Dewlap Dewlap A dewlap is a longitudinal flap of skin that hangs beneath the lower jaw or neck of many vertebrates. While the term is usually used in this specific context, it can also be used to include other structures occurring in the same body area with a similar aspect, such as those caused by a double chin or the submandibular vocal sac of a frog. In a more general manner, the term refers to any pendulous mass of skin, such as a fold of loose skin on an elderly person's neck, or the wattle of a bird. Dewlaps can be
Dennie–Morgan fold in these. The pathophysiology of this sign is not clear. One proposed mechanism is that continuous spasm of the superior tarsal muscle and skin edema could be due to hypoxia from poor circulation. A Dennie–Morgan fold should not be confused with an "allergic shiner", a purple-gray discolouration beneath the lower eyelid. This is related to the accumulation of blood and other fluid in the infraorbital groove resulting from nasal congestion. Dennie–Morgan fold A Dennie–Morgan fold, also known as a Dennie–Morgan line or an infraorbital fold, is a fold or line in the skin below the lower eyelid. It can simply