Referred Pain

Sections


Summary

Definition

  • Referred pain is the physiologic process whereby internal organs manifest with body surface pain.

DIAPHRAGM

  • C3, C4, and C5 innervate the diaphragm (C3, C4, C5 keep the diaphragm alive!)
  • The diaphragm refers sensation to the C3, C4, C5 dermatomes: the neck, shoulders, and upper lateral arm.

HEART

  • T1 to T5 innervate the heart.
  • The T1 to T5 dermatomes cover the chest and medial upper arm and forearm, so myocardial ischemia (heart pain) is felt along the left side of the chest and inside of the left arm. Note that cardiac pain does not extend into the fingers (supplied by C6 to C8).

UMBILICUS

  • T10 dermatome covers the umbilicus (T10 innervates the appendix), and thus, appendicitis is first felt at the umbilicus.

When the appendicitis becomes somatic and moves to the right lower quadrant.

Full Text

  • Here, we will draw a map for referred pain, which is the physiologic process whereby internal
    organs manifest with body surface pain.
  • First, draw the trunk and upper left arm.
  • Indicate that innervation of the diaphragm comes from C3, C4, and C5.
  • We remember this innervation pattern by the mnemonic: C3, C4, C5 keeps the diaphragm alive!
  • Thus, the diaphragm refers sensation to the C3, C4, C5 dermatomes: the neck, shoulders, and upper lateral arm.
  • Next, let's consider the visceral map for the heart.
  • Show that, generally, the T1 to T5 spinal nerves innervate this organ.
  • The T1 to T5 dermatomes cover the chest and medial upper arm and forearm, and thus, in accordance
    with the referred pain principle, myocardial ischemia is commonly felt along the left side of the chest and inside of the left arm.
    • Note that cardiac pain does not classically extend into the fingers, which are supplied by the C6 to C8 spinal nerves; this knowledge can help you distinguish a heart attack from left upper extremity nerve damage (from polyradiculopathy
      or plexopathy).
  • Finally, consider that the appendix is innervated by T10.
    • The T10 dermatome covers the umbilicus, and thus, appendicitis is first felt as a vague, painful sensation at the umbilicus; it is only later, when the appendicitis worsens, that the pain becomes somatic and moves to the right lower quadrant.