Run the lower limb neurological examination in one order every time: inspection, tone, power, reflexes, coordination, sensation and gait. Grade power on the published 0 to 5 scale, test the key muscles that the international spinal cord injury standards define, and compare the two sides at every step.

Key takeaways

  • The ISNCSCI worksheet grades power from 0, total paralysis, to 5, full range against full resistance.
  • Its lower limb key muscles are hip flexors L2, knee extensors L3, ankle dorsiflexors L4, long toe extensors L5 and ankle plantar flexors S1.
  • Sensory grading on the same worksheet is 0 absent, 1 altered and 2 normal.
  • NICE CKS describes Babinski's sign as positive when the toes extend and fan outwards on stimulating the lateral sole, which may indicate an upper motor neurone lesion.
  • NICE CKS treats weakness below MRC grade 3 as a red flag: the patient cannot move the leg against resistance or gravity.

What is the examiner marking at this station?

The Intercollegiate blueprint marks a physical examination station out of 20 across four domains: clinical and technical skill carries 8 marks, and clinical knowledge and its application, communication and professionalism carry 4 marks each. The station also gets a separate global rating of pass, borderline or fail.

More than half the marks therefore sit outside your knowledge of the condition, so a silent but technically correct examination scores poorly. You are signalled at six minutes of the nine to present your findings, so the sequence has to finish inside six.

The examiner is marking a reproducible sequence, clear instructions to the patient and a conclusion: upper motor neurone, lower motor neurone, or neither.

Speak your instructions the way you would to a patient, because the station is scored on communication as well as technique.

How should you start?

Introduce yourself, gain consent, expose both legs and ask the patient to lie supine. Ask about pain and about walking aids in the room.

Then inspect both legs together.

  • Skin, for scars, trophic changes and ulcers
  • Muscle bulk and symmetry, looking for wasting
  • Fasciculations, which suggest a lower motor neurone problem
  • Posture and any abnormal position of the foot

How do you assess tone in the legs?

Ask the patient to relax, then roll the leg from side to side and lift the knee suddenly, watching the heel.

Test for ankle clonus by rapidly dorsiflexing the ankle with the knee slightly flexed, and report whether clonus is present and whether it is sustained rather than counting to a threshold.

How should you test power, and how is it graded?

Test each movement against your own resistance, comparing sides, and grade on the 0 to 5 scale published on the ISNCSCI worksheet.

  • 0 is total paralysis and 1 is a palpable or visible contraction
  • 2 is full range with gravity eliminated and 3 is full range against gravity
  • 4 is full range against gravity and moderate resistance in a muscle specific position
  • 5 is full range against gravity and full resistance, as expected of an otherwise unimpaired person

Use the published key muscles as your minimum set: hip flexors for L2, knee extensors for L3, ankle dorsiflexors for L4, long toe extensors for L5 and ankle plantar flexors for S1.

How do you examine the reflexes?

Position the limb so the muscle is relaxed and slightly stretched, support the weight of the leg, and strike the tendon with a tendon hammer allowed to fall under its own weight.

If a reflex appears absent, reinforce by asking the patient to clench the teeth or interlock the fingers and pull, then repeat before recording it as absent.

Finish with the plantar response. NICE CKS describes Babinski's sign as positive when the toes extend and fan outwards after stimulating the lateral part of the sole, which may indicate an upper motor neurone lesion.

Which sensory modalities should you test?

Test the two pathways separately and demonstrate each on the sternum first so the patient knows what normal feels like.

  • Light touch and pin prick, working up dermatome by dermatome and comparing sides
  • Vibration, with a tuning fork on a bony prominence, moving proximally if it is absent distally
  • Proprioception, holding the sides of the great toe and moving it up or down with the eyes closed
  • Grade sensation as the worksheet does: absent, altered or normal

How do you test coordination and gait?

Ask the patient to run the heel of one foot down the opposite shin and repeat, comparing sides, then ask them to walk if it is safe.

Gait completes the examination. NICE CKS notes that a high-stepping gait with an inability to lift the foot suggests weakness of ankle dorsiflexion, which is the finding most often missed on the couch.

What are the most common mistakes at this station?

  • Testing power without ever grading it, so the examiner cannot hear a severity
  • Failing to relax the patient before testing tone, then reporting spasticity
  • Recording an absent reflex without attempting reinforcement
  • Testing sensation without demonstrating normal first, or asking leading questions
  • Skipping gait because the patient is on a couch, when it is often the most informative part

How should you finish?

Offer to examine the upper limbs, the spine and the sacral segments, and to test for a sensory level if a cord lesion is possible.

Then say what your findings mean: distal wasting with absent reflexes and fasciculations points to a lower motor neurone lesion, while increased tone, clonus and an extensor plantar response point to an upper motor neurone lesion.

The MRCS Part B Questions bank has a lower limb neurological examination station at /Sample-Questions.