Dermatomes

Question 1

What is a dermatome?

Answer 1

A dermatome is a specific area of skin located on the body that is innervated by a specific nerve root.

Question 2

Nerves leaving the spinal cord divide into motor and sensory, what is an alternative name for these nerves?

Answer 2

Sensory nerves are also known as afferent nerves, they carry information from the peripheral nervous system to the central nervous system and provide sensation to specific areas of the skin.

Efferent nerves on the other hand are also known as motor nerves. They’re primary function is to innervate voluntary muscles that are derive from myotomes.

Question 3

How many dermatomes are there?

Answer 3

There are 30 numbered dermatomes which relate to the spinal level that they originate from.

Question 4

Why doesn’t C1 have a dermatome?

Answer 4

C1 does not contain a sensory nerve root

Question 5

C1 inneravates which muscles?

Answer 5

Sub-occipitals

Question 6

What is the clinical term for a nerve root compression that generates a referral pattern of pain?

Answer 6

Radiculopathy

Question 7

If the C6 Nerve Root is compressed it may cause someone to feel numbness in which area of the body? Which myotome/ muscle would it effect?

Answer 7

The Thumb, The musculocutaneous nerve, BBC muscles

Question 8

Name two forms of stenosis which can contribute towards a compression of a nerve root.

Answer 8

Spinal stenosis and foramina stenosis

Question 9

What is the name for a vertebra which has displaced anteriorly and posteriorly?

Answer 9

Spondylolisthesis and Retrolisthesis

Question 10

Which nerve roots exit above the levels of the corresponding vertebrae?

Answer 10

C1 to C7

Question 11

Which nerve root exits below the corresponding vertebrae?

Answer 11

C8

Question 12

If you have a disc condition between, for example, C5 and C6, then which nerve root would be affected?

Answer 12

C6