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Lower limb neurological examination

Diagnosing in neurology

Ask yourself throughout if the pathology is:

  • Unilateral/bilateral UMN (pyramidal weakness)
  • Unilateral LMN (weakness depends on lesion)
  • Bilateral LMN (distal weakness)
  • Proximal weakness

By the time you get to the sensory exam you should know what you are expecting to find and use it to confirm or narrow down differentials (see neurology differentials).

Introduction

  • Wash hands
  • Introduce self
  • Ask Patient’s name, DOB and what they like to be called
  • Explain examination and obtain consent
  • Expose patient’s legs (to underwear or shorts)

Inspection

  • General inspection
    • Look at the patient in general: posture, habitus, other signs of neurological conditions (e.g. hypomimia, facial muscle wasting)
    • Look around bed, for example you may see: mobility aids, orthoses
  • Gait – first ask if they can walk and if they need assistance/aids
    • Normal walking
      • Hemiplegic = unilateral UMN
      • Spastic = bilateral UMN
      • Foot drop = LMN
      • Ataxic = cerebellar
      • Waddling = myopathic
      • Festinating = parkinsonian
    • Heel-to-toe walking if stable (ataxia = cerebellar pathology)
    • Stand on heels and then toes (tests distal power)
    • Romberg’s test (only if steady): ask patient to close eyes and assess their stability (reduced stability = sensory ataxia due to proprioceptive deficit)
  • Local inspection – look closely at the legs
    • Tremors
    • Muscles: muscle wasting – in general and then look closely for plantar foot wasting and for dorsal foot guttering (LMN lesion); fasciculations (LMN lesion); associated bony deformity (e.g. pes cavus)
    • Skin: neurofibromas, café au lait spots, scars (including small muscle biopsy scars)

Tone

  • Tone: patient should lie relaxed with legs flat. With one hand either side of the knee, roll each leg from side to side
    • ↑tone, i.e. foot remains in line with knee = UMN lesion
    • ↓ tone = LMN lesion
  • Spasticity: place hand under the patient’s knee and briskly lift it up (spasticity, i.e. foot kicks out involuntarily = UMN lesion)
  • Clonus: hold the sole of the patient’s foot in one hand, and elevate it while holding their ipsilateral knee flexed in the other hand. Forcefully flex the ankle a few times quickly, and then hold it firmly in the flexed position. Feel for involuntary, rhythmic beats of gastrocnemius contraction (>5 beats = UMN lesion).

Power

Test one joint at a time and compare sides. Always support the joint being tested with one hand (use it as a lever). Use all your strength!

Hip flexion (L2/L3)Patient should raise their leg off the bed with knee fully extended. Stabilise contralateral hip joint with one hand and push down on the quadriceps just above the knee of the raised leg. ‘Don’t let me push your leg down.’
Hip extension (L4/L5)With the same leg still raised to about 30˚, stabilise the ipsilateral hip joint with one hand and hold the underside of the patient’s knee with the other hand. ‘Push my hand down into the bed.’
Knee extension (L3/L4)With the patient’s knee flexed to about 90˚, stabilise the joint with one hand and hold the anterior side of their ankle with your other hand and try to push it towards them. ‘Try and kick your leg out. Don’t let me push it towards you.’
Knee flexion (L5/S1)In the same position, but holding the posterior side of their ankle, try and pull it away. ‘Try and pull your heel towards your bottom. Don’t let me pull it away.’
Ankle dorsiflexion (L4/L5)With their leg straight on the bed and their ankle actively dorsiflexed, stabilise the ankle with one hand. Make a fist with your other and use the dorsal side of your fist to try and push the patient’s foot downwards. ‘Point your foot up towards your head. Don’t let me push it down.’
Ankle plantar-flexion (S1/S2)With their leg straight on the bed and their ankle actively plantar-flexed, try to pull it up with your fingers around the ball of the patient’s foot. ‘Point your foot downwards towards the bottom of the bed. Don’t let me pull it up.’
Big toe extension (purely L5)With their big toe actively flexed, isolate the toe’s metatarsophalangeal joint with one hand and try to push it down with the index and middle fingers of your other hand. ‘Point your big toe up towards your head. Don’t let me push it down.’

MRC power grades

5 = full power

4 = some resistance

3 = GRAVITY

2 = gravity eliminated

1 = flicker of muscle contraction

0 = nothing.

Reflexes

Hold the tendon hammer by the end of the plastic rod to make a pendulum-like swing. Ensure the patient is fully relaxed. If you cannot elicit a reflex, ask them to close their eyes and grit their teeth when you strike the tendon.

Reflexes may be brisk, normal, reduced or absent.

  • Patellar (L3, 4 kick the door): with the knee relaxed in passive flexion (hold it up with your left wrist under the patient’s knee), locate the tibial tuberosity and inferior border of the patella, and strike the patellar tendon that lies between these.
  • Ankle (S1, 2 in the shoe): externally rotate the patient’s leg and flex their knee (so their lower leg rests over their contralateral shin). Hold their foot with your left hand and gently dorsiflex their ankle. Strike the Achilles tendon with the hammer in your right hand. NB: to test their left ankle reflex, move to the base of the bed.
  • Plantar (Babinski) reflex: warn the patient and then, using an orange stick, gently scrape the plantar surface of their foot in a semi-circle from the heel, around the lateral edge and to the ball of the big toe (big toe ↑ = UMN lesion; big toe ↓ = normal).

Co-ordination

  • Heel-to-shin test
    • Ask the patient to touch their heel to their contralateral knee
    • Then ask them to slide their heel down the tibia to their contralateral ankle
    • Now ask them to move it back up, through the air, to their contralateral knee again
    • Repeat this about three times for each side
    • Lower limb ataxia = cerebellar pathology

Sensation

For pain and light touch, first show the patient how each should feel on their sternum, then start distally. If there is distal sensory loss or if from the motor exam you suspect ‘glove and stocking’ sensory loss, or a sensory-level, test from distal to proximal in 2-3 straight lines. If distal sensation is intactor if from the motor exam you suspect nerve/nerve root pathology, test dermatomes ± peripheral nerves:  

Pain (spinothalamic)

  • Use neurological pin
  • ‘Close your eyes and say “yes” every time you feel the pin. Please also let me know if it feels blunt.’

Light touch (dorsal column)

  • Touch the skin with a cotton wool ball (don’t stroke it)
  • Close your eyes and say “yes” every time you feel the cotton wool.’

For the modalities below, start distally and only move proximally if the patient cannot feel you:

Proprioception (dorsal column)

  • Hold the proximal phalanx of the patient’s big toe with your index finger above and your thumb below
  • Move the distal phalanx up and down with the thumb and index finger of your other hand, holding it on each side
  • Show the patient the up and down positions
  • Now ask them to close their eyes and repeatedly wiggle the distal phalanx up and down. Stop in one position and ask them if it is up or down. Do this three times.
  • If they get it wrong, move to the metatarsophalangeal joint, then the ankle, and so on until they can correctly state the position

Vibration (dorsal column)

  • Twang the prongs of a 128Hz (long) tuning fork
  • Place the round base on their sternum to demonstrate how it should feel
  • Now ask them to close their eyes and hold it over the interphalangeal joint of their big toe. Ask if they can feel it vibrate and when it stops vibrating. (Grip the prongs to stop the vibration yourself.)
  • If they cannot sense the vibration, move to the metatarsophalangeal joint, then medial malleolus, then tibial tuberosity, and so on until they can

Temperature (spinothalamic)

  • Use the prongs of the tuning fork on the patient’s sternum to test if they can identify them as cold
  • If so, touch a prong horizontally to the skin on the dorsum of the distal foot and ask if the patient can feel it as cold. If not, move proximally up the leg until they can

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Lower limb dermatomes

To complete

  • Thank patient and restore clothing
  • ‘To complete my examination, I would examine the cranial nerves and perform an upper limb neurological examination.’
  • Summarise and suggest further investigations you would consider after a full history

Clinical features of upper and lower motor neuron lesions

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Why don’t you test your knowledge?

List 3 causes of a bilateral upper motor neurone lesion

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Which conditions may result in a unilateral upper motor neurone lesion?

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What are the causes and clinical features of a Brown-Sequard syndrome?

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Try an OSCE examination stations!

  1. Lower limb exam
  2. Charcot Marie Tooth
  3. Motor neurone disease
  4. And there’s lots more here!

Picture references

Charcot-Marie-Tooth foot: Benefros, 2004. Licenced under the Creative Commons Attribution-Share Alike 3.0 Unported license.

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