Lower limb neurological examination frequently appears in OSCEs. You’ll be expected to pick up the relevant clinical signs using your examination skills. This guide provides a clear step by step approach to performing a neurological examination of the lower limb, with an included video demonstration.
The main point of a neurological examination is to localise where in the nervous system the problem is. This can seem daunting, but with practice it is relatively straightforward. The most basic localisation question you have to think about during the upper and lower limb examination is:
Is there an upper motor neuron (UMN) lesion? – i.e. in the brain or spine
Or is there a lower motor neuron lesion (LMN)? – i.e. in the nerve roots, peripheral nerve, neuromuscular junction or muscle
The following is a summary of some basic UMN and LMN signs that you should be looking out for during the upper and lower limb examinations:
|UMN signs||LMN signs|
|Inspection||No fasciculation or significant wasting (may be some disuse atrophy or contractures)||Wasting and fasciculation of muscles|
|Pronator drift||May be present||May be some drift/movement of arm(s) if weak or de-afferented, but not pronator|
|Tone||Increased (spasticity) +/- ankle clonus||Decreased (hypotonia) or normal|
|Power||Classically a “pyramidal” pattern of weakness (extensors weaker than flexors in arms, and vice versa in legs)||Different patterns of weakness, depending on cause e.g. classically a proximal weakness in muscle disease, a distal weakness in peripheral neuropathy|
|Reflexes||Exaggerated or brisk (hyper-reflexia)||Reduced or absent (hyporeflexia or areflexia)|
|Plantar reflexes||Upgoing/extensor (Babinski positive)||Normal (downgoing/flexor) or mute (i.e. no movement)|
Confirm patient details – name / DOB
Explain the examination
Expose patient’s legs – underpants or shorts
Ask if the patient currently has any pain
- Tendon hammer
- Cotton wool
- Tuning fork (128Hz)
Observe for clues around the bed – walking stick / wheelchair
General appearance – any limb deformity or posturing?
- Wasting of muscles
- Involuntary movements – dystonia/chorea/myoclonus
- Fasciculation – lower motor neurone lesions
- Tremor – Parkinson’s
1. Ask the patient to walk to the end of the room and back – assess posture, arm swing, stride length, base, speed, symmetry, balance and for abnormal movements.
Some common types of gait abnormality to observe for:
- Ataxic: broad-based and unsteady. As if drunk. From cerebellar pathology or a sensory ataxia. Often won’t be able to tandem gait either. With a sensory ataxia, the patients watch their feet intently to compensate for proprioceptive loss. In a cerebellar lesion, may veer to one side.
- Parkinsonian: small, shuffling steps, stooped posture and reduced arm swing (initially unilateral). Several steps taken to turn. Appears rushed (festinating) and may get stuck (freeze). Hand tremor may be noticeable.
- High-stepping: (either unilateral or bilateral) caused by foot drop (weakness of ankle dorsiflexion). Also won’t be able to walk on their heel(s).
- Waddling gait: shoulders sway from side to side, legs lifted off ground with the aid of tilting the trunk. Caused by proximal lower limb weakness, e.g. myopathy.
- Hemiparetic: one leg held stiffly and swings round in an arc with each stride (circumduction).
- Spastic paraparesis: similar to above but bilateral – both are stiff and circumducting. Feet may be inverted and “scissor”.
2. Tandem (heel-to-toe) gait – ask to walk in a straight line heel-to-toe – an abnormal heel-to-toe test may suggest weakness, impaired proprioception or a cerebellar disorder
3. Heel walking – assesses dorsiflexion power
- Ask the patient to stand with their feet together and eyes closed
- Observe the patient (ideally for 1 minute)
- Positive test – loss of balance (swaying without correction/falling over) – this suggests a sensory ataxia (proprioceptive deficit)
- It’s important to stand close by the patient during this test to stop them falling over!
Ask the patient to keep their legs fully relaxed and “floppy” throughout your assessment.
1. Leg roll – roll the patient’s leg and watch the foot – it should flop independently of the leg
2. Leg lift – briskly lift leg off the bed at the knee joint – the heel should remain in contact with the bed
3. Ankle clonus:
- Position the patient’s leg so that the knee and ankle are slightly flexed, supporting the leg with your hand under their knee, so they can relax.
- Rapidly dorsiflex and partially evert the foot
- Keep the foot in this position
- Clonus is felt as rhythmical beats of dorsiflexion/plantarflexion (>5 is abnormal)
Assess one side at a time and compare like for like.
Remember to stabilise the joint whilst testing power.
Use the MRC muscle power assessment scale for scoring muscle strength.
Flexion (L1/2) – “raise your leg off the bed and stop me from pushing it down”
Extension (L5/S1) – “stop me from lifting your leg off the bed”
ABduction (L4/5) – “push your legs out”
ADduction (L2/3) – “squeeze your legs in”
Flexion (S1) – “bend your knee and stop me from straightening it”
Extension (L3/4) – “kick out your leg”
Dorsiflexion (L4) – “keep your legs flat on the bed…cock your foot up towards your face…don’t let me push it down “
Plantarflexion (S1/2) – “push down like on a pedal”
Inversion (L4) – “push your foot in against my hand”
Eversion (L5/S1) – “push your foot out against my hand”
Extension (L5) – “don’t let me push your big toe down”
Deep tendon reflexes
Ensure the patient’s lower limb is completely relaxed.
Hold at the end of the tendon hammer handle and allow gravity to aid a good swing.
If a reflex appears absent: make sure the patient is fully relaxed and then perform a reinforcement manoeuvre – ask the patient to hook their hands together in a monkey grip and try to pull them apart, whilst you hit the tendon.
1. Knee jerk (L3/4)
2. Ankle jerk (L5/S1)
3. Plantar reflex (S1):
- Run a blunt object along the lateral edge of the sole of the foot, moving towards the little toe, then medially under the toes
- Observe the great toe
- Normal result = Flexion of the great toe and flexion of the other toes
- Abnormal (Babinski sign) = Extension of the great toe and spread of the other toes – upper motor neuron lesion
Light touch sensation
Assesses dorsal/posterior columns and spinothalamic tracts.
1. The patient’s eyes should be closed for this assessment
2. Touch the patient’s sternum with the cotton wool wisp to confirm they can feel it
3. Ask the patient to say “yes” when they are touched
4. Using a wisp of cotton wool, gently touch the skin (don’t stroke)
5. Assess each of the dermatomes of the lower limbs
6. Compare left to right, by asking the patient if it feels the same on both sides
Assesses spinothalamic tracts.
Repeat the previous assessment steps, but this time using the sharp end of a neurotip.
If sensation is reduced peripherally, assess from a distal point and move proximally to identify ‘stocking’ sensory loss (peripheral neuropathy). If necessary, keep going all the way up the leg and truck until normal sensation is felt. This may reveal a “sensory level”, which is suggestive of a spinal lesion (e.g. if there is abnormal sensation up to the level of the umbilicus, this suggests a spinal lesion at around T10).
Assesses dorsal / posterior columns
1. Ask patient to close their eyes
2. Tap a 128 Hz tuning fork
3. Place onto patient’s sternum and confirm patient can feel it buzzing
4. Ask patient to tell you when they can feel it on their foot and to tell you when it stops buzzing
5. Place onto the distal phalanx of the great toe
6. If sensation is impaired, continue to assess more proximally – e.g. proximal phalanx
Dorsal / posterior columns
1. Hold the distal phalanx of the great toe by its sides
2. Demonstrate movement of the toe “upwards” and “downwards” to the patient (whilst they watch)
3. Then ask patient to close their eyes and tell you if you are moving the toe up or down
4. If the patient is unable to correctly identify direction of movement, move to a more proximal joint (big toe > ankle > knee > hip)
Heel to shin test –“put your heel on your knee, run it down your shin, lift it up and repeat”
An inability to perform this test may suggest loss of motor strength, proprioception or a cerebellar disorder.
To complete the examination…
Suggest further assessments and investigations
- Cranial nerve examination
- Upper limb neurological examination
- Further imaging if indicated – e.g. Lumbar spine MRI
Dr Gemma Maxwell
Neurology Registrar (ST6)