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Clinical correlation of (peripheral) nerve injuries of limbs Ajith Sominanda Department of Anatomy Faculty of Medicine University of Peradeniya 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 • • Lower limb nerve injuries – – • Long thoracic, Axillary, Median, Ulnar & Radial A revision to Lower limb muscle compartments and their nerves Injuries and clinical manifestation Nerve root injuries (radiculopathy) 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 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. Clinically useful guide to test myotomes Upper limb • Shoulder abduction C5 • Elbow flexion C6 • Elbow extension C7 • Finger flexion C8 • Small muscles of Hand Lower limb • Hip flexion • Knee Extension • Ankle inversion • Plantar flexion T1 L2-L3 L3-L4 L4-L5 S1-S2 • Hip extension/Knee flexion/ankle evertion / dorsiflexion L5-S1 Clinically useful guide to test Dermatomes (test areas of least overlap) Upper limb • Top of shoulder • Thumb • Middle finger • Little finger • Axilla C4 C6 C7 C8 T3 Lower Limb Upper thigh Middle thigh Lower thigh Medial malleolus Middle 3 toes Lateral malleolus Back of leg Gluteal fold L1 L2 L3 (knee antero-medial) L4 L5 S1 S2 S3 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) Revise the Dematome map Upper limb nerve injuries Brachial plexus injuries Brachial plexus is a network of nerves formed at the root of the neck and in the axilla Overview of Brachial Plexus Major nerves (branches) of the brachial plexus that supply the upper limb 1. 2. 3. 4. 5. 6. Musculo cutaneous nerve Axillary nerve Median nerve Ulnar nerve Radial nerve Cutaneous nerves Brachial plexus injuries muscles which are likely to be affected in traction injuries to brachial plexus Nerve root Muscles C5 Rhomboids, Deltoid, Teresminor, Biceps, Brachialis, Brachioradialis, supinator C6 Pect.major (clav.head) & minor, subscapularis, coracobrachialis, latissimus dorsi,teres major, serratus anterior, triceps, pronator teres & quadratus Extensors of fingers, ECU, Pect.major (st.costal head) C7 C8 Flexors of wrist & fingers T1 Small muscles of hand Reference: Baley & love text book of surgery 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 Injuries to individual nerves of the brachial plexus Injury to long thoracic nerve (C5-7) • Paralysis of serratus anterior muscle • ’winged scapula (a sign)’ Injury to axillary nerve (C5,C6) •Paralysis of Deltiod •Sensory loss due to the invovement of superior lateral cutaneous nerve Median nerve (C5-8,T1) •Pronator teres •FCR •Palmaris longus •FDS •FDP (2,3 digits) •Pronator quadratus •Thenar muscles •Lumbricals (2,3) 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 opponens pollicis • ’Hand of Benediction’ when asked to flex fingers • Sensory loss over thumb, index, middle and half of ring fingers Median nerve (Wrist) Carpal tunnel syndrome Ulnar nerve (C7,C8,T1) •FCU •FDP (4,5 digits) •Hypothenar muscles •Adductor policis •Palmaris brevis •Palmar / Dorsal interossei •Lumbricals (4,5) 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 Radial nerve (C5-8,T1) •Triceps brachi •Brachioradialis •Anconeus •ECRL •ECRB •Supinator •ECU •EDM •Extensor digitorum •APL •EPB •EPL •Extensor indicis 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. 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) 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 Ulnar nerve Elbow Flexor carpi ulnaris Flex Dig Prof III/IV Dorsal ulnar cutaneous Wrist Adductor Pollicus Flex Pollicus Br Abductor Opponens Flexor Dorsal/palmar Interosseous 3rd/4th lumbricals Digiti Minimi Lower limb nerve injuries Compartments L1 L2 L4 L5 L3 L4 L5 S1 S2 S3 S4 Lumbosacral plexus S5 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 • Video Distribution of Femoral nerve • Nerve of the anterior compartment of thigh • Knee extension • Cutaneous to medial aspect of leg and foot Distribution of obturator nerve • Nerve of the Medial (adductor) compartment of thigh • Hip Adduction • Cutaneous to medial aspect of thigh Sciatic nerve Consists of Tibial and Peroneal (fibular) components Distribution of Sciatic nerve 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 Peronial (fibular) nerve 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 1st web space sensation is a test of deep fibular nerve Summary : Compartments & the nerves Femoral nerve Obturator nerve Sciatic nerve Deep peroneal Sup. peroneal nerve Tibial nerve • Videos Injuries Injuries to superior Gluteal nerve • Supplies Gluteus medius, minimus & tensor fascia lata • Positive Trendelenberg Test • Patient presents with Waddling gait or Gluteal gait IM injections and Sciatic nerve damage The surface markings of the sciatic nerve IM injections and Sciatic nerve damage Dislocation of femoral head can injure sciatic nerve Significant Injuries to main sciatic nerve will have gross neurological impairment Common peroneal nerve is at a risk of damage at the neck of the fibula Differentiation of peroneal nerve components Nerve Common peroneal nerve Deep peroneal nerve Superficial peroneal nerve Motor Sensory Weakness TA, EDL, EHL, EDB, EHB, PT, PL, PB Lateral calf and dorsum of foot (sparing lateral and plantar foot) Ankle dorsiflexion and eversion Toe extension TA, EDL, EHL, EDB, EHB, PT Area between great and second toes Ankle dorsiflexion and partial eversion > inversion Toe extension PL, PB Lateral calf and dorsum of foot Ankle eversion (sparing lateral foot) TA = tibialis anterior, PL = peroneus longus, PB = peroneus brevis, EDB = extensor digitorum brevis, EHL = extensor hallucis longus, EDL = extensor digitorum longus, PT = peroneus tertius, EHB = extensor hallucis brevis History • A man who met with an RTA suffers from pelvic fractures. He complains of weakness and numbness of the right leg. His right foot drops when walks. Examination findings • Muscle weakness of: – Foot dorsiflexion – Foot eversion – Toe extension • Muscle Strength is normal in: – Foot plantar flexion – Foot inversion – Toe flexion • There is slight weakness in knee flexion SENSORY LOSS Localization Weakness Ft Dorsiflex Grt toe ext Toe ext Foot eversion L4,5 Muscle TIB ANT EHL EDL, EDB FIB L, B Nerve FIB FIB FIB Knee flex Mult TIB/Fib L5S1S2 GASTROC, SOLEUS FDL/FDB POST TIB TIB S1,2 TIB TIB L5,S1 L4,5 Spared Foot plant flex Toe flex Foot inv Root L4,5 L5 L4,5 FIB Common Fibular (Peroneal) Nerve Common Fib Superficial Fibular Fib Longus Fib Brevis Short head BF Deep Fibular Tib Ant EHL Fib Tertius EDB Final Diagnosis Sciatic neuropathy with selective involvement of the fibular (peroneal) nerve fibers at the level of the pelvis Radiculopathy Injuries at nerve root level (e.g. by herniating intervertebral disc) – Sensory impairment (numbness) in the area of the skin supplied by the nerve root (dermatome) – Weakness in muscles supplied by the nerve root (myotome) – Ex. Cervical and lumbar radiculopathy Cervical radiculopathy • Neck pain • Numbness over shoulder, upper limb and or Muscle weakness depend on the root involved Lumbar radiculopathy Back Pain & sensory , motor impairment depend on the nerve root involved Mononeuropathy • Dysfunction of a single peripheral nerve (due to injury or lesion) – Weakness in muscles supplied by the nerve – Sensory loss in the area of the skin supplied by the cutaneous branches of the nerve Ex. median nerve, common fibular, radial