Makindo Medical Notes.com

Related Subjects: |Neurological History taking |Cortical functions |Motor System |Sensory System |Mental state Examination |Speech and Language Exam |Cranial nerves and examination |Assessing Cognition

Introduction

• Paralysis is a very useful and hard sign of neurological disease.
• One must immediately ask where is the lesion
• This can be done by working out of the weakness is UMN or LMN
• One must look at the pattern of weakness

Pattern of Weakness

• Same side face,arm,leg: Intracranial lesion - tumour , stroke, MS
• Same side arm,leg, opposite side face: Brainstem - tumour , stroke, MS
• Same side arm,leg : Intracranial or cervical
• Both arms and legs weak and face spared: Cervical cord

Graphic

UMN and LMN signs

• LMN: Weakness, Reduced or absent reflexes, down-going plantar, wasting and fasciculations. The lesion is distal to the anterior horn cell.
• UMN: Hyperreflexia, extensor plantar, increased tone. The lesion is proximal to the anterior horn cell.

Upper limb Inspection

• Always initially start looking for wasting, scars and fasciculations.
• Feel muscle bulk and look for wasting. If marked quads wasting could measure thigh circumference.
• Check symmetry of findings. Palpate muscles - are they tender or fasciculation or wasted
• Pronator drift: Ask the patient to hold arms out straight ahead horizontally with palms up and close eyes. If the affected side slowly pronates and the elbow flexes and drifts down is a subtle sign of an UMN lesion on that side

Assessment of Tone

• Assess upper limb tone in the wrist and elbow. Get the patient to relax and distract him with irregular movements. Different types of altered tone associated with disease
• Spasticity - increased tone seen with pyramidal weakness classically is variable with velocity and distance joint moved. High tone often gives way and has been called "clasp knife". Best seen in forearm supination in the upper limb and knee flexion in the lower limb.
• Extrapyramidal disease gives a more constant increase in tone through all movements and is called "lead pipe" rigidity. Seen classically with Parkinson's disease. If there is a superimposed tremor the increased tone may be called "cogwheel"
• Gegenhaltan - an erratic increase in tone in those with frontal lobe dysfunction also called "paratonia"

Power - Upper limb

• Shoulder abduction before 90 degrees is supraspinatus muscle and suprascapular nerve and C5 root
• Shoulder abduction beyond 90 degrees is deltoid supplied by axillary nerve C5
• Shoulder adduction is by multiple muscles/nerves and generally C7 root and adds little
• Shoulder external rotation is by infraspinatus and suprascapular nerve and C5 root
• Shoulder internal rotation is subscapularis muscle and subscapular nerve and C5 root
• Elbow flexion biceps muscle and Musculocutaneous nerve and C6 and some C5 roots
• Elbow flexion half pronated (holding a cup) is radial nerve supply to brachioradialis and is most C6 and some C5
• Elbow extension is by triceps supplied by radial nerve and C7 root
• Wrist flexion flexor carpi radialis (Median) Flexor carpi ulnaris (ulnar) and C7/8 roots
• Wrist extension extensor carpi radialis longus and external carpi and ulnaris radial nerve/posterior interosseous C7
• Finger flexion: Median and Ulnar nerves to long and short flexors
• Finger extension: extensor digitorum Posterior interosseous nerve (radial) C7
• Finger abduction: Ulnar nerve (dorsal interossei) T1 (DAB)
• Finger adduction: Ulnar nerve (palmar interossei) T1 (PAD)
• Thumb opposition: Opponens pollicis Median nerve T1
• Thumb flexion: Flexor pollicis brevis Median nerve T1
• Thumb adduction: Adductor pollicis T1

Individual nerves - Motor

• Median nerve: Opponens pollicis Abduction and opposition of thumb and thumb flexion and T1 nerve root
• Ulnar nerve: Flexion of the ring and little finger (medial two lumbricals) and adduction and abduction of fingers (dorsal interossei) and thumb adduction T1
• Radial nerve: "Wrist drop" Wrist extension by long and short extensors C8

Palpating Nerves : Enlarged nerves

• Leprosy - is mainly sensory enlarged ulnar and radial and ulnar and others
• Hereditary neuropathies e.g. Charcot Marie Tooth disease - mainly motor
• Neurofibromatosis
• Refsum's disease - phytanic acid deficiency, autosomal recessive
• Amyloidosis

Reflexes - Tests the integrity of the normal reflex arc and the effect of higher centres on it

• Biceps C5(6)
• Supinator C(5)6
• Triceps C6/7
• Hoffman reflex is hyperreflexia - flick DIP of the index finger and thumb adducts
• Record as -,+,++,+++

Coordination

• Finger-Nose - test for coordination: Touch tip of the nose and then my finger, eyes open. Examiner should move their finger around as a moving target. Ask the patient to touch nose with eyes closed to assess proprioceptive deficit as a cause of ataxia
• Rapid movements: Touch left palm with the right palm and then supinate right hand to touch left palm with dorsum of the right hand. Alternative quickly and then switch sides. Difficulty called dysdiadochokinesia and is a sign of cerebellar disease
• Increased suggests a loss of inhibition from higher pathways with an Upper motor lesion
• Be able to draw a reflex arc with afferent and efferent pathways
• Absence suggests a lower motor neurone lesion e.g. neuropathy such as Guillain-Barré syndrome
• Absent reflexes: Neuropathy e.g. GBS, nerve compression, disease of the neuromuscular junction, Myopathy

Lower limb Inspection

• look for deformity, scars, wasting, fasciculations
• Pick up leg asking first to check if it is not painful and look at heel for ulcers and sole of feet
• Look for neuropathic or vascular or ulcers or Charcot's joint deformity, inverse champagne bottle legs (CMT)

Tone / Clonus

• Assess tone by first rolling the leg and then a sudden lift up at the knee and see if the ankle comes off the bed.
• Could suggest increased tone and a UMN lesion.
• Get a feel for tone at ankle and knee and don't forget to test for clonus either now or after having demonstrated increased reflexes

Power - lower limb

• Hip flexion Femoral nerve Iliopsoas: "Pull knee up" L1/2 roots
• Hip extension: Gluteus maximus Inferior gluteal nerve "Force thigh down onto bed" L5/S1 roots
• Knee flexion: L5/S1 hamstrings Sciatic nerve "bend knee"
• Knee extension: L3/4 Femoral nerve quadriceps "straighten knee"
• Ankle plantar flexion: S1 sciatic gastrocnemius" push foot down"
• Ankle dorsiflexion: L4/5 Sciatic via common peroneal nerve. Tibialis anterior "pull foot up"
• Toe flexion: S1/2 "Curl down toes" sciatic small muscles of foot
• Toe extension: L5 S1 Sciatic nerve toe extensors "curl toes up"

Reflexes

• Knee : L3/L4
• Ankle : S1/S2
• Babinski - rub pen along lateral border and toes should curl
• If reflexes are increased look for clonus at the ankle and patella
• If reflexes are not found then try using reinforcement

Coordination

• Heel shin test: Same as finger nose in many ways but using feet
• Run right heel along left shin and lift off and place on left patella and run it down again. Alternate sides.
• Can even ask the patient to touch examiners finger with large toe
• Ask patient to place one heel on alternate patella with eyes closed

Heel-toe gait

• A useful test of motor dysfunction - formerly a test of acute alcohol intoxication a well-known depressant of cerebellar function
• Patient walks with heel to toe. Look for ataxia. A useful tests of neurological impairment

Interpretation

• Patterns of weakness to recognise(once a weakness is found use tone and reflexes to determine if UMN or LMN)
• Pyramidal e.g. stroke: Upper limb extensors weaker than flexors, lower limb flexors weaker than extensors
• Proximal weakness: Unable to raise arms above head, get out of the chair - suggests a myopathic weakness or Myasthenia or Guillan-Barre syndrome
• Fatigable weakness : Myasthenia gravis
• Distal symmetrical weakness: Peripheral neuropathy or Inclusion body myositis
• Hemiparesis Face/arm/leg : suggests contralateral intracranial pathology
• Hemiparesis Arm and Leg: Contralateral intracranial pathology or cervical cord pathology
• Weakness both legs - suggests cord or cauda equina damage
• Hemiparesis and contralateral cranial nerve signs suggest brainstem lesion e.g. right IIIrd nerve and C/L hemiparesis

Motor Roots

• C5 - radial side of forearm and reduced biceps reflex and power
• C6 - deficit in the thumb and first finger and decreased bicep and brachioradialis
• C7 - deficit in middle and ring finger and reduced triceps jerk
• C8 - Deficit in little finger and reflexes are normal
• T1 - T12 - pain in distribution but no weakness. Can cause chest wall pain. Mistaken as cardiac pain.
• L2 - sensory deficit lateral and anterior thigh weak psoas and quadriceps. Reflexes normal
• L3 - sensory deficit lower medial thigh weak psoas and quadriceps. Reduced knee jerk
• L4 - sensory deficit medial lower leg. Decreased knee jerk
• L5 - Lateral lower leg. Weak. No reflex abnormality
• S1 - lateral foot and with weak gastrocnemius. Reduced ankle jerk

Key movements of the Upper limb

Key movements of the lower Limb