but critical medical conditions that may present to an orthopedic surgeon and that can - if undiagnosed, misdiagnosed or left untreated - result in serious risk to life and limb. Since these conditions are not necessarily common in orthopedic settings, the goal is to promote pattern recognition through the use of a consistent chapter format beginning with illustrative cases for each condition, followed by an appropriate review of the literature, relevant questions, recommended diagnostic and clinical approaches, and bulleted pearls and pitfalls. Conditions presented include necrotizing fasciitis, epidural hematoma, popliteal entrapment syndrome, allergies, coagulations issues, lead toxicity, and much more. Radiographs and intraoperative photographs enhance the case material.