Final answer:
A patient with blunt trauma holding the lateral side of his chest with rapid and shallow respirations most likely has a rib fracture, although medical evaluation is needed to rule out other conditions like a pneumothorax.The correct option is 3.
Step-by-step explanation:
A patient with blunt trauma who is holding the lateral side of his chest and has rapid and shallow respirations is most likely suffering from a rib fracture. The symptoms described are typical indicators of a rib fracture, which includes pain on the side of the injury, difficulty in breathing deeply due to pain, and the protective holding of the injured area. While other conditions like pneumothorax, pulmonary embolism, and cardiac contusion can also present with chest pain and respiratory issues, the specific details of holding the lateral side and the mode of injury suggest a rib fracture. It is important, however, that the patient receives a full medical evaluation to rule out or treat other injuries, such as pneumothorax, which can occur concurrently with a rib fracture and may not be immediately obvious.