Most times, the mishaps for a distracted walker are minor, like the lightly dinged head and broken fingernail that Ms. Briggs suffered, a jammed digit or a sprained ankle, and, the befallen say, a nasty case of hurt pride. Of course, the injuries can sometimes be serious  and they are on the rise.

Slightly more than 1,000 pedestrians visited emergency rooms in 2008 because they got distracted and tripped, fell or ran into something while using a cellphone to talk or text. That was twice the number from 2007, which had nearly doubled from 2006, according to a study conducted by Ohio State University, which says it is the first to estimate such accidents.

“It’s the tip of the iceberg,” said Jack L. Nasar, a professor of city and regional planning at Ohio State, noting that the number of mishaps is probably much higher considering that most of the injuries are not severe enough to require a hospital visit. What is more, he said, texting is rising sharply and devices like the iPhone have thousands of new, engaging applications to preoccupy phone users.

Mr. Nasar supervised the statistical analysis, which was done by Derek Troyer, one of his graduate students. He looked at records of emergency room visits compiled by the Consumer Product Safety Commission.

Image Phones aren't just distracting drivers; they make pedestrians inattentive too. Credit... Richard Perry/The New York Times

Examples of such visits include a 16-year-old boy who walked into a telephone pole while texting and suffered a concussion; a 28-year-old man who tripped and fractured a finger on the hand gripping his cellphone; and a 68-year-old man who fell off the porch while talking on a cellphone, spraining a thumb and an ankle and causing dizziness.