 This is a classic example of a patient that presents with pain, fever, difficulty swallowing, and a lot of jaw pain and has a rip-roaring infection. When we look at the contrast-enhanced CT scan, what we see is diffuse edema and phlegmon involving the right side of the floor of the mouth that's extending into the submandibular space with thickening of this muscle, which is the platysma muscle, and also reticulation of the subcutaneous fat. Now the majority of this phlegmon and inflammatory process is located within the floor of the mouth. So we talked early about the floor of the mouth being a compartment. The lateral aspect of the floor of the mouth is formed by the mandible. You have this muscle right here, which is the mylohyoid muscle that eventually connects with the hyoid bone, and we have the mylohyoid muscle going to the opposite side. When we have a diffuse inflammation involving the floor of the mouth, this is what's referred to as Ludwig's angina. So we call this a diffuse inflammation, but Ludwig's angina was initially described back in 1836 by a German physician by the name of Wilhelm Fredwig von Ludwig. So number one, Ludwig's angina was around long before CTs and MR was, and it is a clinical diagnosis. When we think of Ludwig's angina, we think of abscesses in the floor of the mouth that need to be drained. But the true Ludwig's angina is a diffuse cellulitis and phlegmon involving the floor of the mouth that essentially results in a compartment syndrome, because the mandible is solid, the mylohyoid is a very tough and firm muscle, and the hyoid bone is solid. So if we have a large infection that's involving the floor of the mouth, then this can result in elevation of the tongue base, and what's behind the tongue base? Well, the airways behind the tongue base, and this narrows the airway. The infection can extend down inferiorly to involve the pre-epiglottic space and the epiglottis. This is diffuse edema involving the epiglottis, and we can see it's narrowing the airway. So the term angina was initially described years ago, and I think initially by Dr. Ludwig, and it means strangulation. And the reason that patients with Ludwig's angina would present with strangulation is because they would have this diffuse inflammation involving the floor of the mouth. It would elevate the tongue base because of the firm floor of mouth soft tissues. It would narrow the airway, and that would give the patient the sensation of difficulty breathing. So in actuality, angina was initially described by us, the head and neck radiologist, and like many of the things in radiology, the term was stolen by the cardiologist.