Which of the following poses the greatest airway risk?

The plunging ranula poses the greatest airway risk primarily due to its potential to grow in size and posteriorly displace the tongue and other soft tissues, leading to airway obstruction. A plunging ranula originates from a sublingual gland or duct and can accumulate mucus or fluid that causes swelling. As the lesion expands, it can push against the base of the tongue, increasing the chance of obstructing the airway, particularly in cases where airway management is already complicated, such as in patients with limited airway control or in emergencies.

In contrast, while other conditions such as submandibular gland swelling and mandibular fractures can impact airway management, they may not exert the same immediate and significant displacement of airway structures as a larger or more aggressive plunging ranula. The retromolar trigone lesion, while potentially serious, doesn’t typically cause the same risk of obstructive airway compromise unless associated with widespread disease or secondary complications. Therefore, in terms of immediate airway risk, a plunging ranula can pose a more acute threat compared to the other options.