[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Clinical exam](https://durgical.com/en/clinical-exam/) › [Nervous system](https://durgical.com/en/clinical-exam/#a-neuro) › Motor examination: bulk, tone and strength grading

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# Motor examination: bulk, tone and strength grading

- Exam technique

A check of muscle bulk, stiffness or floppiness of the muscles, and strength graded from 0 to 5.

Updated 2026-11-01

**See it in 3D:** [Motor cortex](https://durgical.com/en/anatomy/precentral-gyrus/) · [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/) · [Grey matter of the cord](https://durgical.com/en/anatomy/grey-matter-of-spinal-cord/) · [Neck nerve roots](https://durgical.com/en/anatomy/anterior-root-of-spinal-nerve/)

## Key points

- MRC scale: 0 nothing, 1 contraction without movement, 2 gravity eliminated, 3 against gravity, 4 against some resistance, 5 normal.
- Clasp-knife spasticity (velocity-dependent, gives way suddenly): upper motor neuron.
- Lead-pipe or cogwheel rigidity, equal throughout the range: basal ganglia (parkinsonism).
- Marked wasting and fasciculations: lower motor neuron.
- Symmetric proximal weakness (trouble rising from a chair, Gowers sign): myopathy; distal weakness: neuropathy.

## What it is

The motor exam assesses three things in order: bulk (muscle mass, wasting and fasciculations), tone (resistance to passive movement) and strength, graded on the Medical Research Council scale from 0 to 5. The pattern of weakness (one side of the body, proximal, distal, one nerve or root territory) points to the site of the lesion.

## Landmark anatomy

- Upper motor neuron: motor cortex (precentral gyrus) and the corticospinal tract, which crosses at the pyramidal decussation in the medulla.
- Lower motor neuron: anterior horn cells of the spinal cord and brainstem motor nuclei, with their root and peripheral nerve.
- The basal ganglia and cerebellum modulate tone and smoothness of movement without causing true weakness.

## Technique, step by step

- Expose the limbs and compare both sides: bulk, wasting, fasciculations and abnormal movements.
- With the patient relaxed, passively flex and extend the elbow, wrist, knee and ankle at different speeds to judge tone.
- Roll the leg on the bed or lift the knee briskly to detect hypotonia or spasticity.
- Strength: ask the patient to hold a position while the examiner pushes; compare each muscle with the other side.
- In the arm test shoulder, elbow, wrist and fingers; in the leg test hip, knee, ankle and big toe.
- Grade each group from 0 to 5 and record the side.
- Functional tests: rising from a chair without the hands, walking on toes and heels, pronator drift.

## Medical Research Council (MRC) muscle strength scale

| Grade | What is seen |
| --- | --- |
| 0 | No visible or palpable contraction |
| 1 | Visible or palpable contraction, no joint movement |
| 2 | Moves the joint only with gravity eliminated |
| 3 | Moves against gravity but not against the examiner's resistance |
| 4 | Moves against gravity and some resistance |
| 5 | Normal strength against full resistance |

## Abnormal findings

- Spastic hemiparesis with hyperreflexia: stroke or another lesion of the opposite corticospinal tract.
- Symmetric ascending weakness with areflexia: Guillain–Barré syndrome.
- Fatigable weakness of the eyelids and proximal muscles without sensory loss: myasthenia gravis.
- Cogwheel rigidity with a resting tremor: parkinsonism.

## Common errors

- The range between grades 4 and 5 is wide; many examiners record 4− and 4+.
- Pain, poor effort or not understanding the instruction can mimic weakness.
- Judging tone while the patient is tense; tone is assessed only with the muscles relaxed.

## Memory aid

'Zero to two can't beat gravity, three beats gravity, four beats a bit more, five beats it all': gravity is the line at 3.

## Test yourself

Think of the answer, then tap the question to see it.

## What MRC grade is a muscle that moves against gravity but not against resistance?

Grade 3.

## How does spasticity differ from rigidity?

Spasticity is velocity-dependent and gives way suddenly (clasp-knife), typical of the upper motor neuron; rigidity is equal through the whole range (lead-pipe or cogwheel), typical of the basal ganglia.

## What does symmetric proximal weakness without sensory loss suggest?

A myopathy or a neuromuscular junction disorder; the patient struggles to rise from a chair or climb stairs.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/clinical-exam/motor-examination-bulk-tone-and-strength-grading/)

## See it in 3D

The structures of Durgical's 3D anatomy where it is found.

- [Motor cortex](https://durgical.com/en/anatomy/precentral-gyrus/)
- [Spinal cord](https://durgical.com/en/anatomy/spinal-cord/)
- [Grey matter of the cord](https://durgical.com/en/anatomy/grey-matter-of-spinal-cord/)
- [Neck nerve roots](https://durgical.com/en/anatomy/anterior-root-of-spinal-nerve/)

## Related

- [The neurological examination: order and screening exam](https://durgical.com/en/clinical-exam/the-neurological-examination-order-and-screening-exam/)
- [Deep tendon reflexes and their grading](https://durgical.com/en/clinical-exam/deep-tendon-reflexes-and-their-grading/)
- [Pronator drift](https://durgical.com/en/clinical-exam/pronator-drift/)
- [Upper vs lower motor neuron syndrome](https://durgical.com/en/clinical-exam/upper-vs-lower-motor-neuron-syndrome/)
- [Parkinsonian syndrome](https://durgical.com/en/clinical-exam/parkinsonian-syndrome/)

## Related conditions

- [Ischaemic stroke](https://durgical.com/en/conditions/ischaemic-stroke/)
- [Guillain-Barré syndrome](https://durgical.com/en/conditions/guillain-barre-syndrome/)
- [Myasthenia gravis](https://durgical.com/en/conditions/myasthenia-gravis/)
- [Parkinson disease](https://durgical.com/en/conditions/parkinson-disease/)
- [Peripheral neuropathy (diabetic and other)](https://durgical.com/en/conditions/peripheral-neuropathy/)

[← All of the clinical exam](https://durgical.com/en/clinical-exam/)

Educational content on the clinical exam; it is learned and practised under supervision. It does not replace assessment by a health professional and is not for self-diagnosis.

Sources: [How To Assess Muscle Strength](https://www.msdmanuals.com/professional/neurologic-disorders/neurologic-examination/how-to-assess-muscle-strength) (MSD Manual Professional Edition, 2024); [How To Assess the Motor System](https://www.msdmanuals.com/professional/neurologic-disorders/neurologic-examination/how-to-assess-the-motor-system) (MSD Manual Professional Edition, 2024); [16.4 The Sensory and Motor Exams](https://openstax.org/books/anatomy-and-physiology-2e/pages/16-4-the-sensory-and-motor-exams) (OpenStax, Anatomy and Physiology 2e, 2022).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/clinical-exam/motor-examination-bulk-tone-and-strength-grading/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/clinical-exam/motor-examination-bulk-tone-and-strength-grading/