The itch-scratch relationship is said to be one of the human body's great biological mysteries.

Now, scientists have claimed that itch is felt most intensely at the ankle which is also the best place to scratch. A new study by Liverpool John Moores University says that ankle is the most satisfying spot to scratch and it even beats hard-to-reach parts of the back, the latest issue of 'British Journal of Dermatology' reported.

For the study, the scientists recruited some healthy male and female volunteers, aged 22 to 59. The subjects were made to itch by rubbing them with cowhage, a plant with tiny hairs that irritate the skin.

The itches were induced on three parts of the body - forearm, ankle and back. For five minutes, participants were asked not to scratch, instead told to record how itchy they felt at each spot, 'The Sunday Telegraph' reported.

Then the scientists scratched each location themselves with a laboratory brush and asked the volunteers exactly how pleasurable the sensation was.

On comparison of the sensation of scratching on different areas of the skin in the three parts of the body, the findings revealed that the itch was felt most intensely at the ankle.

And, ankle was also the spot where pleasure of scratching was felt most keenly and persisted longest, say the scientists. By contrast, the forearm was the least itchy spot, and scratching there produced pleasure that was briefer and lower in intensity.