Differentials
Presenting Feature | What might it be? | What might I find? | |
Weakness |
Stroke (CVA) |
RF: prior CVA, AF, HTN, diabetes, CVD, smoking, obesity.
Sudden onset, unilateral lower limb weakness +/- other stroke symptoms e.g., facial weakness, dysphasia, ataxia/vertigo. |
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Motor neurone disease |
Typically older, male with family history.
Slow onset weakness, often upper limbs before lower limbs or face. UMN/LMN signs. UMN: inc tone, brisk reflexes, plantars up. LMN: reduced tone, slow reflexes, weakness, wasting, fasciculations. |
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Guillain-Barré syndrome |
Can affect any patient but most common adult males.
Bilateral, symmetrical ascending weakness which starts distally. Usually triggered by infection e.g., EBV, CMV, campylobacter. May involve sensory, autonomic & respiratory systems. Peripheral —> ascending weakness, sensation & reflex loss. |
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Common peroneal nerve palsy |
Cause: trauma, external pressure e.g., crossed legs, cast, or brace.
Motor: Foot drop, weak dorsiflexion/eversion. Sensory loss: lateral lower leg, dorsum foot & 1st webspace. |
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Myasthenia Gravis |
Association with thymoma, inc. incidence in women aged <40 / men > 60.
Weakness exacerbated by activity and improved with rest. Proximal limb and bulbar/small facial muscles most affected. |
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Numbness |
Lumbosacral radiculopathy (sciatica) |
RF: increasing age, known back injury or spinal stenosis.
Commonly caused by disc herniation in lumbosacral spine. Back/lower limb pain with numbness, paraesthesia +/- weakness in a dermatomal or myotomal distribution e.g., L5, S1. |
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Peripheral neuropathy |
Causes: alcohol excess, B12 deficiency, cancer, CKD, diabetes, drugs, vasculitis, Charcot-Marie-Tooth disease.
Sensory (and motor) loss in peripheries e.g.,. hands & feet in a ‘glove & stocking distribution’. If suspected, examine distal —> proximal to find sensory ‘level’ |
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Multiple sclerosis |
RF: young adult (<50), female sex..
Lesions disseminated in time & space so symptoms change over time. May include numbness or paraesthesia in lower limbs. |
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Meralgia Paraesthetica |
Compression of lateral femoral cutaneous nerve.
Upper lateral thigh numbness, tingling. Worse standing up. |
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Gait Abnormality |
Parkinsonian |
Associated with core symptoms of PD – tremor, rigidity, bradykinesia.
Shuffling gait, stooped posture, many quick small steps to compensate for shuffle (festinating gait), hesitancy, ↓arm swing. |
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High stepping |
Common peroneal nerve palsy, L4/5 root irritation, sciatica.
High step develops as compensation for foot drop. |
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Hemiplegic |
Unilateral UMN lesion e.g.,stroke, tumour, MS. Unilateral symptoms.
Upper limb flexion, lower limb extension and circumduction. |
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Diplegic |
Bilateral UMN lesion e.g., cerebral palsy, MS, cord lesion.
Lower limbs affected > upper limbs.. Valgus knees. Bilateral symptoms. Hip/knee flexion, ankle plantar-flexion and internal rotation. |
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Ataxic |
Cerebellar lesion, MS, sensory neuropathy, vestibular pathology, ETOH.
Unsteady, slow, broad based gait. Unable to heel-toe walk. |
Checklist
Preparation | Wash – Name – Explain | |
Position patient lying on the couch at 45° | ||
Appropriate exposure of lower limbs | ||
General Inspection | Body habitus | |
Obvious asymmetry to lower limbs | ||
Clues in bed space | ||
Inspection | Gait | |
Heel-toe walking | ||
Romberg’s test | ||
Symmetry | ||
Scars | ||
Muscle wasting | ||
Fasciculations | ||
Involuntary movements | ||
Tone | Leg roll | |
Leg lift | ||
Clonus | ||
Power | Hip flexion | |
Hip extension | ||
Knee flexion | ||
Knee extension | ||
Ankle dorsiflexion | ||
Ankle plantarflexion | ||
Big toe extension | ||
Reflexes | Knee reflex | |
Ankle reflex | ||
Plantar reflex | ||
Sensation | Ask patient to close their eyes | |
Demonstrate on sternum | ||
Fine touch | ||
Pain | ||
Vibration | ||
Proprioception | ||
Co-ordination | Heel-shin | |
Finishing | Re-cover patient | |
Wash hands |
Explanation
Preparation
Wash, name, explain:
- Wash your hands
- Introduce yourself by name and role
- Check the patient’s name and date of birth
- Explain the procedure and get consent
“I have been asked to perform a neurological examination of your lower limbs. This involves testing some of the nerves in your legs by checking movement and sensation. You can ask me to stop at any time. Are you happy for me to do that?”
Position the patient reclining on the couch at 45°.
Ensure the patient’s legs are fully exposed.
General Inspection
Look at the patient and around the bed space for useful signs:
- Body habitus – is there evidence of frailty, wasting, or cachexia?
- Obvious asymmetry when looking at and comparing the lower limbs from the end of the bed
- Clues around the bed space (e.g., mobility aids, wheelchair, medications)
Inspection
Begin the inspection of the lower limbs by asking the patient to stand (if able) and assessing the following:
- Gait
- Heel-toe walking
- Romberg’s test
The assessment of gait is a key part of lower limb neurological examination, and a lot of information can be gained from observing a patient walking. Ensure that you check that the patient is able to walk before beginning a gait assessment.
First, assess the patient walking as they normally would, i.e., ask the patient to walk to the other side of the room and back to you. Observe for any of the following gait abnormalities:
- Parkinsonian – hesitant, shuffling, multiple small fast steps (festinating), difficulty initiating movement and changing direction. Associated with the core components of Parkinson’s Disease: tremor, rigidity & bradykinesia. Referred to as festinant gait.
- High-stepping – associated with foot drop, high-stepping to compensate and prevent foot dragging on the floor
- Hemiplegic – unilateral symptoms, upper limb held in flexion; lower limb: hip and knee extended, ankle plantarflexed, hip circumducts to move the foot. Also referred to as spastic gait
- Diplegic – bilateral symptoms, upper limbs affected less than lower limbs, hip and knee slightly flexed, knees in valgus posture, ankles plantarflexed and internal rotated. Also referred to as scissoring gait
- Ataxic – unsteady, broad-based, uncoordinated, difficulty walking in a straight line and with heel-toe walking
Next, ask the patient to walk in a straight line, placing one foot in front of the other with their heels and toes touching. Observe if they are able to keep their balance.
Carry out Romberg’s test by asking the patient to stand with their feet together and their eyes closed. Ensure you can support them if they begin to fall by standing near them with your arms outstretched. Do not carry out Romberg’s test if the patient is very unsteady or at high risk of falling.
If the patient is steady with their eyes open, but unsteady when their eyes are closed, this indicates sensory ataxia and loss of proprioception. This is because vision and proprioception are essential for maintaining balance; if vision is removed (by closing the patient’s eyes) and proprioception is impaired, the patient will become unsteady.
Ask the patient to get back onto the couch. Look at the patient’s legs and compare both sides, making note of any of the following:
- Symmetry – do the legs appear similar? Is there a unilateral deformity or difference in posture?
- Scars – from trauma or previous surgery
- Muscle wasting – assess muscle bulk of the legs, quadriceps bulk, dorsal foot muscle wasting (guttering)
- Fasciculations – small involuntary muscle twitches
- Involuntary movements – larger movement (e.g., pseudoathetosis or choreiform movement)
Tone
To assess tone, warn the patient that you are going to be moving their legs. Check that they do not have pain in their legs. Ask them to try to stay as relaxed as possible, and let their legs go floppy whilst you take the weight of the limb and move it for them.
With the patient’s legs outstretched, gently roll the thigh and compare the tone to the opposite leg. Whilst moving the legs assess for resistance to movement. Is there increased tone (hypertonia) or reduced tone (hypotonia)? If there is increased tone; determine if the hypertonia is spasticity (velocity-dependent, direction-dependent, may reduce later in movement), or rigidity (not velocity- or direction-dependent).
Place your hands behind the patient’s knee and lift the leg briskly upwards and observing whether the leg remains extended and the heel lifts off the bed (increased tone).
Hold the patient’s mid–foot in one hand and their posterior calf in the other. Dorsiflex the ankle briskly and feel for any beats of clonus (any repeated dorsiflexion felt whilst holding the foot). Up to 5 beats is within normal limits; more than 5 beats indicates clonus/increased tone.
Repeat the above for both legs.
Power
Assess power in the lower limb by asking the patient to perform active movement against resistance. Assess power in all lower limb myotomes, comparing the right and left legs. Ensure the joint being tested is isolated to accurately interpret the examination findings.
Power is graded according to the MRC Scale:
0 – No movement
1 – Flicker of movement
2 – Active movement with gravity eliminated
3 – Active movement against gravity
4 – Active movement against gravity and resistance
5 – Normal movement
The following movements are assessed:
- Hip flexion: Ask the patient to lift their leg off the bed, keeping the knee extended. Try to push the patient’s leg down and ask them to resist. L1/2 myotomes
- Hip extension: Ask the patient to push their straight leg down into the bed, try to flex their hip and ask them to resist. L5/S1 myotomes
- Knee flexion: Ask the patient to bend their knees to around 90°. Try to extend the patient’s knees and ask them to resist. L5/S1 myotomes
- Knee extension: Ask the patient to straighten their legs out, try to flex their knees and ask them to resist. L3/4 myotomes.
- Ankle dorsiflexion: Ask the patient to pull their ankles back towards their body. Try to push the patient’s foot downwards in plantarflexion and ask them to resist. L4/5 myotomes
- Ankle plantarflexion: Ask the patient to point their toes downwards, try to push the patient’s foot upwards in dorsiflexion and ask them to resist. S1/2 myotomes
- Big toe extension: Ask the patient to pull their big toe back towards their body, try to push the patient’s toe downwards in plantarflexion and ask them to resist. L5 myotome
Reflexes
There are three reflexes to examine in the lower limb: (There are several different ways to elicit the knee and ankle reflexes and the below is a suggestion only – learn what suits you best):
- Knee reflex: Ask the patient to sit with their lower legs hanging over the edge of the couch and to relax as much as possible. Locate the patellar tendon just inferior to the patella and tap with the tendon hammer. L3/4 myotomes.
- Ankle reflex: With the patient’s legs in the same position as above, dorsiflex the ankle with one of your hands by gently pushing the sole of the patient’s foot upward. Leave your hand on the sole of the foot and tap the achilles tendon with the tendon hammer, feeling for a plantarflexion jerk against your hand. S1 myotome.
- Plantar reflex: Run your thumbnail upwards along the lateral sole of the patient’s foot from heel to metatarso-phalangeal joints. Observe the first movement of the toes, specifically the great toe for plantar/dorsiflexion. L5/S1 myotomes.
Assess each reflex in turn, noting whether the knee and ankle tendon reflexes are normal, brisk, reduced, or absent; and whether the plantar reflex is down–going (normal), up–going (UMN lesion) or equivocal. If you are unsure or the examination findings are unclear you can reinforce and exaggerate the tendon reflexes by asking the patient to clench their teeth.
Sensation
There are several sensory modalities to be examined including:
- Fine touch
- Pain
- Vibration sense
- Proprioception
Temperature is another sensory modality but is infrequently examined in an OSCE situation
To examine fine touch and pain sensation, ask the patient to close their eyes. Examine light touch first with cotton wool. Demonstrate the sensation of the cotton wool by touching it on the patient’s sternum to familiarise them with the sensation. Ask the patient to respond by saying ‘Yes’ when they feel the touch of the cotton wool on their leg.
Examine sensation by testing each of the dermatomes in the lower limb in turn (see diagram*), comparing both sides before moving on to the next dermatome. If the peripheral dermatomes are more affected than the proximal dermatomes, a ‘glove and stocking’ distribution of sensory loss may be suspected. A sensory level can be ascertained by starting at the toes and checking sensation in increments proximally until sensation returns to normal.
Repeat this process with a neuro–tip to assess pain sensation.
To examine vibration sense, with the patient’s eyes still closed, vibrate a 128Hz tuning fork, demonstrating the sensation to the patient by placing the vibrating base of the tuning fork on their sternum so that they know what they are feeling for. Then test vibration sense on the most distal joint of the big toe – the interphalangeal joint (IPJ). Ask the patient to say yes if they can feel the vibration and compare both sides. If the patient cannot feel it, test the next proximal joint until the sensation is perceived.
To examine proprioception, ask the patient to close their eyes and hold the patient’s big toe by the proximal phalanx with one hand and the distal phalanx with the other hand (your thumb and index finger on medial/lateral side of there patient’s toe). Flex the IPJ and tell the patient this is what “down” feels like, extend the IPJ and tell the patient this is what “up” feels like. Then move the joint and ask the patient to tell you if the joint is “up” or “down”.
Co-ordination
The heel–shin test is used to examine co–ordination in the lower limb. Ask the patient to bend the knee of one leg and place the heel of the foot on the knee of the opposite leg. Ask them to slide the heel down the shin to the ankle then lift their heel off and replace on the knee. Ask them to repeat this several times, observing for smoothness, accuracy, and any difficulty or misplacement. Repeat with the other leg.
Finishing
Thank the patient and allow them to cover themselves. Wash your hands.
Depending on the examination findings you may wish to carry out neurological examination of the cranial nerves and upper limbs; as well as carry out further investigations including blood tests, nerve conduction studies, CT or MR scan of the head or spine.
[*Illustrations – coming 2025]
Last updated Dec 2024
Head to members.zerotofinals.com for practice OSCE stations, including an interactive checklist, specific cases and clinical findings.