Lami's theorem. (mechanics). When three forces act on a particle in equilibrium, the magnitude of each is proportional to the sine of the angle between the other two. 1  Facebook.
Variable reactions: Brown recluse spider's bite can cause no reaction, a mild reaction, an immediate or a delayed reaction. With a significant reaction a which blister appears after bit. The surrounding skin becomes hard, swollen & can be red, white & blue. A deep lesion can develop which can eat through fat and muscle.
The bite of a common sac spider (Cheiracanthium) can be misdiagnosed as a brown recluse spider bite. Injuries develop in a similar manner but are much less severe. Reactions, such as swelling, slow healing, and ulcerated sores around the bite site, are similar enough to be confusing.