Chapter 24 Hunting and Fishing Injuries
Hunting is a popular pastime in the United States, and injuries are quite common. The instruments used to kill game are inherently dangerous, and hunters often place themselves in dangerous situations, such as tree stands, to improve their success. Understanding wound ballistics, types of firearms, arrows, and traps can aid the clinician in caring for the various wounds produced by these instruments. Fishing has specific injuries as a result of hooks and spears, and the clinician should know various techniques for their removal.
Anthropologists have many theories concerning the origins and importance of hunting in the evolution of the human species. The physical attributes of bipedal locomotion, binocular vision, and an opposable thumb all make humans more efficient hunters. Whether these exist because humans have an innate compulsion to hunt or whether humans are hunters because of these traits is debatable. There is no debate, however, that human social evolution, language, the use of tools, and domestication of animals are directly related to more efficient hunting. In a survival situation, and in some ways with regard to evolution, hunter–gatherer animals have a distinct advantage over strictly vegetarian animals because of the relative food value of meat over plants. Hunters tend to be males. Approximately three-fourths of all calories in modern hunter–gatherer groups are derived from plants, and this portion of the food is usually supplied by the women in the group. Even in Inuit tribes where plants make up little of the diet, women do most of the fishing while the men hunt.
Hominids were at a disadvantage, even in groups, when hunting large animals or driving off other predators from their kills until they began using stones, long bones, and sticks to enhance their relatively weak teeth and claws. Implements for hunting and skinning animals were the earliest tools found by anthropologists. Human cultural evolution followed closely the technologic changes in weapons, although sports, business, and war had replaced the need for hunting in most cultures, even by the time Nimrod walked the earth. Bows and arrows, slings, spear throwers, nets, harpoons, traps, and firearms were designed to extend the reach and increase the lethality of the human hand. Unfortunately, humans discovered that they could kill each other with these weapons. Since the discovery of gunpowder, the development of weapons technology has surpassed all other forms of human endeavor, including medicine and transportation.4,5,14
Only a few cultures still depend on hunting as their primary food-gathering method. Examples are the Mbuti tribe of the Ituri Forest in Zaire, Andaman Islanders in the Bay of Bengal, and the Inuit. Many cultures use hunting to supplement agriculture, plant gathering, or raising livestock. Most hunting in the United States is done for sport or pleasure, although in some areas of the country, hunting and trapping are still the primary source of income for a few people.
The total number of hunters and trappers is unknown. Some participate illegally and are not licensed. In 2006, throughout the United States, 12.5 million individuals purchased hunting licenses, and hunting expenditures totaled $22.9 billion. Although hunting seasons are regulated and relatively short, hunters spent 16 million visitor-days in the national forests and 220 million days total. Fishing numbers for 2006 show 30 million anglers and $42.2 billion in expenditures.
The North American Association of Hunter Safety Coordinators (NAAHSC), a division of the New York State Office of Wildlife Management, reported 860 fatal hunting injuries in the United States during the 4-year period between 1983 and 1986, with a total of 6992 injuries from firearms.44 Interestingly, 34% of the total injuries and 89% of the handgun injuries were self-inflicted. Shotguns accounted for 106 of the fatalities and 906 of the total injuries, whereas rifles accounted for 79 fatalities and 465 injuries. The New York State Department of Environmental Conservation reported that the average number of hunting injuries decreased from an average of 137 per year in the decade of the 1960s to only 48 in 2001 and 37 in 2002.8 They credit the institution of hunter safety programs in 1960. In 2001 Colorado reported 9 injuries and 1 death per 500,000 licensed hunters.11 Michigan reported 2 deaths per 2,665,952 hunters in 2003, giving hunting one of the lowest injury and fatality rates of any recreational activity.57
The type of hunting also influences the rate of injury. Smith and colleagues51 reviewed 1345 hunting injuries in Pennsylvania from 1987 to 1999. They showed that turkey hunters had the highest rate of injury (7.5 per 100,000 hunters) and grouse hunters the lowest (1.9 per 100,000 hunters). This was attributed to turkey hunters not wearing orange hunter clothing. Deer hunters had the highest case-fatality ratio at 10.3%, and pheasant hunters the lowest at 1.3%. This higher fatality rate was largely because most deer-hunting injuries were due to wounds caused by rifle bullets. They also noted that younger hunters suffered the highest rate of injuries, and the largest percentage of incidents occurred on opening day.
Hunting-related shootings represent a very small portion of the total number of accidental firearm deaths in the United States. In Colorado, from 1997 to 2005, there were four deaths during hunting, all attributed to cardiac causes, and none in hunters from firearms, falls, or penetrating injuries. The most common traumatic injuries were lacerations; 75% of lacerations were from knife injuries while field dressing the animals. Of 131 unintentional firearm deaths in California from 1977 to 1983, only 8 were the result of hunting accidents.*
Hunting injury data may be inaccurate for a number of reasons. Many minor nonfatal injuries may go unreported, and most states do not differentiate accidental firearm hunting deaths from deaths that occur during any other activity. Also, automobile and all-terrain vehicle accidents that occur while hunting, or gunshot wounds inflicted while “cleaning a gun” at home, may be classified as hunting or nonhunting injuries.
Most injuries to hunters are the same types of injuries seen in backpackers, fishermen, and climbers. Frostbite, sprains, burns, and fractures occur with the same frequency in hunters as in others who visit wilderness areas. Prolonged extraction times may increase the risks of hypothermia, wound infection, dehydration, missed medications, and other time-dependent secondary complications.
Injuries that are unique to hunters are those caused by their weapons. Most hunting is done with firearms. Shotguns and rifles are more commonly used, although handguns are increasing in popularity. Use of bows and crossbows in hunting is also rapidly increasing. Hunters using these weapons frequently are permitted an extended hunting season that does not overlap with periods for rifle and shotgun hunting. Hunters who use bows and crossbows pose far less danger to people in the hunting area at long range compared with those using rifles and shotguns. Bow hunting requires more skill, use of camouflage, and stealth because of the short effective ranges of arrows and bolts. These factors place bow hunters at greater risk for being mistaken for a game animal at long ranges, which is why rifle and shotgun seasons rarely run concurrently with bow-hunting activity.
Other weapons used for hunting are less likely to be encountered. For example, spears, harpoons, and nets are used by some hunters in the Arctic, Australia, and Africa. Spear injuries from gas-powered spearguns or rubber band–powered Hawaiian slings have been associated with fatal injuries, especially when occurring in ocean or lake environments where secondary drowning or shark attack may be an additional hazard. Harpoon and fishing spearheads may separate from the shaft and, depending on the force used, may penetrate the skull or a body cavity. Slingshots are rubber band–powered devices that use the energy in a stretched piece of rubber to hurl a projectile, often a small rock or ball bearing, at 61 to 91 m/sec (200 to 300 ft/sec). Although this is considered a low-velocity and thus low-energy projectile, injuries to the head and face, especially the eyes, have been reported.
Blowguns, although mainly used by aboriginal hunters, have become popular with some recreational hunters of birds and small game. The blowgun varies in length, and a variety of darts can be projected 6 to 15 m (19.7 to 49.2 feet) by the exhaled breath. The darts have low energy and do not penetrate very deeply. Modern blowguns rarely cause serious injury unless striking the eye or possibly a blood vessel. To effectively kill small game, the darts generally must carry an immobilizing or poisonous toxin. Darts used by some tribes contain toxins derived from both animal and plant sources. These toxins can cause paralysis and death in humans who have been punctured by the dart either accidently during transport or purposefully during tribal war. Animal toxins are primarily neuromuscular toxins and many have been developed for medical use. South American tribes have used Dendrobates frog toxins, which are steroidal alkaloid compounds known as batrachotoxins and homobatrachotoxins. These toxins act at voltage-gated sodium channels and cause irreversible depolarization of nerves and muscles. Several other toxins, including gephyrotoxin, pumiliotoxins, histrionicotoxins, and epibatidine, have been isolated from poison dart frogs. The last toxin is the most potent nicotinic agonist known and is a powerful nonopiate analgesic. Interestingly, these frogs lose their ability to produce toxins in captivity, leading to the finding that the frog’s diet of Melyridae beetles actually is the source of the toxins. Plant-derived toxins include strychnine, curare, and a number of cardiac glycosides from Africa, South America, and Asia, where dart and arrow poisons are still used by indigenous people. All of these toxins, especially the cardenolides from the Maquira, Naucleopsis and other Moraceae species, have been studied for possible medicinal value.46,49
Veterinarians commonly use air-powered darts fired from rifles or blowguns to subdue large animals. These darts contain pharmacoactive agents, such as succinylcholine, phencyclidine, ketamine, and xylazine, in concentrations great enough to bring down an elephant, lion, or rhinoceros. The darts are 3-mL plastic syringes with 16-gauge needles delivered using a 1.8-m (5.9-foot) blowgun or rifle. Accidental human injection can be rapidly fatal if reversing agents or advanced life support is not available. Homemade blowguns are frequently used for sport and usually consist of a needle or pin attached to a wooden shaft and a cotton ball or piece of yarn for a feather. Although these darts do not contain any toxins, they are still capable of causing injuries, especially to the eye. There have been reported cases of aspiration of darts.27,29,59
Trap injuries may be included in the definition of hunting injuries. Most traps are designed to catch and hold small game. Injuries usually occur when a trapper triggers a spring-loaded trap prematurely. Crush injuries and puncture wounds to the hands are most common. Hikers occasionally tread on unmarked traps, and domestic animals such as dogs are accidentally caught in poachers’ traps. Another problem with traps occurs when an animal (wild or domestic) is caught in a trap and attacks the trapper while being released.
Many knife lacerations occur when hunters clean game. Lack of familiarity with the process or techniques for field dressing and cleaning game is the likely cause. Failing to wear protective gloves; using the wrong type of knife; working with bloody, slippery material; and having cold hands all contribute to accidents.
A frequent preventable cause of serious injury and death among hunters is not associated with firearms at all. It is the tree stand injury. Tree stands are small platforms designed to hold hunters high above the ground so they can more easily spot and kill large game while remaining undetected. Whether homemade or of commercial design, the platforms generally are small, portable devices that the hunter attaches to the trunk of a tree near game trails or water holes. The stands may have attached ropes or ladders for access, or the hunter may free-climb the tree for placement of the stand or fasten small climbing steps on the tree (Figures 24-1 and 24-2). Hunters may fall asleep on the platforms and fall off or fall while climbing up or down trees. At least one-half of these injuries could be prevented if all hunters wore tree stand safety harnesses (Figure 24-3). Although most of the injuries are similar to those seen with any type of fall, occasionally a hunter drops a firearm, which discharges, or falls on an arrow or rifle, causing an additional weapons injury. Over 10 years, injuries of this type in Georgia accounted for 36% of reported hunting injuries and 20% of hunting fatalities.7 A study from the University of Rochester, New York, looked at tree stand injuries from 1996 to 2001.47 The authors noted that 51 injuries occurred, all in men, with a mean age of 42. Alcohol was present in 10% of patients and 2 of 3 deaths. Spinal fractures were the most common injuries (51%), followed by extremity (41%), head (24%), and lung injuries (22%). Only two patients had been using a safety belt (4%). Sixteen spinal cord injuries were reported between 1987 and 1999 in Oklahoma; the mean height of fall was 16 feet, and 18% were related to alcohol ingestion. Ninety percent resulted in paraplegia/paraparesis, and 12.5% were fatal.*
Modern arrows are usually made from aluminum, graphite, or fiberglass, although many beginners still use inexpensive wooden arrows. A number of types of arrowhead are in use, such as field points and target points, but most injuries are due to specially designed hunting arrowheads called broadheads. These razor-sharp metal points come in a variety of sizes and shapes and are designed to kill game by lacerating tissue and blood vessels, causing bleeding and shock. Unlike hunting firearms projectiles, which are designed to kill quickly through massive tissue damage and rapid incapacitating hemorrhage, arrows usually kill more slowly with less tissue damage (Figure 24-4).3,22,23,25Arrows are propelled by a conventional bow, which may be straight, recurved, or compound, or by a crossbow. Crossbow projectiles may be called arrows or bolts and generally are shorter and heavier than arrows fired from a bow. The force used to propel the arrow is usually measured in draw weight, which is the number of foot-pounds necessary to draw a 71.1-cm (28-inch) arrow to its full length. The higher the pound draw, the more powerful the bow and the deeper the penetration acheived by the same type of arrow.
FIGURE 24-4 Types of arrows. Top, Aluminum shaft arrow with hunting broadhead. Middle left to right, Small game blunt hunting head with spring claws to prevent arrow loss from burrowing into the ground, two types of hunting broadheads, four field points of varying weights. Bottom, Fiberglass shaft for interchangeable heads.
Arrows have a much shorter range than do bullets, and arrows must be more accurately placed to kill the animal quickly; therefore most shots taken are under 50 m (164 feet). Because brush and tree branches can easily deflect an arrow, most shots are taken with a clear field of view. For these reasons, bow hunters rarely mistakenly shoot another hunter they presumed was a game animal. Most arrow injuries occur when hunters fire illegally at night in heavy brush and are not sure of their target. Another common injury occurs when a hunter runs after a wounded animal and falls on an arrow that was to be used for a second shot or falls out of a tree stand onto an arrow. A loaded crossbow is similar to a loaded gun. Hunters have been accidentally shot when dropping the weapon or snagging the trigger on a branch or fence. Hunting arrowheads are quite sharp; self-inflicted injuries may occur when a hunter is sharpening the blades of the broadhead or returning an arrow to the quiver.
Although the word firearms technically defines guns that fire projectiles by ignition and burning of a propellant, similar designs referred to as “nonpowder” firearms using springs, compressed air, or compressed gas cartridges are in widespread use among sportsmen and children and will be considered as firearms in practical use.
Whereas traditional firearms discharge a projectile by the contained expanding gases generated in the gun barrel by modern fast-burning powders or old-fashioned black powder, nonpowder firearms use a spring, compressed air, or carbon dioxide cartridge to accelerate the projectile out of the barrel. Although air guns are quite accurate at short distances and can develop muzzle velocities in excess of 365.8 m/sec (1200 ft/sec), the small lightweight projectiles usually cannot penetrate skin at distances greater than 100 m (328 feet). Nonpowder firearms are commonly used by children, who cannot legally obtain or use other types of firearms. Uninformed parents buy them as toys, erroneously believing them to be harmless by design. Without supervision and proper training in gun safety, severe injury and death can result. The wounds they cause can be lethal, especially from high-powered air rifles, which can send out pointed projectiles at sufficiently high velocities to penetrate the skull and body cavities. In a recent technical report, Laraque and colleagues estimated 21,840 injuries during the year 2000 from nonpowder firearms, with a 4% hospitalization rate. There were 39 resultant deaths between 1990 and 2000. Care must be taken not to trivialize these injuries, especially in the pediatric patient, where softer, thinner bone may lead to deep penetration by even lightweight projectiles.* Less than lethal (LTL) rounds are used by police and military to subdue individuals without causing serious injury. These rounds may be rubber, wooden, synthetic sponge, or soft wax. Although designed to disperse a crowd or incapacitate a person until he or she can be subdued, they can cause significant injury. This usually occurs when the person is struck in the head or in some cases the abdomen or thorax. These rounds are not designed for hunting but may be encountered if used by the uninitiated. Rounds such as airsoft are used in many police and military training facilities to add realism to the training scenario. These rounds may cause eye injuries if safety precautions are not used.21,31 Paintball guns, although not designed or generally used for hunting, are commonly used in outdoor activities that mimic tactical games. Most injuries occur in children who are not wearing eye protection, but there are also reported cases of vascular injuries. Paintballs are 14-mm (0.6-inch) gelatin capsules that are filled with water-soluble paint of various colors. Because of their small size, they can bypass the bony orbital protection of the eye. Paintballs propelled by carbon dioxide can travel over 91.4 m/sec (300 ft/sec). At this velocity, the globe, cornea, and retina can be disrupted with a direct hit. The American Society for Testing and Materials has standards for eye protection for paintball sports. These include a helmet with integral eye, face, and ear protection (Figure 24-5). Unfortunately, many children either do not wear the recommended protection or remove it during play because of fogging or discomfort.12,24,28,30,38
Black powder weapons use a centuries-old slow-burning propellant that is ignited with a spark from flint striking steel or a percussion cap. The firearms are usually single shot and loaded from the muzzle by pouring a measured amount of black powder down the barrel and then inserting the projectile and tamping it down onto the powder charge. When ignited, the propellant is converted to a gas that expands and pushes the projectile out of the barrel of the weapon. With modern design and manufacturing techniques, these weapons are sufficiently accurate to hunt large game, such as deer and elk. The injuries from black powder weapons are similar to those from modern weapons and are discussed later. The same precautions should be used when hunting with or shooting any type of firearm, whether the propellant is air or gunpowder.1,2,13,45
The term cartridge is used to refer to the intact, unfired assembly of projectile and propellant loaded into the gun for firing. Rifle and pistol cartridges consist of a metal case that contains the gunpowder propellant and into which the bullet is seated and held by compressing the case around the bullet base at the time of manufacture. The base of the case contains a small metal primer filled with a small amount of high explosive that serves to ignite the fast-burning propellant when it is struck by the firing pin of the gun. The primer is in the center of the base of the case (center-fire ammunition) in all cartridges except in small-caliber .22 cartridges, where it is incorporated into the entire circumference of the cartridge base rim (known as rimfire ammunition). Rifle and pistol cartridges generally contain a single bullet, although some may be loaded with very small shot to increase the probability of hitting small objects at short distances. Shotgun cartridges consist of a center-fire metal base combined with a paper or plastic shell in the form of a closed-end tube. Within this tube is placed the propellant and then the projectile(s), along with associated plastic, cotton, or paper materials collectively referred to as wadding (Figure 24-6).
Shotgun projectiles consist of shot ranging in size from 1 to 10 mm (0.04 to 0.4 inch) (Figure 24-7) or a single solid projectile known as a slug. Shot pellets used to be made of lead. Because of high lead levels in ducks and geese that ingested spent shot while feeding, lead shot for bird hunting was banned in 1991. Approved shot may be made of steel, tin, or various mixtures of tin, bismuth, and up to 15% iron. Steel shot can be identified on radiographs because it retains a perfect round shape, whereas lead and tin shot deforms inside the barrel during firing, resulting in nonspherical shapes. Determining the shot type can help clinicians decide about the safety and usefulness of magnetic resonance imaging scans in the setting of steel projectiles, or the risk for lead toxicity.
FIGURE 24-7 Standard shot size number and letter system (with corresponding metric measurements) of hunting shotgun shell projectiles. The smaller the shot size, the more pellets loaded in a single shotgun shell. Larger pellets are heavier, lose less velocity per unit of flight time, and penetrate more deeply than do smaller pellets.
(From Shotgunworld.com. Used with permission.)
The wadding is commonly a single plastic cup with a thickened expandable base designed to contain the shot and serve as a seal inside the barrel to contain the expanding gases behind the shot cup for maximal muzzle velocity. Slugs also have a type of wadding known as a sabot, which surrounds the slug inside the barrel of the shotgun. In all cases, the wadding is fired from the gun and immediately peels away from the slug or shot. Wadding is commonly found inside close-range wound channels but generally is not involved in wounds at firing distances of more than 5 to 7 m (16 to 23 feet).
Beside the wadding and projectile(s), hot gas and unburned powder also exit the muzzle. In cases of close-proximity wounds, usually under 1.1 m (3.5 feet), powder stippling may appear on clothing or skin. The presence of powder stippling or wadding in a wound may have important forensic applications and should always be noted. With contact wounds, where the muzzle is pressed into the skin at the time of firing, escaping hot gases may enter the wound channel and expand inside the victim, causing burns, organ damage, burst skin, and/or a stellate laceration around the point of entrance. Figures 24-8 to 24-10 show examples of gunshot wounds.