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 colleagues ⁵¹ 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 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.

Types of Injuries Encountered

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.

Tree Stand Injuries

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.*

FIGURE 24-1 The wrong way to use a tree stand. This hunter is not wearing a safety harness, is drinking alcohol, and is pulling his firearm into the tree stand with the muzzle pointing upward.

FIGURE 24-2 A commercially produced tree stand can be used to climb the tree and obviates the need for a ladder or steps, which are the cause of many falls.

FIGURE 24-3 The correct way to bring a firearm or quiver into the tree stand, with the muzzle or arrowheads pointing down and the hunter wearing a safety harness at all times.

Arrow Injuries

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.

Injuries From Firearms

Nonpowder Firearms

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

FIGURE 24-5 American Society for Testing and Materials–approved helmet designed for paintball activities with integral eye, face, and ear protection.

Powder Firearms

In older style weapons (black powder weapons), gunpowder is loaded directly into the barrel. In modern weapons, gunpowder is contained in a cartridge.

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).

FIGURE 24-6 Cutaway diagram of shotgun shell.

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.

FIGURE 24-8 Gunshot wound to the face and mandible showing extensive bone and soft tissue injury. Patient was initially able to protect his airway, but later required endotracheal intubation because of edema and bleeding.

FIGURE 24-9 Shotgun wound to the upper arm. Initially the wound looked benign. Both entrance and exit can be seen.

FIGURE 24-10 Radiograph of the same shotgun wound to the upper arm as seen in Figure 24-9. Extensive bone and soft tissue injury, as well as vascular and nerve damage, can be seen.

Hundreds of types of cartridges are available for firearms. They may be factory loaded or hand loaded, which adds the variables of propellant amount and type. Rifle and pistol cartridges are initially classified according to caliber, or diameter, of the bullet. For example, .22 caliber means the diameter of the bullet is 0.22 inch (5.6 mm); .45 caliber is 0.45 inch (11.4 mm); and so forth. The caliber may be expressed in metric measurement; for example, a 9-mm bullet is 9 mm in diameter, which is 0.35 inch. However, bullet diameter alone is insufficient to name a cartridge, because bullet length can vary, as do cartridge length and width. The U.S. Army M-16 service rifle fires a .22 caliber bullet weighing 4 g (62 grains) at 945 m/sec (3100 ft/sec) initial velocity. The common .22 rimfire rifle used by generations of young shooters fires a .22-caliber bullet weighing 2.6 g (40 grains) at 335.3 m/sec (1100 ft/sec) initial velocity. Obviously the wounding potential of these two projectiles is vastly different. Nomenclature for a particular cartridge is made more specific by including a measurement of cartridge length, name of the inventor or inventing company, amount of powder in the case, length of the entire cartridge, or the year the cartridge was invented. For instance, the M-16 round is generally referred to as a 5.56 mm (metric) or a .223 cartridge (English system of measurement), with the third digit differentiating it from the common low-power .22 rimfire cartridge. Other common hunting cartridge names illustrating these variations are .45/70 (70 grains of powder), .30-06 (adopted in 1906), and .35 Whelen (the man who developed the round).

Magnum refers more to the type and amount of powder than to the size of the bullet used. Magnum cartridges are designed to give hunters the ability to successfully hunt large game with pistols by improving terminal ballistic performance of the bullet. Figure 24-11 shows some examples of different bullets. Shotgun terminology is a little less complicated, based on the number of lead balls, the diameter of the barrel, and how many lead balls it takes to make a pound. For example, a 12-gauge shotgun has a barrel that is the same diameter as a lead ball that weighs 0.08 lb (37.6 g); a 20-gauge, 0.05 lb (22.7 g). The higher the gauge number, the smaller the barrel and the smaller the projectile. The only exception is the .410 shotgun, which is caliber .410, or 0.410 inch (1 cm) in diameter. Figure 24-12 shows some examples of shotgun rounds and the shot and wadding within them.

FIGURE 24-11 Examples of hunting bullets. Left to right, .50 caliber black powder lead bullet, .22 caliber long rifle lead bullet, .22 magnum caliber copper jacketed bullet, .44 magnum semijacketed hollow-point bullet, .44 magnum shotshell, .223 caliber (5.56 mm) full metal jacket bullet, .30/30 caliber soft point flat nose bullet, .30-06 caliber round nose soft point bullet, and .270 caliber pointed soft nose bullet.

FIGURE 24-12 Examples of shotgun rounds. Left to right, 12-gauge slug round, empty 12-gauge plastic round, plastic 12-gauge wadding, and No. 6 shotgun pellets.

The type and severity of wounds inflicted by a firearm depend on several factors. The most often quoted factor, but the least important, is the amount of energy the bullet (projectile) has when leaving the firearm. The kinetic energy formula, E_k = MV², can be applied to any moving object and can be used to calculate the muzzle energy for a particular type of firearm. Energy increases much more as a function of the velocity of the bullet than as a function of the mass. For this reason, most firearms are classified according to muzzle velocity. The higher the velocity of the bullet, the greater the energy and the greater the potential for injury. Firearms with muzzle velocities greater than 762 m/sec (2500 ft/sec) are considered high velocity, 457.2 to 762 m/sec (1500 to 2500 ft/sec) are medium velocity, and less than 457.2 m/sec (1500 ft/sec) are low velocity (Table 24-1).

TABLE 24-1 Comparison of Bullet Caliber, Weight, Velocity, and Muzzle Energy

Bullets cause damage to tissue by crushing. The energy of a bullet may be transmitted to the tissue in part or in total depending on the surface area the bullet presents to the tissue. Bullets that yaw, expand, or fragment present more surface area than do bullets that stay in one axis and maintain one shape. By international agreement codified in the articles of the Hague Convention IV of 1907, military bullets are not to be designed in a manner to produce “superfluous” wounding effects by features that would encourage the bullets to flatten or expand on impact with tissue. They are typically completely encased in a copper jacket to prevent deformation of the soft lead core. Such rounds generally pass through an individual, leaving a permanent wound tract similar in diameter to that of the bullet. The ammunition is designed to wound a soldier and put him or her out of combat, but not to kill the soldier. In contrast, hunting ammunition is designed to expand on impact up to two or three times its diameter, resulting in a much larger wound channel, greater tissue damage, and rapid incapacitation and death (Figure 24-13). This feature of planned deformation also promotes retention of the bullet within the target and reduces the risk for injury to unseen individuals downrange from the game animal. In fact, many states require the use of expanding ammunition for hunting large game. This may increase the wound severity of hunting injuries compared with military and criminal shootings.

FIGURE 24-13 The .30-caliber Nosler 180 g AccuBond Polymer Tip bullet fired into calibrated 10% ordnance gelatin is typical of the .30-caliber hunting bullets used for .30-06, .308, .300 Win Mag, and other cartridges. This photo shows this bullet fired from a .308 rifle with an 45.8 cm- (18-inch) long barrel. Muzzle velocity was 762 m/sec (2499 ft/sec). Penetration depth exceeded 50.8 cm (20 inches). Temporary cavity maximum width was 11.4 cm (4.7 inches) at a depth between 7.1 cm (2.8 inches) and 22.1 cm (8.7 inches). Diameter of the recovered bullet at the front surface was 1.4 cm (0.6 inches). Weight of the recovered bullet was 149.5 g (5.3 oz); 17% of the bullet turned into fragments. Terminal performance of this type is suitable for all medium to heavy game encountered in the lower 48 U.S. states, including moose, elk, black bear, pigs, and deer. Ten-cent coin (dime) is shown for comparison.

(Courtesy Gary K. Roberts, DDS.)

In addition to direct tissue destruction by the deforming bullet, fragmentation may occur when a bullet strikes bone and sends bone and bullet fragments in several directions. These secondary missiles cause injuries within the body similar to those from bullet fragments and may even exit the body to injure bystanders. A second injury mechanism of terminal ballistic bullet behavior is temporary cavitation, which occurs at all velocities to some degree but becomes a significant wounding mechanism factor only at high velocities. The temporary cavity is created by radial dispersion of tissue by the bullet surface as a result of acceleration of tissue away from its path. A permanent cavity occurs when a bullet or fragment crushes tissue. In high-velocity bullet wounds, the temporary cavity may be many times larger than the permanent cavity. This wave is well tolerated by most elastic tissue, such as muscle, bowel, and lung; however, inelastic tissues, such as liver or brain, do not tolerate it and may be severely damaged by the temporary cavity.

Bullet motion in flight is described by rotation, yaw, and pitch. The rifle grooves cut into the inside of the barrel cause the bullet to spin around its long axis, just like a football thrown in a tight spiral. Yaw and pitch describe bullet motion left or right, or up and down relative to the long axis of the bullet. In wound ballistics, yaw is used to describe both axes of motion. A rifle bullet will usually yaw after striking any object outside the body, such as a tree branch, belt, or clothing, and when striking skin and other tissue within the body. Yaw can result in complete end-over-end rotation of the bullet within tissue, causing the bullet to increase the area that is crushed as the entire side profile of the bullet passes through the tissue. Bullets with round ends, for example the .45 automatic Colt pistol bullet or round musket balls, routinely do not yaw, and produce wound channels equal to their caliber or expanded caliber. Yaw causes maximum damage at 90 degrees of rotation, when the entire side profile of the bullet crushes tissue. This factor, combined with any bullet expansion, can cause the exiting bullet to produce a much larger wound than when it entered.

To allow laboratory comparison of projectile designs and to study the effect of velocity and expansion, experimental wounding profiles have been described using ballistic gelatin, which accurately simulates human muscle tissue. These wounding profiles show the various aspects of potential ballistic injury, including cavitation, yaw, and fragmentation (Figures 24-14 and 24-15).¹⁹ The total effect of high energy, fragmentation, expansion, yaw, and temporary cavity formation results in tissue injury. Although the kinetic energy formula yields the total energy available to cause injury, the physical behavior of the projectile(s) and the transited tissues are the actual determinants of the complete injury pattern. The type of tissue struck is the most important factor. As can be seen from Table 24-1, the .22-caliber long rifle rimfire bullet has a low mass and velocity and thus a low muzzle energy, yet more fatalities have occurred from this round than from any other. It is very inexpensive, can be fired from a number of rifles and handguns, is commonly used to hunt game, and is not thought of as particularly dangerous by inexperienced hunters. For these reasons, more people are shot by this cartridge than by any other single bullet type. The bullet is highly lethal when striking the brain, heart, or a major blood vessel.* Rubber or plastic bullets, although generally not used for hunting, may be encountered. These bullets travel at about 61 m/sec (200 feet/sec) and will not usually penetrate skin, although at short ranges (under 15.2 m [50 feet]) they can cause fractures, eye trauma, and other blunt injuries.¹⁹

FIGURE 24-14 Wound profile of a .223 rifle bullet in 10% ballistic gelatin showing the permanent and temporary cavities and the effects of tumbling and fragmentation.

FIGURE 24-15 The path of a test bullet through ballistic gelatin suggests the amount of tissue damage that a hunting bullet can do inside the human body, even if entrance and exit wounds are small. The data for this bullet are given with Figure 24-13.

(Courtesy Gary K. Roberts, DDS.)

Other rare problems associated with firearms are explosions that occur within the firearm itself. These can cause burns or fragment types of injuries. When firearms are loaded with excessive amounts of powder or when the wrong powder is used in reloading bullets, the resultant detonation may cause the frame or cylinder of the firearm to explode. The burning powder or fragments of metal can cause injuries to the shooter. These injuries usually occur to the face and hands; penetrating eye injuries are also common. Obstruction of the barrel of the firearm by snow, mud, or other foreign material may cause a similar explosion.

Trap Injuries

Traps are designed either to kill animals or to capture them alive and uninjured. The latter type poses no risk to humans unless they should happen upon a trap and attempt to free the animal or otherwise approach the trap. The trapped animal often will bite or claw anyone within range. Leghold traps designed to kill or injure an animal may occasionally cause problems for unwary hikers or campers. These traps have a spring-loaded jaw that closes when triggered by something touching the trigger plate, usually involving only 0.5 to 1 kg (1 to 2 lb) of pressure. Most injuries involve the foot, but any area of the body that can fit between the jaws potentially can be injured. The jaws can be released by compressing the spring controlling the jaws (Figure 24-16). Very large traps used to trap poachers or to catch large animals, such as tigers or bears, cannot easily be released without help. These traps may also be attached to large weights, such as logs or concrete blocks, to prevent escape. Fortunately, most of these large traps are now collector’s items and not used in the field.

FIGURE 24-16 A, A leghold trap set. B and C, A leghold trap sprung. D and E, To release a trap that has been sprung, stand on each end of the trap and compress the spring.

Many injuries occur when the person setting the trap inadvertently causes the trap to spring before being set in the ground. This often causes hand and finger injuries, especially with amateur trappers unfamiliar with the type of trap (Figure 24-17). Unconventional traps, such as snares, deadfalls, and pit traps, may rarely be encountered, but the mechanisms and types of injuries are quite variable. Trap guns are illegal in most areas of the world; injuries are similar to gunshot wounds.

FIGURE 24-17 Spring traps must be set carefully to avoid injury to the person setting the trap.

Treatment of Hunting Injuries

Treatment of hunting injuries involves standard principles and priorities of trauma care. Airway, breathing, circulation, bleeding control, immobilization of the spine and fractured extremities, wound care, and stabilization of the victim for transport should be performed in an expedient manner. The victim should always be disarmed to prevent accidental injury to the rescuer or further injury to the victim. Removing the firearm or arrow from the vicinity of patient care is usually sufficient, but ideally the firearm should be made safe by removal of the ammunition and opening the firing chamber. Arrows should be placed in a quiver, or the points may be wrapped in cloth to prevent injury.

Management of common traumatic injuries and illnesses, such as hypothermia and mountain sickness, is no different than normal except for one important point: always disarm the victim. A victim with a charged weapon and a head injury or change in mental status for any reason presents immediate danger to a well-meaning rescuer. If the person attempting to offer aid to an injured hunter is not familiar with weapons, it is usually best to move the weapon several feet from the victim and point it in a direction where accidental discharge will do the least harm.

Arrow Injuries

Lacerations from razor-sharp hunting points are not unusual and can be treated like any similar laceration. The wound should be irrigated, any foreign material removed, and the laceration closed primarily. Victims pierced by an arrow should be stabilized, and the arrow should be left in place during transport, if possible. Attempts to remove the arrow by pulling it out or pushing it through the wound may cause significantly more injury and should be avoided. It is acceptable to cut off the shaft of the arrow and leave 8 to 10 cm (3 to 4 inches) protruding from the wound to make transport easier if this can be accomplished with a minimum of arrow movement. A large pair of paramedic-type shears can usually cut through an arrow shaft if it is stabilized during cutting. The portion of the arrow that remains in the wound should be fixed with gauze pads or cloth and tape. A similar approach should be used for spears and knives. The victim should be transferred as quickly as possible to an operating room, where the arrow can be removed under controlled conditions. Radiographs are helpful to identify associated anatomic structures before removal is attempted in the operating room (Figure 24-18).

FIGURE 24-18 Arrow wound to the left side of the neck near the mandible. The shape of the wound resembles the blades of the broadhead as shown in Figure 24-4.

Gunshot Wounds

Myths About Gunshot Wounds

Many myths associated with the management of gunshot wounds should be repudiated.

Myth 1: The size or caliber of the bullet can be determined by the size of the wound. In truth, skin is quite elastic and has high tensile strength. Although a knife or arrow can cut the skin, a blunt bullet must crush the tissue by stretching. This stretching occurs until the bullet passes through and then retracts, causing the wound in the skin to be smaller than the caliber of the bullet.

Myth 2: The size of the wound determines whether it is an exit or entrance wound. Actually, the bullet usually tumbles or yaws after striking the skin and soft tissue; if the bullet exits while still tumbling, the exit wound may be larger than the entrance. This commonly occurs when a missile strikes an arm or leg where the bullet is in midtumble at 90 degrees when exiting. Often the bullet fragments and only a small portion of the bullet exit, making the exit wound much smaller than the entrance. In addition, pieces of bone or tooth may exit, causing an odd-size wound.

Myth 3: The path of the bullet can be determined by connecting the entrance and exit wounds. This myth may lead to inappropriate intervention in gunshot wounds. For example, a gunshot wound victim had two wounds about 15 cm (5.9 inches) apart on his upper thigh, and they were initially thought to be an entrance and exit wound. The patient developed abdominal pain, and on chest radiograph it was noted that there were two bullets in the left chest. Subsequent surgical intervention revealed injury to the colon, spleen, bowel, stomach, diaphragm, lungs, and subclavian vessels. So, what appeared to be entrance and exit wounds were actually two gunshot wounds sustained while the patient was lying supine.

The outcome of most gunshot and blast wounds depends primarily on the body part that has been injured and secondarily on the environment in which the injury occurred and the quality and timeliness of medical intervention. Although knowing the type of weapon and the physics of ballistics and blast can help predict the extent of physical damage, there is no substitute for attention to detail when examining the patient.

Emergency Department Care

Emergency department care of the gunshot wound victim includes securing the airway, placing two intravenous lines in unaffected extremities, performing cardiac monitoring, and providing oxygen therapy. The patient with a neck wound and expanding hematoma should be endotracheally intubated as soon as possible. If endotracheal intubation is not possible, a needle cricothyrotomy followed by a surgical cricothyrotomy should be performed. Relief of tension pneumothorax with a needle or tube thoracostomy or occlusion of a sucking chest wound should be done immediately. Any external bleeding should be controlled by direct pressure. In a wilderness situation, a tourniquet may be necessary to control significant bleeding.

A radiograph should be obtained of the involved area, and where there is a presumed entrance wound without an exit wound, multiple radiographic studies may be needed to find the location of the bullet. On rare occasion, bullets have been observed to embolize from the chest area via the aorta to the lower extremity arteries or to the heart via the vena cava. A type and crossmatch and basic trauma laboratory tests should be performed. Tetanus toxoid and immunoglobulin should be administered as indicated by the victim’s history.

Broad-spectrum antibiotics should be administered to cover the wide range of pathogens associated with gunshot wounds, especially with complex wounds to the abdomen and extremities. The bacteriology of gunshot and blast injury wounds is quite complex. There are a number of environmental pathogens, including soil and water bacteria, such as Clostridium, Aeromonas, Staphylococcus, Streptococcus, Bacteroides, and Bacillus. These bacteria and associated bacteria on the victim’s clothing and skin account for the majority of infections in soft tissue. Wounds penetrating the abdomen increase the presence of Pseudomonas, Proteus, Escherichia coli, and other coliforms. Systemic antibiotics should be started as soon as possible and continued for at least 24 hours. Although there is no specific antibiotic that will cover all organisms, selection of antibiotic should be on the basis of probable type of infection. Cellulitis and necrotizing soft tissue infections can be treated with ceftriaxone plus metronidazole plus gentamicin. Intra-abdominal infections can be treated with the same regimen or cefotetan, and ampicillin–sulbactam can be substituted for ceftriaxone, clindamycin for metronidazole, and ciprofloxacin for gentamicin. There is no substitute for drainage of abscesses and empyemas, excision of devitalized tissue, and removal of foreign debris. Topical antibiotics have not been shown to be useful. Surgical debridement and systemic antibiotics are the mainstays of prevention and treatment of wound infection.

Victims in shock should be taken to the operating room immediately to control bleeding. If this is not possible, type O-negative or type-specific blood should be transfused. Autotransfusion, when available, can be an ideal way to replace lost blood in the victim in shock. Starch or other blood substitutes may raise the blood pressure temporarily, but large amounts of crystalloid fluids may cause increased bleeding. Hypotensive resuscitation, which allows the patient to remain relatively hypotensive as long as organ perfusion is adequate, may be the best intervention if an operating room is not readily available. A systolic blood pressure of 80 mm Hg may not be “normal,” but it may be sufficient for a supine patient. Increasing the blood pressure to 110 mm Hg may seem “normal,” but it may also cause rebleeding and irreversible shock. Hypotensive resuscitation should be the standard unless the patient loses his or her pulse or level of consciousness. At that time, blood products are the fluids of choice, followed by a starch such as hetastarch (Hextend). Level of consciousness and return of pulse should be the clinical goals. Once the bleeding is controlled, fluid resuscitation based on physiologic criteria, such as blood pressure, hematocrit, oxygenation, and acid-base status, can be used. Military antishock trousers or pneumatic antishock garments have not been shown to be beneficial in the treatment of shock secondary to penetrating trauma. Emergency thoracotomy is indicated for victims who have lost vital signs shortly before reaching the emergency department or while in the emergency department. Injuries to the heart or great vessels can be occluded with Foley catheter balloons, pericardial tamponade can be relieved, and the aorta can be cross-clamped. Hypothermia is commonly unrecognized in the trauma victim and may lead to coagulopathy, cardiac arrhythmias, or electrolyte disturbances. Rectal temperatures should be obtained and only warmed fluids and blood given to the victim.^13,^26,^33,⁶⁰

Wounds from high-velocity bullets are similar to other types of wounds, and standard rules of debridement should be followed. Wide debridement of normal-appearing tissue is unnecessary and should not be done. In general, victims of gunshot wounds should be evacuated quickly and stabilized if possible. Most victims (80%) of gunshot wounds to the chest who survive the first 30 minutes can be treated with a thoracostomy tube and observation.³³ The amount of blood that is drained from the thoracostomy tube determines whether operative intervention is necessary. Draining more than 1500 mL of blood immediately or more than 200 mL/hr for over 4 hours is an indication for thoracotomy. Signs of pericardial tamponade are an indication for immediate pericardiocentesis and operative repair. All gunshot wounds to the abdomen should be explored in the operating room. These include all penetrating injuries below the nipples and above the symphysis pubis.

Radiographs should be used to identify bullets, bullet fragments, and bony injuries. Extremity wounds can be treated conservatively unless signs of vascular injury are present. Signs of arterial injury include pulsatile bleeding, expanding hematoma, absent pulses, presence of a thrill or bruit, or an ischemic limb. Experience in combat has shown that vascular injuries do best when identified and treated immediately. However, life takes priority over limb, and a tourniquet may be needed to control vascular bleeding that may ultimately lead to loss of the limb. Obviously, major bony injuries and nerve injuries eventually need operative therapy, but immediate intervention is rarely necessary. Most important, the underlying injury cannot be determined by examination of the external wound.

Vascular injuries may not be identified during the initial examination; therefore noninvasive, portable, Doppler ultrasound studies can be extremely valuable in the emergency department. Contrast angiography should be performed on any victim with a suspected vascular injury. The removal of the bullet or bullet fragment is not necessary unless the bullet is intravascular, intra-articular, or in contact with nervous tissue, such as the spinal cord or a peripheral nerve. Bullets found during exploratory laparotomy or wound debridement should be removed, but it is unnecessary to explore soft tissue, such as muscle or fat, solely to remove a bullet. Shotgun pellets that have minimal penetration can be removed from the skin with a forceps. Plastic or cloth wadding found in superficial shotgun wounds should be removed. Shotgun blasts may produce large soft tissue defects that need extensive debridement and either skin grafting or surgical flap rotation to maximize coverage. Patients with powder burns should have as much of the powder residue removed as possible with a brush under local anesthesia. The powder will tattoo the skin if it is not removed, and the deep burns may need dermabrasion or surgical debridement (Figure 24-19).^13,^60,^61,⁶³

FIGURE 24-19 A, Close-range 12-gauge shotgun wound to the right side of the upper chest. The large central wound was caused by the plastic wadding, and the pellets have struck at an angle toward the shoulder. The patient was turning to the right when shot. The external appearance of the wound indicates a massive injury to the chest. B, Chest radiograph of the patient in A. No pellets have penetrated the chest, and there was no pneumothorax, pulmonary contusion, or vascular injury. The injury was totally superficial, and the patient was admitted for observation and local wound care.

Retained lead bullets and shotgun pellets for the most part are not hazardous; however, when they are within joint spaces or the gastrointestinal tract, significant amounts of lead can be absorbed and toxicity can occur. Infection of gunshot wounds is common, especially with large tissue injuries, injuries to the bowel and wounds that are highly contaminated with clothing or other debris. Despite myths to the contrary, bullets are not sterile. Certainly, clothing, skin, and other substances that the bullet may acquire during flight are not sterile.⁵²

Prevention of Hunting Injuries

Most state fish and wildlife agencies have recognized that hunters are at risk for injuries and have tried to develop programs to minimize morbidity and mortality. National organizations such as the Boy Scouts of America and the National Rifle Association have been teaching firearm and hunting safety for decades. The Hunter Education Association and the IHEA have attempted to identify high-risk groups and situations by collecting data on both fatal and nonfatal hunting-related injuries. IHEA-approved hunter safety programs are available in every state, and all states except Alaska, Massachusetts, and South Carolina require the course before issuing a license to hunt. These courses are roughly 12 hours long and cover hunter responsibility, firearms and ammunition, bow hunting, personal safety, game care, and wildlife identification. They stress respect for the wilderness and a rational approach to game management. All hunters, potential hunters, and persons going into hunting areas should take one of these courses. Approximately 650,000 hunters complete a hunter safety course annually. Since the first course given in Kentucky in 1946, more than 18 million hunters have been certified.

Most injuries could probably be prevented by following a few simple rules. Nonhunters should be aware of hunting seasons and designated hunting areas and wear international orange clothing while in hunting areas (Figure 24-20). Hunters should always be sure of their target before shooting, use safety harnesses in tree stands, and use appropriate technique and tools for cleaning game. Tree stands should be well constructed. Hunters should never consume alcohol or mind-altering drugs that might interfere with their judgment. Eye protection in the form of safety glasses should be worn while hunting or target shooting to prevent injuries from ricocheting fragments and shotgun pellets. High-frequency hearing loss is common in hunters because of the loud report of the firearm. Although earplugs and headsets can protect the hunter, they are impractical for most hunting and are used mainly for target shooting. Some hunters use a single ear plug for the ear closest to the muzzle of the firearm. This protects the ear most likely to be injured but still allows the hunter to hear approaching game and other hunters. Bow hunters should always use wrist and finger protection to prevent injuries from the arrow fletching and the bowstring. All arrows should be carried in a quiver until ready for use. The broadhead arrow should always be pointed away from the hunter. These few steps would probably eliminate most hunting injuries.^45,⁴⁷

FIGURE 24-20 Hunter wearing bright orange clothing, which is essential to distinguish a human from the background and avoid an accidental shooting. Many accidental shootings have occurred when one hunter’s movement was mistaken by another hunter for the movement of an animal.

Fishing Injuries

Sport fishing is associated with a large number of relatively minor injuries compared with hunting. The usual problems associated with outdoor recreation are common among fishermen: sunburn, frostbite, hypothermia, near drowning, sprains, fractures, motion sickness, and heat illness. Lacerations are relatively more common because of the use of knives to cut bait and fishing lines and to clean fish. These lacerations are often contaminated with a variety of marine and freshwater pathogens that may increase the incidence of wound infection. Thorough debridement of the wound and copious irrigation with sterile saline solution are the best initial methods to prevent infection. If sterile saline in not available, then the cleanest water available should be used. Chlorhexidine scrub incorporated into a brush makes an excellent wilderness cleansing device.

Fishhook Injuries

Fishhooks are designed to penetrate the skin of fish easily and to hold fast while the fish is played and landed. To perform this dual role, they are extremely sharp at the tip, have a barb just proximal to the tip, and are curved so that the more force applied to the hook, the deeper it penetrates. Fishhooks may be single or in clusters of two, three, or four to increase the chance of catching the fish. Some state fishing laws limit the number of hooks allowed on a single line when fishing for certain game fish, to make fishing more sporting. The greater the number of hooks on a lure or line, the greater the chance of catching a fisherman. The most common fishhook punctures occur when fish are removed from hooks. The combination of sharp hook, slippery fish, and inexperienced fisherman leads to puncture wounds or embedded fishhooks. Many fishermen use commercial fishhook removers or large Kelly forceps to remove hooks. Some fishing guides simply cut the hook with a side-cutting pliers; they believe the remaining segment of hook will eventually oxidize in the fish and disintegrate. Often, a fishhook is stepped on with a bare foot or a fisherman catches himself or another person on the backcast.

Fishhooks can penetrate skin, muscle, and bone, and they may pierce the eye or the penis. Care must be taken in removing a fishhook so that further damage to underlying structures is avoided. The first step is to remove the portion of the hook that is embedded from any attached lines, fish, bait, or lure. This is best done with a sharp side-cutting pliers. A bolt cutter may be needed for large, hardened hooks such as used in shark or swordfish fishing. Treble hooks, with three separate hooks attached at a single eye, are designed to improve the chance of catching a fish going after a live or artificial bait (Figure 24-21). They are also used in “snagging” fish, in which the line with one or more treble hooks is pulled through the water in an attempt to snag a fish on any part of its body. They may be found on many types of fishing lures, some with three or more treble hooks on a single lure (Figure 24-22, online). When this type of hook is embedded, often more than one of the hooks is involved. Cutting the embedded hooks off the lure or the treble hook will prevent further injury before removal. Most fishermen carry a multitool or needle-nose pliers for removing hooks and lures from fish. These same tools can be used in the field to remove or stabilize embedded hooks.

FIGURE 24-21 Typical treble hook attached to a fishing lure.

FIGURE 24-22 Examples of types of fishing lures with various arrangements of hooks.

A number of techniques are used for removing embedded fishhooks, but all involve a certain amount of movement of the hook, which causes increased pain. A local anesthetic should be infiltrated around the puncture site to minimize pain and movement of the patient. The following method can be used if the hook is not deeply embedded (Figure 24-23, E ). Pressure is applied along the curve of the hook while the hook is pulled with a snapping motion away from the point. Because the barb is on the inside of the curve of the hook, this enlarges the entrance hole enough to allow the barb and point to pass through. Sometimes a string looped through the curve of the hook facilitates the process. If the hook is deeply embedded, pressure can be applied along the curve of the hook to advance it further into the tissue until the point and barb penetrate the skin at another place on the surface, and then the barb can be cut off and the remainder (shaft) of the hook backed out (Figure 24-23, A to D).