The Anatomy of an Injury
Injuries to the body can take many forms: a contusion or sprain, inflammation from arthritis or tendinitis, a sore back or an aching head brought on by stress. All have one thing in common: irriation or damage to the body's tissues.
Say you're running toward home plate, savoring your imminent triumph (and composing your victory speech in your head) when — wham! — you hit the dirt.
Maybe you pulled a muscle? Or twisted an ankle? Either way, you've done some damage. If the fall was sudden enough, you've probably torn some muscle (or tendon or ligament) fibers, triggering an almost immediate response in your body. Nerves send a pain message to your brain, which in turn tells you to stop what you were doing lest things get any worse. Blood is quickly sent to the injury site, carrying the body's defensive foot soldiers (white blood cells) and stabilizing the area until help arrives. It's the inflammatory response in action.
The term inflammation applies to more than one condition. Local inflammation is associated with an injury or infection in one part of the body. Systemic inflammation is often tied to multisystem, long-term diseases like lupus. These conditions, known as autoimmune disorders, are the result of the body's immune system mistaking its own cells for foreign invaders.
Now, say you're sitting in your favorite chair, watching the evening news, when you feel an ache in your knee. It's been there for awhile, so long that you hardly notice it anymore. That ache is also the result of inflammation, which in this case is occurring as a result of an old injury. There's no emergency here, no microbial intruders to destroy, but your body is reacting to this trauma in the same way it would to any other: with inflammation.
Although it's the source of countless health problems, inflammation can be a good thing. In inflammation, the body sends blood to the site of some kind of trauma to protect itself from infection or further injury. Signs of inflammation include pain, redness, warmth, and swelling (edema). If the inflammation is happening in a joint or muscle, you'll also experience stiffness and some loss of function.
All of this is good, of course, unless that inflammatory process gets stuck in the “on” position. This can be caused by a few things: Maybe you're perpetuating the damage by continuing to do the things that cause the injury in the first place, or you're developing a chronic condition, like arthritis or bursitis, in which the inflammation is doing nothing but creating more inflammation. Ongoing inflammation can cause any number of problems, but in the case of everyday aches and pains it usually means swelling and discomfort that never go away. It can also mean damage to the tissues in the area, including cartilage and bone.