Referred Pain

Question 0

Be able to trace the pathway of these fibers from the viscera into the CNS.

Answer 0

SEE PAGE 29..
visceral afferent fiber passes from the target organ back to the prevertebral ganglion, back through the splanchnic n. to the paraverterbral ganglion, up through the white ramus communicans into the ventral ramus of the spinal nerve, and back into the dorsal root (where the cell body of this fiber resides in the dorsal root spinal ganglion)

Question 1

What specific fibers are responsible for relaying pain from the viscera?

Answer 1

Visceral afferent fibers

Question 2

Along what structure is this visceral pain referred and where is it felt?

Answer 2

The pain is referred out along the ventral ramus. this fiber briefly travels in and is felt in the dermatome supplied by the ventral ramus.

Question 3

What is meant by proximal-distal referred pain?

Answer 3

The injury proximal to the CNS but the pain is felt distal from the site of the injury.

Question 4

Be able to give at least one example of proximal-distal referred pain.

Answer 4

Herniated disc– the injury occurs at the intervertebral foramen of L5 but the pain is felt distally along the ventral ramus of L5 down to the dorsal and ventral surface of the foot.

Question 5

What is meant by somatic/embryological referred pain.

Answer 5

The diaphragm arises embryologically in the cervical region so is innervated by the phrenic nerve. during development, the diaphragm descends to the region dividing the thorax from the abdomen. injury/stimulation to the pleura over the diaphragm can result in pain being referred to the skin over the neck/ear.

Question 6

What is meant by visceral/somatic referred pain.

Answer 6

Pain from the viscera is referred to a body dermatome distant from the site of the pain.

Question 7

Be able to give at least one example of visceral/somatic referred pain.

Answer 7

Cardiac infaction- pain originates in the myocardium, passes through the cervical nerves to the paravertebral trunk, back into the white ramus communicans and into the ventral ramus of T1-T4. The pain is referred out along the dermatomes of T1-T4, which is the skin of the thorax and down the medial side of the left upper limb.

Question 8

In visceral/somatic referred pain why is pain from myocardial infarction relayed down the medial side of the left arm?

Answer 8

The pain is on the left side as the heart is an organ of the left side of the thorax.

Question 9

The area around the umbilicus is supplied with sensory innervation by which vertebral level?

Answer 9

T10