MSK Individual Readiness Assurance Test (iRAT) Practice Test

When a dog cannot open its mouth, the first priority is to look for mechanical problems in the jaw and skull that would physically prevent opening. Imaging the skull with radiographs lets you visualize the mandible, temporomandibular joints, maxilla, and teeth to detect fractures, dislocations, severe dental disease, or osteomyelitis. These findings are common and treatable causes of trismus, and they guide the next steps in management. If the skull radiographs show no structural issue, you then investigate non-mechanical causes such as inflammatory or autoimmune muscle diseases, which would be pursued with specific tests like antibody titers. So skull radiographs are the best next test because they directly assess the most likely surgical or traumatic causes and quickly direct subsequent diagnostic decisions.