Primary impact injuries commonly affects which of the following regions?

Primary impact injuries are due to the first pa struck by the vehicle. As to which pa of the body has been involved in the injury will depend upon the relation between position of the patient and the vehicle at the time the victim was being struck. The most commonly involved region are the legs irrespective of whether the primary impact is from behind or from the front, though it is more typical from the front. Head is most commonly injured in secondary injuries. Both chest and abdomen are involved in impact injuries especially when the person was facing the vehicle. Ref: The Essentials of Forensic Medicine and Toxicology By Dr. K. S. Narayan Reddy, 27th Edition, Pages 244-247; Forensic Pathology Reviews By Michael Tsokos, Volume 5, Pages 28-29.