The first X-ray picture taken was of which part of the human body?

At the end of the 19th century, while studying the effects of passing an electrical current through gases at low pressure, German physicist Wilhelm Röntgen accidentally discovered X-rays—highly energetic electromagnetic radiation capable of penetrating most solid objects. His discovery transformed medicine almost overnight. Within a year, the first radiology department opened in a Glasgow hospital, and the department head produced the first pictures of a kidney stone and a penny lodged in a child’s throat.

When Röntgen held a piece of lead in front of the electron-discharge tube, it blocked the rays, but he was shocked to see his own flesh glowing around his bones on the fluorescent screen behind his hand. He then placed photographic film between his hand and the screen and captured the world’s first X-ray image. Six weeks later, at the close of 1895, he published his observations and mailed his colleagues a photograph of the bones of his wife’s hand, showing her wedding ring on her fourth finger.