Viscero-Visceral Referral in Anatomy

Viscero-Visceral Referral

• One sensitized organ can cause sensitization of another organ when they share a common sensory afferent nerve or have afferent 'cross-talk' in the dorsal horn (DH).
• Causes of viscero-visceral referral:
  • The heart and gallbladder share overlapping (T5) afferent pathways, leading to reduced angina attacks and coronary revascularization when gallbladder calculi are treated.
  • The renal system and uterus share overlapping afferent nerve pathways (T10-L1 afferents), resulting in reduced renal colics when hormonal therapy is used for dysmenorrhoea.

Viscero-Somatic Referral

• Visceral pain causes referred somatic pain, requiring thorough history, examination, and investigations to determine its origin.
• Characteristics of somatic referred pain:
  • Better localized
  • Sharper
  • Less likely to be associated with emotional and neurovegetative signs
• Somatic referred pain can be associated with:
  • Hyperalgesia, resulting in increased sensitivity in muscles, skin, and subcutaneous (SC) tissue innervated by the somatic spinal nerve.
• Examples of pain syndromes with viscero-somatic referral:
  • Renal colic: hypersensitive lumbar muscles (quadratus lumborum, obliques) and pain in the flank and groin, even after calculi have been passed.
  • Acute myocardial ischaemia: pain in the chest radiating down the arm (C8-T1 dermatomes).

Somatic-Viscero Referral

• Similar mechanisms to those of viscero-somatic referral.
• Characteristics of somatic-viscero referral:
  • Deep palpation of muscle can reproduce visceral pain in people with profound muscle hyperalgesia.
• Examples of somatic-viscero referral:
  • Deep palpation in the flank and groin can elicit visceral pain from the genitourinary system, even after a renal calculi has been passed.
  • Treatment of somatic referred pain can improve visceral pain.