Do a lot of people get renal trauma?

Depends of Severity. The kidneys are generally well protected under the ribs and heavy flank muscles. However, major blows such as from motor vehicle accidents, falls from heights, large objects, fists, etc. May crush or compress the kidneys. Of course penetrating objects like knives, gunshots, or missiles, can directly damage any internal organ. Blood in the urine is often found after major kidney trauma.