Crotalids

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Centipede Bites

Hospital Corpsman Revised Edition

Signs and symptoms of snake bite

CROTALIDS.-Crotalids are of the Viperidae (viper) family and are called "pit vipers" because of the small, deep pits between the nostrils and the eyes (fig. 5-3). They have two long, hollow fangs. These fangs are normally folded against the roof of the mouth, but they can be extended when the snake strikes. Other identifying features of the Crotalids include thick bodies; slit-like pupils of the eyes; and flat, triangular heads. The most identifying feature of a pit viper is the relative width of the snake's head compared to the thickness of the body. The head will be much wider than the body, giving the appearance of an arrowhead. The difference in size is so obvious that identification of a snake as a pit viper can usually be made from a safe distance.

Further identification can be made by examining the wound for signs of fang entry in the bite pattern. Pit viper bites leave two puncture marks (sometimes only one, and sometimes more). Nonvenomous snakes (for example, garter snakes) leave a series, often in a curve or semi-circle, of tiny scratches or punctures. Individual identifying characteristics include rattles on the tails of most rattlesnakes, and the cotton-white interior of the mouths of moccasins.

ELAPIDS.-Coral snakes are of the family Elipidae and related to the cobra, kraits, and mamba snakes in other parts of the world (fig. 5-4). Corals, which are found in the Southeastern United States, are comparatively thin snakes with small bands of red, black, and yellow (or almost white). Some

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Figure 5-3.-American pit vipers.

nonpoisonous snakes have similar coloring, but in the North American coral snake, the red band always touches the yellow band, and the bands go all the way around the body. (In some of the nonvenomous, similarly colored varieties, the bands are only on the back and sides, not the belly.) There is an old saying that only applies to NORTH American coral snakes: "Red on yellow, kill a fellow; red on black, venom lack." The coral snake has short, hollow fangs that chew into its victim and introduce the poison. Coral snake venom is dangerous, so if the skin is broken, give antivenom before envenomation is evidenced by symptoms or findings.

Venom, which is stored in sacs in the snake's head, is introduced into a victim through hollow or grooved fangs. An important point to remember, however, is that a bitten patient has not necessarily received a dose of venom. The snake can control whether or not it will release the poison and how much it will inject. As a result, while symptoms in a poisonous snakebite incident may be severe, they may also be mild or not develop at all.