In the case of abdominal trauma in a child, which organ is MOST likely injured with a contusion in the left upper quadrant?

The spleen is the organ most likely to be injured when there is abdominal trauma, especially in the left upper quadrant. This is due to the spleen's anatomical position and its relatively fragile structure. In children, the spleen is more prone to injury during blunt trauma because of its size and the fact that it is surrounded by more protective structures in adults, such as the rib cage.

When a child experiences trauma in the left upper quadrant, such as from a fall or a vehicular accident, the spleen can be compressed against the ribs or other abdominal organs, leading to contusions or lacerations. Spleen injuries are particularly common in pediatric patients due to their high vascularity, meaning that even minor traumas can result in significant bleeding.

While other organs like the liver, kidney, and pancreas can also be injured in abdominal trauma, the liver is located in the right upper quadrant, making it less likely in this specific context. The kidney is located further back in the abdominal cavity, while the pancreas, though it can be injured, is anatomically positioned more towards the back and would not typically present with pain or symptoms that are as closely related to left upper quadrant trauma. Thus, the spleen is indeed the most likely