Observations and results
Were your fingertips more sensitive than your arm? Why do you think one area is more sensitive than another?
The part of your brain that receives information from your sensory neurons doesn't treat all parts of the body equally. The reason you are more sensitive on your fingertips than your elbow is that there are many more sensory neurons on your fingertips. When an area has more sensory neurons there is a larger brain area devoted to receiving their signals, meaning more sensitivity. Most people find that their hands are much more sensitive than their backs or legs. Given how much you use your fingers for, that extra sensitivity makes good sense. You might even say it's handy!
More to explore:
People Hear with Their Skin, as well as Their Ears from Scientific American
Worlds of Feeling from Scientific American MIND
Touch and Pain from BrainFacts.org
Our Sense of Touch from the University of Washington in Seattle
How sensitive are you? from Your amazing brain.org