In older days, palms and fingers were scanned for identification. Now, palms and fingers with implanted sensors became scanners themselves. These implants come in different models, yet there are two main variations. First, a simple scanner for daily use: it helps to read different tags and product codes, and to exchange digital business cards via renewed handshake ritual (you still can use face recognition to identify a stranger but this is considered indecent; besides, many people use protection from face recognition - hats with special veils are popular). Another big class of palm/finger scanners are based on more profound implants for technicians and other professionals. For example, "doctor's hand” includes various medical sensors for diagnostics - even a portable endoscope with direct video stream to doctor’s visual cortex.