Head zones

In the 1890s, the English neurologist Sir Henry Head (1861-1940) discovered defined areas of the skin that were characterized by increased sensitivity(allodynia) in visceral diseases. The hyperalgesia phenomena are detectable in the dematomas associated with the (diseased) visceral organs of the same metamer. Usually on the contralateral side. The zones are called Head's zones after their discoverer.

Head's zones are congruent with dermatomes, i.e. the areas of skin that are each supplied by a single spinal nerve. However, a single dermatome can also affect neighboring dermatomes by radiating into the surrounding area. Hyperalgesia can even occur in the entire affected half of the body (hemiplegia). Furthermore, only circumscribed areas of the affected dermatome may exhibit hyperalgesia.

Segmental skin hyperalgesia and hyperaesthesia in diseases of internal organs. The skin zones with the sensory supply from the same spinal cord segment as the diseased internal organs are affected. The visceral pain impulse is transmitted via a viscerocutaneous reflex. It is also known as "transmitted pain".

In clinical diagnostics, this phenomenon is also referred to as the head zone test (also known as the Kalchschmidt test).

Visceral pain can also be projected onto muscle sections of the corresponding nerve segment (Mackenzie zone).

Examples of Head's projections include radiating pain in myocardial ischemia (projection of pain onto a variable area extending from the ear to the navel) or in inflammation affecting the parietal pericardium (pericardial pain).

Head had already referred to the existence of"maximum points". Here there are points of reference to Chinese medicine. Two important groups of acupuncture points, the diagnostically relevant Mu and Shu points, largely correspond spatially and functionally with maximum points of Head's zones. A comparison of Head's work with the Huang Di Neijing (Inner Classic of the Yellow Thearch) and the Zhen Jiu Jia Yi Jing (Systematic Classic of Acupuncture and Moxibustion), two of the oldest surviving Chinese sources on acupuncture, revealed astonishing parallels between the two concepts. On the one hand, the location of the points and on the other, the functional aspects.

Chinese medicine uses Mu and Shu points not only diagnostically but also therapeutically.

Assignment of dermatome and organs

• heart: C 3-4, Th 1-5, predominantly right, also left arm
• Aorta thoracica: C 3-4, Th 1-7, bilateral
• Pleura: Th 2-12 of the respective half of the body (ipsilateral)
• Lungs: C 3-4, ipsilateral
• Oesophagus: Th 1-8, both sides
• Stomach: Th (5) 6-9, left
• Liver and bile ducts: Th (5) 6-9 (10), right
• Pancreas: Th 6-9, left side
• Duodenum:Th 6-10, right
• Jejunum: Th 8-11, left
• Ileum:Th 9-11, on both sides
• Appendix, proximal colon: Th 9-10, L 1, right
• Distal Colon:Th 9 - L 4, left
• Rectum:Th 9 - L 4, left
• Kidney and ureter, Th 9 - L 1 (2), ipsilateral
• Adnexes:Th 12 - L 4, ipsilateral
• Peritoneum:Th 5-12, bilateral
• Spleen:Th 6-10, left

In fact, Head's findings were already not new in his time. To be precise, they are already more than 2000 years old. They are firmly anchored in Chinese medicine. However, Head's work led Western medicine to focus more intensively on the segmental-reflector relationships between visceral organs and the skin, the viscero-cutaneous reflexes.

1. Compston A (2017) Henry Head: a life in science and society. J Neurol Neurosurg Psychiatry 88:716-717

2. Head H (1893) On the disturbances of sensation with special reference to the pain of visceral disease. Brain 16:1-163

3. Beissner F et al. (2011) Forgotten Features of Head Zones and Their Relation to Diagnostically Relevant Acupuncture Points. 2011: 240653 https://doi.org/10.1093/ecam/nen088

4. Hauser W (1970) The significance of viscero-cutaneous reflexes for the pathogenesis of dermatoses. In: HA Gotton and W. Schönfeld. Dermatologei und Veneroloogie, Supplementary volume, Georg Thieme Verlag Stuttgart pp.329-388
5. Putz, R (ed.): Sobotta, Atlas of human anatomy. Volume 2, 20th edition. Urban & Schwarzenberg, Munich 1993, p. 346.