The document discusses referred pain, defined as pain perceived at a location distinct from the site of the painful stimulus, often due to visceral organ irritation. It outlines the mechanisms behind referred pain, including the dermatomal rule and convergence-projection theory, and highlights how understanding referred pain is crucial for clinical diagnosis, as it may be the only sign in certain visceral ailments. Additionally, it provides examples of commonly noted patterns of referred pain linked to specific organs.

2. Group Members
1) Muhammad Haroon 240
2) Muhammad Hassaan Khalid 241
3) Rao Jahanzaib 242

3. Referred pain

4. Referred pain
 Definition
 Physiological Basis/ Mechanism
 Different Examples
 Importance

5. Definition
 pain perceived at a location other than the site of the painful
stimulus.
 Irritation of a visceral organ frequently produces pain that is felt
not at that site but in some somatic structure that may be a
considerable distance away. Such pain is said to be referred to
the somatic structure.
 also called reflective pain

6. Referred pain mechanism
 2 mechanisms
 Dermatomal rule
 Convergence–projection theory

7. Referred pain mechanism
(Dermatomal rule)
 Dermatomal rule
- When pain is referred, it is usually to a structure that developed
from the same embryonic segment or dermatome as the structure in
which the pain originates. This principle is called dermatomal rule
 FOR INSTANCE:
 the heart and the inner aspect of left arm
 Testicle & ureter+kidney(from urogenital ridge)

8. Referred pain mechanism
(Convergence– projection theory)
 Convergence– projection theory
 Second mechanism for referred pain may be convergence
of somatic and visceral pain fibers on the same second-
order neurons in the dorsal horn that project to the
thalamus and then to the somatosensory cortex (Figure 10–
3). This is called the convergence– projection theory.

9. Referred pain mechanism
(Convergence– projection theory)
 Somatic and visceral neurons converge in lamina I–VI of the
ipsilateral dorsal horn
 Neurons in lamina VII receive afferents from both sides of the
body
explains referral of pain to the side opposite that of the source of pain
i. e. affected organ.

10. Convergence– projection theory

11. Convergence– projection theory

12. Convergence– projection theory
If prolongation of visceral stimulus
facilitation of the somatic fiber endings
stimulate the second order neurons
brain interprets activity in a pathway as
arising from somatic sources
Referred pain in somatic area
The somatic nociceptive fibers normally do not activate the
second-order neurons. But……..

13. Note
 However, sites of referred pain are not stereotyped, and
unusual reference sites occur with considerable frequency.
 FOR INSTANCE
 Cardiac pain, for instance, is usually referred to Upper chest/left limb
But it may be referred to the right arm, the abdominal region, or even
the back and neck.

14. ..........

15. Visceral Pain
Pain from the different viscera of the abdomen and chest .
transmitted through small type C pain fibers
Causes of True Visceral Pain :
1. Ischemia
2. Chemical Stimuli
3. Spasm of a Hollow Viscus
4. Overdistention of a Hollow Viscus

16. Localization of Visceral Pain
Pain from the different viscera is frequently difficult to localize
because :
1. patient’s brain does not know from firsthand experience that
the different internal organs exist.
2. sensations from the abdomen and thorax are transmitted
through two pathways to the central nervous system—the
true visceral pathway and the parietal pathway.

17.  True visceral pain is transmitted via pain sensory fibers within the
autonomic nerve bundles, and the sensations are referred to surface
areas of the body often far from the painful organ.
 parietal sensations are conducted directly into local spinal nerves
from the parietal peritoneum, pleura, or pericardium, and these
sensations are usually localized directly over the painful area.

18. Localization of Referred Pain
Transmitted via Visceral Pathways.
 person generally localizes visceral in the dermatomal segment
from which the visceral organ originated in the embryo.
 Pain from the viscera is frequently localized to two surface
areas of the body at the same time because of the dual
transmission of pain through the referred visceral pathway and
the direct parietal pathway.

19. Examples
 Upper chest/left limb
o Myocardial ischaemia
 Right tip of scapula
o Liver, gallbladder
 Left shoulder
o Thoracic diaphragm,
Spleen (Kehr's sign, lung
 Back
o Pancreas
 Umblicus
o Small intestine ;appendex

21. Importance
 Knowledge of the different types of referred pain is important in
clinical diagnosis because in many visceral ailments the only
clinical sign is referred pain.