Sir.—To our knowledge, primary infection of the obturator internus muscle (OIM) has not been previously reported. The following patient report illustrates the diagnostic challenge posed by this unusual entity and outlines the clinical and radiologic features of this condition. A brief literature review of OIM abscess and psoas abscess is also presented.
—An 11-year-old Native American boy presented to our pediatric emergency department with a 1-week history of fever and right thigh pain that occurred shortly after an episode of strenuous exercise in the absence of any trauma. The pain was localized to the back of his thigh, and within 1 day, prevented him from bearing weight on his right leg. The following day he developed a persistent fever. He had previously been in excellent health with no unusual infections.Physical examination revealed a child without toxic symptoms with excruciating pain in the right buttock and posterior