis • ’Hand of Benediction’ when asked to flex fingers • Sensory loss over thumb, index, middle and half of ring fingers

23. Median nerve(Wrist)

24. Carpal tunnel syndrome

25. Ulnar nerve (C7,C8,T1) • FCU • FDP (4,5 digits) • Hypothenar muscles • Adductor policis • Palmaris brevis • Palmar / Dorsal interossei • Lumbricals (4,5)

27. Ulnar nerve • Often injured with fractures of the medial epicondyle of the elbow • Motor paralysis results in 'claw hand' and hypothenar wasting due to loss of: • Ulnar flexor of the wrist • Flexors of the terminal phalanx of the ring and little finger • Muscles of the hypothenar eminence • Adductor pollicis • Palmar brevis • All the interossei and the medial two lumbricals • Sensory loss over little and half of ring finger

30. Radial nerve (C5-8,T1) • Triceps brachi • Brachioradialis • Anconeus • ECRL • ECRB • Supinator • ECU • EDM • Extensor digitorum • APL • EPB • EPL • Extensor indicis

31. Radial nerve • Often injured in radial groove or in axilla • Motor paralysis results in typical 'wrist drop' due to loss of Wrist and fingers extensors • Supinator and brachioradialis are affected • *** Extension of elbow /triceps is spared in injury at radial groove • Sensory loss in back of forearm and base of thumb • posterior interosseus nerve may be injured at upper end of radius causeing paralysis of long extensors of fingers.

33. Principles of Localization • Nerve opposing bone - Ulnar nerve on medial epicondyle, Supra condylar region and median nerve, radial groove, surgical neck, anatomical snuff box • Closed spaces - carpal tunnel • Adjacent structures - Median nerve adjacent to brachial artery at elbow • Movements at specific joints • Single nerve: Elbow extension Radial nerve • Multiple nerves (Elbow flexion by Musculocutaneous Radial)

34. Case history • 50yrs old man complains of numbness in his medial aspect of the right hand. On examination, finger abduction and adduction were weak with atrophy of interosseus muscles, but normal wrist movements and flexion, extension of thumb

36. Ulnar nerve Elbow Flexor carpiulnaris Flex Dig Prof III/IV Dorsal ulnarcutaneous Wrist Adductor Pollicus Abductor Flex Pollicus Br OpponensDigitiMinimi Flexor Dorsal/palmar Interosseous 3rd/4th lumbricals

37. Lower limb nerve injuries

38. Compartments

40. L4 L1 L2 L5 L3 S1 L4 S2 L5 S3 S4 Lumbosacral plexus S5

41. Main Nerves to the lower limb • Gluteal Nerves • Superior GN • Inferior GN • Femoral Nerve • Obturator nerve • Sciatic nerve • Tibial Nerve • Common Peroneal (fibular) nerve • Superficial Peroneal • Deep Peroneal

42. Video

43. Distribution of Femoral nerve • Nerve of the anterior compartment of thigh • Knee extension • Cutaneous to medial aspect of leg and foot

44. Distribution of obturator nerve • Nerve of the Medial (adductor) compartment of thigh • Hip Adduction • Cutaneous to medial aspect of thigh

45. Sciatic nerve Consists of Tibial and Peroneal (fibular) components

46. Distribution of Sciaticnerve Tibial component Nerve of the posterior compartment of thigh (hamstrings) & Leg (gastrocnemus, soleus, tibialis posterior, FDL, FHL) Knee flexion, Foot plantar flexion, toes plantar flexion Cutaneous sole of foot

47. Peronial (fibular) nerve

48. Distribution of Peroneal (fibular Nerve) • Nerve of the lateral (superficial P) & anterior compartment (Deep P) of the leg • Foot dorsiflexion, toe extension • Cutaneous to lateral leg & dorsum of foot

49. 1st web space sensation is a test of deep fibular nerve

50. Summary : Compartments & the nerves Femoral nerve Obturator nerve Sciatic nerve Deep peroneal Tibial nerve Sup. peroneal nerve