Fig. 1.

Negative clinical examination and FAST in high mechanism injury: 40 year old with major extremity injury following high mechanism blunt trauma was diagnosed fast negative in ED and had no obvious abdominal complaints at presentation. WBCT (Figure a) at the same time showed small mesenteric hematoma (arrow head) in left iliac fossa surrounded by large area of mesenteric fat stranding. FAST was negative since there was no hemoperitoneum as confirmed by WBCT. Initially this was not addressed since patient had no abdominal complaints nor guarding on clinical examination. Two days later patient complained of abdominal pain and developed distension as well as guarding on clinical examination. Repeat CT scan (Figure b, c) shows large pneumoperitoneum (star) and increase in mesenteric collection with air pockets (arrow) suggesting ruptured bowel due to mesenteric injury.