A Philadelphia collar is a hard cervical brace made of two pieces and used by orthopedic surgeons and emergency room doctors to fixate and stabilize the cervical spine following an injury, fracture, or surgery. It is composed of lightweight EVA foam with adjustable velcro straps, which allow it to keep the head still and provide maximum comfort during extended periods of wearing. Philadelphia collars are radiolucent, making them suitable for X-rays, CT scans, and MRIs.