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Dermatome vs. Myotome: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on November 28, 2023
A dermatome is an area of skin innervated by sensory fibers from a single spinal nerve root, while a myotome is a group of muscles primarily innervated by motor fibers from a single spinal nerve root.

Key Differences

A dermatome refers to an area of skin that is mainly supplied by sensory nerve fibers from a single spinal nerve. In contrast, a myotome is a group of muscles that a single spinal nerve root primarily innervates.
Each spinal nerve contributes to a specific dermatome, covering a distinct part of the body, which is useful in diagnosing nerve damage. Myotomes, on the other hand, are crucial for understanding motor function, as each is associated with specific muscle movements.
In clinical settings, testing dermatome sensitivity can help locate nerve or spinal cord injuries. Similarly, examining myotomes can help identify motor nerve or spinal cord issues by assessing muscle strength and movement.
Dermatomes follow a predictable pattern along the body, aligning with specific spinal nerves, which aids in the mapping of sensory nerve damage. Myotomes also have a specific distribution, with each spinal nerve influencing certain muscle groups.
Abnormalities in dermatome sensation can indicate neurological problems, such as herniated discs or shingles. Abnormalities in myotome function, such as weakness or paralysis, can point to motor neuron diseases or spinal cord injuries.

Comparison Chart


Sensory nerve supply to skin
Motor nerve supply to muscles

Clinical Use

Diagnose sensory nerve damage
Assess motor nerve function


Follows a predictable skin area distribution
Corresponds to specific muscle groups

Indicative Conditions

Sensory abnormalities suggest nerve/spinal issues
Motor abnormalities indicate muscular/neurological issues


Aligned with spinal nerves
Aligned with spinal nerves

Dermatome and Myotome Definitions


A mapped area of skin used in neurologic diagnosis.
The numbness in her leg was traced to a specific dermatome.


A muscle segment associated with specific spinal nerves.
Damage to the L4 spinal nerve affected the myotome of his leg.


A region of skin served by one spinal nerve.
After the surgery, he experienced decreased sensation in the dermatome of his thigh.


A group of muscles innervated by a single spinal nerve root.
The myotome testing showed weakness in muscles supplied by the C5 nerve.


A skin segment corresponding to a spinal nerve.
Shingles often affects a single dermatome, causing a painful rash.


A distribution of muscle function related to a spinal nerve.
The physical exam included myotome testing to assess motor function.


A cutaneous area connected to a spinal root.
The dermatome map helped identify the affected nerve root.


A collection of muscles controlled by a single spinal nerve.
Neurological examination focused on the myotome related to her symptoms.


An area of skin innervated by sensory fibers from a single spinal nerve.
The dermatome on his arm was tested for sensitivity to diagnose nerve damage.


A segment of musculature linked to spinal nerve innervation.
The injury to his spinal cord affected the myotome governing arm movement.


(Anatomy) An area of skin innervated by sensory fibers from a single spinal nerve.


A segmental mass of mesoderm in a vertebrate embryo that differentiates into skeletal muscle.


(Medicine) An instrument used in cutting thin slices of the skin, as for skin grafts.


A muscle or group of muscles derived from one somite and innervated by a single segment of a spinal nerve.


(Embryology) The part of a mesodermal somite from which the dermis develops.


A knife for dividing muscle during surgery.


An instrument used surgically to remove a thin slice of skin for grafting


In vertebrate embryonic development, a group of tissues formed from any particular one of the somites that develop into the body wall muscle. myomere.


An area of skin which is innervated by afferent nerve fibers coming to a single posterior spinal root.


In neurology, a group of muscles innervated from a particular spinal segment; the division of innervation reflects the embryology of the various somites.


The cutis plate.


A surgical instrument for performing myotomy.


A surgical instrument used to cut very thin slices of skin


A muscular segment; one of the zones into which the muscles of the trunk, especially in fishes, are divided; a myocomma.


What is a myotome?

A group of muscles primarily controlled by motor fibers from a single spinal nerve root.

What is a dermatome?

A specific skin area innervated by sensory fibers from a single spinal nerve.

Are myotomes important for understanding muscle function?

Yes, they help in identifying which spinal nerves control specific muscle groups.

How does nerve damage manifest in myotomes?

Nerve damage can lead to muscle weakness or paralysis in the affected myotome.

What does a myotome assessment involve?

It involves testing muscle strength and movement to evaluate motor nerve function.

Do dermatome patterns vary among individuals?

The basic pattern is consistent, but slight individual variations can occur.

Can myotome testing pinpoint spinal cord levels?

Yes, it helps in identifying the level of spinal cord or nerve root involvement.

What conditions can affect myotomes?

Conditions like spinal cord injuries, herniated discs, or motor neuron diseases.

What role do myotomes play in physical therapy?

They guide therapists in targeting specific muscle groups for rehabilitation.

Are dermatomes related to specific spinal nerves?

Yes, each dermatome is associated with a specific spinal nerve.

How do dermatome abnormalities present clinically?

As changes in skin sensation like numbness or tingling in the affected area.

How are dermatomes used in medical diagnosis?

By testing sensitivity in specific dermatomes, doctors can locate nerve or spinal injuries.

Can a single spinal nerve affect multiple dermatomes?

Generally, one spinal nerve corresponds to one dermatome, but there can be some overlap.

Can dermatome testing be used for all age groups?

Yes, it's applicable across different ages for neurological assessment.

How specific are myotome assessments in diagnostics?

They are quite specific in localizing motor nerve or spinal cord dysfunctions.

How are dermatome maps used?

They are used to visually represent the sensory innervation of the skin.

Can myotome assessments detect early nerve damage?

They can be indicative of early stages of motor nerve impairment.

Do dermatome issues always indicate spinal problems?

Not always, but they are a key indicator of potential spinal or nerve issues.

Are there any limitations to myotome testing?

Yes, overlapping muscle innervation can sometimes complicate the interpretation.

Is there a dermatome for every spinal nerve?

Yes, each spinal nerve has a corresponding dermatome.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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