Myotomes
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Definition[edit | edit source]
The anatomical term myotome refers to the muscles served by a spinal nerve root. A myotomes is therefore a set of muscles innervated by a specific, single spinal nerve.The term is also used in embryology to describe that part of the somite which develops into the muscles.[1]
There are 31 spinal nerves.Each vertebrae has a spinal nerve. The nerves are categorized by the vertebra which house them. There are:
8 cervical nerves
12 thoracic nerves
5 lumbar nerves
5 sacral nerves
1 coccygeal nerve
16 of these 31 nerves has a specific myotome that controls voluntary muscle movement. [2]
Most muscles in the limbs receive innervation from more than one spinal nerve root, and are hence comprised of multiple myotomes. For example, the biceps brachii muscle flexes the elbow. It is innervated by the musculocutaneous nerve, which is innervated by C5, C6 and C7 nerve roots. All three of these spinal nerve roots can be said to be associated with elbow flexion.
The list below details which movement has the strongest association with each myotome:
C5 – Elbow flexion
C6 – Wrist extension
C7 – Elbow extension
C8 – Finger flexion
T1 – Finger abduction
L2 – Hip flexion
L3 – Knee extension
L4 – Ankle dorsiflexion
L5 – Great toe extension
S1 – Ankle plantarflexion[3]
Purpose[edit | edit source]
An essential part of neurological examination when suspecting radiculopathy as muscle strength in a particular myotome may help in identifying at which level a nerve root compromised.
Technique[edit | edit source]
Describe how to carry out this assessment technique here
Evidence[edit | edit source]
Provide the evidence for this technique here
Resources[edit | edit source]
add any relevant resources here
References[edit | edit source]
- ↑ Wikipedia. Myotome. Available from: https://en.wikipedia.org/wiki/Myotome (last accessed 22.4.2019)
- ↑ Study.com. What are myotomes. Available from: https://study.com/academy/lesson/what-are-myotomes-definition-testing.html (last accessed 22.4.2019)
- ↑ Teach me anatomy. Myotomes. Available from: https://teachmeanatomy.info/the-basics/embryology/myotomes/ (last accessed 22.4.2019)
