Review Question - QID 219296

A 6-year-old boy presents to the clinic with left hip pain following soccer practice. His parents deny any trauma, only that he suddenly fell to the ground while running. Physical exam is notable for pain with axial load and log roll. Sensation and perfusion are intact distally. Preoperative radiographs and CT are shown in Figure A. He undergoes aspiration and bone grafting of the lesion, which reveals abundant yellow serous fluid. He then undergoes open reduction internal fixation of the proximal femur, shown in Figure B. Which of the following is the most common location for these lesions?