Referred pain

Question 1

In simple clinical terms, What is the definition of referred pain?

Answer 1

pain perceived as
occurring in a region of the body topographically distinct from the region in
which the actual source of pain is located

Question 2

In nerological terms, what is the definition of referred pain?

Answer 2

pain perceived as arising or occurring in a region of the body innervated
by nerves or branches of nerves other than those that innervate the actual
source of pain.

Question 3

What region of the brain localises pain?

Answer 3

The somatotrophic map of the S1 somatosensory cortex

Question 4

WHat corresponds to S1 somatosensory cortex representation

Answer 4

Spinal segmental level

Question 5

What do spinal segmental levels localise?

Answer 5

Surface dermatomes

Question 6

What happens when a spinal nerve root is directly activated?

Answer 6

Referred to dermatome as radicular pain

Question 7

Are deeper structures innervated by the same nerve root that innervates the dermatome?

Answer 7

no

Question 8

Which fibre contains the c fibre sensory afferents needed for transmitting pain signals from MUSCLES?

Answer 8

THe motor nerve of the specific muscle contains proprioceptive c fibres and nociceptive c fibres. This means it also has the same nerve root. This is how we get myotomal maps of sensory innervation

Question 9

What is proprioception

Answer 9

perception or awareness of the position and movement of the body

Question 10

What is nociception

Answer 10

Nociception is the neural processes of encoding and processing noxious stimuli. A noxious stimulus is “an actually or potentially tissue damaging event.” It is a prerequisite for nociception, which itself is a prerequisite for nociceptive pain.

Question 11

What are the four origins of noxious input that may refer to the dermatome

Answer 11

1. Muscle via nociceptive afferents that run with motor nerve
2. Joint via nociceptive afferents from joint structures
3. Bone via periosteal nociceptive afferents
4. Visceral input via visceral “SNS” autonomic fibres

Question 12

what kind of referred pain involves dermatomes

Answer 12

Radicular referred pain

Question 13

What kind of referred pain involves myotomes

Answer 13

Myofascial referred pain

Question 14

What kind of referred pain involves sclerotomes

Answer 14

Bone/joint referred pain

Question 15

What kind of referred pain involves Viscerotomes

Answer 15

Viscerotomes

Question 16

How is radicular referred pain stimulated

Answer 16

Pathological actovation of the dorsal root ganglion at a spinal segmental level, classically from a disc prolapse causing “sciatica”

Question 17

How is referred somatic pain caused

Answer 17

Bibres distal to dorsal root ganglion innervate spinal ligament/facet joints, annulus. Pathology here causes nociceptive input converging in dorsal horn with cutaneous sensory afferents

Pain referred distally along nerve root distribution

Question 18

How is myofascial referred pain caused?

Answer 18

Nociceptive afferent activation within muscle converges onto dorsal horn of spinal cord at same segmental level as motor suppy originates

Question 19

how is referred visceral pain caused?

Answer 19

nOCICEPTIVE AFFERENTS FROM GUT COALESCE IN VISCLERAL PLEXI