In chemistry, a reaction mechanism is the step by step sequence of elementary reactions by which overall chemical change occurs. A chemical mechanism describes in detail exactly what takes place at each stage of an overall chemical reaction (transformation). It also describes each reactive intermediate, activated complex, and transition state, and which bonds are broken (and in what order), and which bonds are formed (and in what order).
Grade IV capsular contracture in the right breast of a 29 y.o. woman, seven years after subglandular placement of 560cc silicone gel-filled breast implants. Capsular contracture is a response of the immune system to foreign materials in the human body. Medically, it occurs mostly in context of the complications from breast implants and artificial joint prosthetics.
Frozen shoulder, also called adhesive capsulitis, is a painful condition in which shoulder becomes stiff and inflammed and movement becomes limited. People at risk include those with shoulder injuries, and for reasons not fully understood, those with diabetes, Parkinson's disease, hyperthyroidism, hypothyroidism, and heart disease.