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ENMG of Brachial Plexus F. Wang To localize To exclude To assess severity.

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Presentation on theme: "ENMG of Brachial Plexus F. Wang To localize To exclude To assess severity."— Presentation transcript:

1 ENMG of Brachial Plexus F. Wang To localize To exclude To assess severity

2 Easy diagnosis ? 1.Post- ganglionic multitroncular mononeuropathy 2.Sensory and motor neuropathy or pure motor neuropathy (Parsonage & Turner, MMN) 3.Axonal or demyelinating neuropathy (dysimmune neuropathies) 4.SNAP/CMAP : absent or reduced in amplitude MCV & distal latency : usually normal Erb’s point stimulation : sometimes prolonged latency or conduction block (MMN, plexopathy due to radiations) F wave : prolonged if demyelination in C7-D1 territory EMG : acute, subacute or chronic neurogenic traces

3 Tricky diagnosis ? The main difficulty is related to : -Anatomy

4 Three questions 1. Pre- or post-ganglionic lesion ? 2. Spinal nerve or plexus ? 3. Trunk or cord ? or SUPER root or SUPER nerve ? And then you realized that things are more complicated…

5 Pre- or post-ganglionic lesion ? 1.Paravertebral muscles 2.SNAPs There is not sensory axonal degeneration in the case of pre-ganglionic lesion, even if this nervous lesion is complete. 1 or 2 cm out of the median line 1 or 2 cm out of the median line At the intervertebral space At the intervertebral space

6 TPS TPM TPI TSAE TSAI SNAPs Radial nerve – Posterior cord – Upper/Middle trunks – C6(C7) Thumb – Radial nerve – posterior cord – upper trunk – C6 LABC nerve – Lateral cord – Upper trunk – C6 MABC nerve – Medial cord – Lower trunk – C8 Thumb – Median nerve – Lateral cord – Upper trunk – C6 3rd finger – Median nerve – Lateral cord – Middle trunk – C7 5th finger – Ulnar nerve – Medial cord – Lower trunk – C8 Right/Left difference in amplitude : ≥ 50% is abnormal Pre- or post-ganglionic lesion ?

7 Spinal nerve or plexus ? Dorsal scapular nerve Long thoracic nerve Nerve to subclavius muscle Ventral rami

8 1. Long thoracic nerve (C5,C6,C7) : serratus anterior 2. Dorsal scapular nerve (C5) : rhomboid minor and major and levator scapulae 3.Nerve to subclavius muscle (C5,C6) Spinal nerve or plexus ?

9 Trunks : supraclavicular and pass between scalenus medius and scalenus anterior Cords : infraclavicular Divisions (between trunks & cords) : retroclavicular Trunks or Cords ? Anatomical classification of lesions

10 SUPER root or SUPER nerve ? Simplified view Upper trunk Middle trunk Lower trunk C5 C6 C7 C8 T1 Lateral cord Posterior cord Medial cord Musculocutaneous Median (C6-C7) Radial Axillary Ulnar Median (C8-T1) Medial antebrachial cutaneous TPS TPI TPM TSAE TSP TSAI

11 Upper trunk C5 + C6 Suprascapular nerve C5 C6

12 Upper trunk C5 + C6 1. C5 & C6 post-ganglionic lesion 2. With suprascapular nerve lesion (most often) 3.Without involvement of long thoracic & dorsal scapular nerves

13 Upper trunk C5 + C6 1. C5 mot.: deltoid ( CMAP ) 2. C6 mot.: biceps ( CMAP,T ), ext. carpi rad. brevis, pronator teres 3. C5/C6 SNAPs: radial, median/R1 lateral antebrachial cutaneous 4.Suprascapular nerve (C5,C6) 5. Tendon reflex: biceps & brachioradialis

14 1.Moto crash 2.Obstetrical trauma 3.Parsonage & Turner 4.Infiltrative plexopathy 5.Rucksack paralysis 6.“Burner syndrome (sport trauma) 7.Post-anesthesia 8.Infection : Lyme 9.Vasculitis 10.Heroin Upper trunk lesions C5 + C6

15 Upper trunk lesions C5 + C6 Schwannome

16 Lateral cord musculocutaneous + median (C6C7) nerves Musculocutaneous nerve Median nerve Lateral pectoral nerve

17 1. Musculocutaneous mot.: biceps ( CMAP ), brachialis 2. Median (C6C7) mot: pronator teres, flexor carpi radialis ( H ) 3.Median R1-R4/lateral antebrachial cutaneous SNAPs 4. Lateral pectoral nerve : pectoralis major 5. Tendon reflex: biceps Lateral cord musculocutaneous + median (C6C7) nerves

18 Middle trunk C7 C7

19 1.C7 post-ganglionic lesion Middle trunk C7

20 1. C7 mot.: triceps ( T ), flexor carpi radialis ( H ), extensor digitorum, anconeus ( CMAP/F ) 2. C7 SNAPs: median/R2+R3, radial, PABC 3. Tendon reflex: triceps Middle trunk C7

21 Posterior cord radial + axillary nerves Axillary nerve Radial nerve Axillary Radial Thoracodorsal nerve Lower subscapular nerve

22 1. Radial mot: triceps ( T ), extensor digitorum, extensor indicis, ECU( CMAP), anconeus ( CMAP/F ) 2. Axillary mot: deltoid ( CMAP ), teres minor 3. Thoracodorsal mot : latissimus dorsi 4. Lower subscapular mot : teres major, (subscapularis) 5.Radial SNAP 6.Triceps and brachoradialis reflexes are abnormal Posterior cord radial + axillary nerves

23 1.Humeral head fracture/luxation 2.Supra-clavicular wounds Posterior cord lesions radial + axillary nerves

24 Lower trunk C8 + D1 Medial brachial cutaneous nerve Medial antebrachial cutaneous nerve Medial pectoral nerve C8 D1

25 1. C8 & D1 post-ganglionic lesion 2.With medial brachial & antebrachial cutaneous With medial pectoral Reminder : APB & medial brachial cutaneous D1 > C8 ulnar nerve C8 > D1 Lower trunk C8 + D1

26 1. C8/D1 mot.: APB ( CMAP/F ), ADM ( CMAP/F ) Interosseous I, extensor indicis, pectoralis minor & major (sternocostal portion) 2. C8/D1 SNAPs: ulnar/R4+R5, medial brachial & antebrachial cutaneous 3.No reflex abnormalities Lower trunk C8 + D1

27 Lower trunk C8 + D1 Pectoralis majorPectoralis minor Clavicula 2 Nipple 3 anterior axillary line 4 Pectoralis major (clavicular part, C5C6) 5 Pectoralis major (sternocostal part, C7C8) 6 Pectoralis minor (C7C8) Right TOS

28 Medial brachial cutaneous nerve Medial antebrachial cutaneous nerve Medial pectoral nerve Medial cord Ulnar + median (C8D1) nerves Median nerve Ulnar nerve

29 1. Ulnar & median (C8D1) 2.With medial brachial & antebrachial cutaneous (sometimes) With medial pectoralis nerve (sometimes) 3.Without C8 radial muscles Medial cord Ulnar + median (C8D1) nerves

30 1. C8/D1 mot.: APB ( CMAP/F ), ADM ( CMAP/F ) Interosseous I, pectoralis minor 2. C8/D1 SNAPs: ulnar/R4+R5, medial brachial & antebrachial cutaneous 3.No reflex abnormalities Medial cord Ulnar + median (C8D1) nerves

31 1.TOS 2.Pancoast Tobias 3.Metastatic 4.Neurofibroma Schwannoma Meningioma 5.Trauma in abd. 6.Post-sternotomy 7.Radiotherapy 8.Dys. neuropathy Lower trunk or medial cord lesions

32 Dys. neuropathy

33 Lower trunk or medial cord lesions Non small-cell lung tumor

34 Upper TMiddle TLower TLateral CPosterior C Medial C 1. Deltoid (C5C6) : CMAP, EMG ___ 2. Infraspinatus (C5C6) : CMAP (needle), EMG ___ 3. Biceps (C5C6) : CMAP, T, EMG +____ 4. Pronator teres (C6C7) : EMG +___ 5. Flexor carpi radialis (C6C7) : H, EMG _+__ 6. Triceps (C6C7C8) : T, EMG _+_ 7. Extensor indicis (C7C8D1) : EMG __ 8. Abductor pollicis brevis (C8D1) : CMAP, F, EMG ____ 9. Abductor digiti minimi (C8D1) : CMAP, F, EMG ____ 10. Pectoralis major (C5C6C7C8) : EMG +_ 11. Pectoralis minor (C7C8) : EMG _+__+ 12. Teres major (C5C6C7) : EMG __+_ 1. Radial (C6C7) : SNAP ___ 2. R1/median (C6) : SNAP +__+__ 3. R3/median (C7) : SNAP _+_+__ 4. Medial antebrachial cut.(D1) : SNAP ____ 5. R5/ulnar (C8) : SNAP __+__+ 6. Lateral antebrachial cut. (C6) : SNAP +____

35 Simplified view LesionMotorSensoryTendon Reflex LOWER TRUNK C8 + D1 APB-ADM Extensor indicis MABC R5 No reflex abnormalities MEDIAL CORD Ulnar + Median C8D1 APB-ADMMABC R5 No reflex abnormalities UPPER TRUNK C5 + C6 Deltoid Infraspinatus Radial R1/LABC Biceps Brachioradialis POSTERIOR CORD Radial + Axillary Deltoid Extensor indicis Radial onlyBrachioradialis Triceps MIDDLE TRUNK C7 Triceps FCR Radial R3 Triceps only LATERAL CORD Musculocutaneous + Median C6C7 Biceps Pronator teres Median (R1- R4) LABC Biceps only

36 The simplest view 1. Inferior plexus : hand intrinsic muscles APB, ADM, MABC, R5 with EI => LT without EI => MC 2. Superior plexus : elbow and wrist flexion BB, FCR, PT with D and radial SNAP => UT without D, with median SNAP => LC 3. Middle/posterior plexus : elbow and wrist extension TB, radial SNAP without EI => MT with D => PC

37 Thanks E Fournier JF Camdessanché AL Derelle et al A Echaniz-Laguna HW van Es et al MI Vargas et al


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