Final answer:
The most common birth injury in newborns is a fracture of the clavicle.
Step-by-step explanation:
The most common birth injury in newborns is fracture of the clavicle. A fracture of the clavicle, or collarbone, can occur during delivery when there is difficulty in passing the baby's shoulders through the birth canal. This injury is more commonly seen in larger babies or when instrumental delivery techniques, such as forceps or vacuum extraction, are used. The fracture typically heals on its own within a few weeks with proper care and support.