This section of Dog Bite Law discusses special evidence issues which are particular to dog bite cases. Attorneys can obtain convenient, thorough lists of necessary items of evidence, as well as requests for production of evidence, in Dog Bite Lawsuit Forms.
Dog dentition is conventionally represented by a dental formula by quadrants, because dentition is bilaterally symmetrical. Thus, the canid dental formula is incisors 3/3, canines 1/1, premolars 4/4, and molars 2/3. Depending on the function of each tooth, certain types of injuries may be produced:
- The incisors of canids are relatively small, are used for nipping, and will produce small parallel grooves on bone.
- Canines are long and sharp, have small serrations along one of the borders, are used to stab and tear, and produce either punctures or gouges.
- The premolars are small, hooklike teeth, which are used to hold onto prey and will produce striations on bone.
- The molars have small, round (bunodont) cusps and are used for crushing.
- An important specialized structure, the carnassial, is produced by enlarged cusps on the mandibular first molar and the maxillar fourth premolar. These cusps lie across each other to form a scissors, which slices through the food during mastication (Hillson S. Teeth. Cambridge: Cambridge University Press, 1990:39-44).
The canine lower dental arch is narrower and shorter than the upper, and natural gaps exist between the teeth in most breeds, which may be reflected in the bite mark impressions (Clark MA, Sandusky GE, Hawley DA, Pless JE, Fardal PM, Tate LR. Fatal and near-fatal animal bite injuries. J Forensic Sci 1991;36:1256-61).
Although canine teeth are not excessively sharp, pressures >400 lb/in2 can be generated by the viselike action of the jaws of a large dog (Wilberger JE Jr, Pang D. Craniocerebral injuries from dog bite in an infant. Neurosurgery 1981;9:426-8,16; Wilberger JE, Pang D. Craniocerebral injuries from dog bites. JAMA 1983;249:2685-8). When the victim is an infant, the powerful jaws of a large dog characteristically produce bilateral or multiple depressed fractures of an infant's skull, which is relatively thin and incompletely mineralized, as well as small circular defects seen on radiographs produced by canine teeth perforations (Steinbock P, Flodmark O, Scheifele DW. Pediatr Neurosci 1985-86; 12:96-100; Pinckney LE, Kennedy LA. Fractures of the infant skull caused by animal bites. AJR 1980;135:179-80).
As a rule, dogs do not completely chew their food (Clark MA, Sandusky GE, Hawley DA, Pless JE, Fardal PM, Tate LR. Fatal and near-fatal animal bite injuries. J Forensic Sci 1991;36:1256-61). The constellation of injuries produced by a dog will depend on the specific circumstances of the dog's feeding behavior. Canids are both hunters and scavengers. Angry dogs move their heads as they bite, which tears the tissue and makes it more difficult to evaluate (Glass RT, Jordan FB, Andrews EE. Multiple animal bite wounds: a case report. J Forensic Sci 1975;20:305-14). In addition, dogs' teeth, other than molars, produce tears in clothing, rather than cuts (Bryson J. Evil angels. New York: Summit Books, 1985). The shearing action of molars can sever fibers and crush their ends, making it difficult to identify tooth marks (Id.). The fatal attack is characterized by repetitive, uninhibited biting, and the dog is relatively unresponsive to attempts to terminate the attack (Wright JC. Severe attacks by dogs: characteristics of the dogs, the victims, and the attack settings. Public Health Rep 1985;100:55-61).