of legs that serve as specialized jackknife claws. The tail carries numerous sharp spines that may project
beyond the edge of the sturdy tail fin. Lacerations may be induced by either the front raptorial (prey-
acquiring) claws or the tail, particularly when the shrimp attacks an unwary victim. It has been claimed that an
attacking mantis shrimp struck with enough force to crack a diver's facemask. In the Caribbean, the
stomatopod ("foot-mouth") mantis shrimp is known as "thumb splitter." Odontodactylus scyllarus from the
Indo-Pacific can be afflicted with a disease that digests areas of its dorsal cuticle and eventually is lethal. This
may explain one anecdotal report of a human finger wound (which led to amputation) characterized by
cartilage destruction and from which no pathogenic organism could be cultured. The mantis shrimp is a
superb predator, in part because it has the most highly developed eyes of any crustacean.
Triggerfish
The triggerfishes are usually shy and unimposing, but during mating season the females of at least two
species (Pseudobalistes fuscus and the "giant" Balistoides viridescens) can become extremely territorial in
guarding a nest and thus aggressive, inflicting painful bites. The former can grow to 55 cm and the latter to 75
cm. The strong jaws each carry eight long, protruding, and chisel-like teeth in an outer row, backed by an
inner row of six teeth. Usually the fish "bites and runs," but the orange-striped triggerfish Balistoides
undulatus has been reported to bite and not release. It is common to have to strike the fish in some manner to
get it to release. In the Gilbert Islands a release technique is to bite the fish on the top of the head.
Stony Corals
The anthozoan Madreporariae, or true (stony) corals, exist in colonies that possess calcareous outer
skeletons (the origin of calcium carbonate, or limestone) with pointed horns, razor-sharp edges, or both .
There are nearly one thousand species of corals. Corals live in waters at temperatures of 20
o
C (68
o
F) or
higher, generally at depths of up to 20 fathoms. A "coral head" is actually a colony of individual polyps. Rare
species have been noted at depths of more than 6000 fathoms. Certain coral species, such as Plexaura
hommomalla, are under investigation as sources of prostaglandins and other pharmaceutical precursors to treat
conditions as diverse as asthma, leukemia, and infections. Pieces of coral have been evaluated for use as bone
grafts.
Coral reefs are under pressure worldwide from climatic changes (e.g., El Niño), chemical poisons
(e.g., cyanide used for fishing), natural predators (e.g., crown-of-thorns sea star), and mechanical destruction
(e.g., ship anchors and explosives).
Snorkelers and divers, particularly photographers and spear fishermen, frequently handle or brush
against these living reefs, resulting in superficial cuts and abrasions on the extremities. Coral cuts are
probably the most common injuries sustained underwater. The initial reaction to a coral cut is stinging pain,
erythema, and pruritus, most commonly on the forearms, elbows, and knees. Divers without gloves frequently
receive cuts to the hands. A break in the skin may be surrounded within minutes by an erythematous wheal,
which fades over 1 to 2 hours. The red, raised welts and local pruritus are called coral poisoning. Low-grade
fever may be present and does not necessarily indicate an infection. With or without prompt treatment, the
wound may progress to cellulitis with ulceration and tissue sloughing. These wounds heal slowly (3 to 6
weeks) and result in prolonged morbidity. In an extreme case the victim develops cellulitis with lymphangitis,
reactive bursitis, local ulceration, and wound necrosis.
Coral cuts should be promptly and vigorously scrubbed with soap and water, then irrigated copiously
with a forceful stream of fresh water or normal saline to remove all foreign particles. Using hydrogen
peroxide to bubble out "coral dust" is occasionally helpful. Any fragments that remain can become embedded
and increase the risk for an indolent infection or foreign body granuloma. If stinging is a major symptom,
there may be an element of envenomation by nematocysts. A brief rinse with diluted acetic acid (vinegar),
papain solution, or isopropyl alcohol 20% may diminish the discomfort (after the initial pain from contact
with the open wound). If a coral-induced laceration is severe, it should be closed with adhesive strips rather
than sutures if possible; preferably it should be debrided for 3 to 4 consecutive days and closed in a delayed
fashion.
A number of approaches can be taken with regard to subsequent wound care. One method is to apply
twice-daily sterile wet-to-dry dressings, using saline or a dilute antiseptic (povidone-iodine 1% to 5%)
solution. Alternatively, a nontoxic topical antiseptic or antibiotic ointment (mupirocin, bacitracin or
polymyxin B- bacitracin-neomycin) may be used sparingly and covered with a nonadherent dressing (eg,
