Osteoporosis depends on how much bone mass you are able to attain during your youth. Since your bones are constantly being renewed while you are young. While it is renewing it is breaking down old bone slower than it makes new bone, which is how you increase your bone mass. As you age your bone mass is however lost faster than it is created. The more bone mass you have attained the less likely you are to get osteoporosis (“Osteoporosis: Causes”, 2013). Osteoarthritis is related to aging mostly. The cartilages water content increases and the protein makeup of the cartilage degenerates as you age. Overtime the cartilage begins to flake or form tiny crevasses which are degeneration. You start to feel pain and have limited joint mobility as you loss cartilage; the cushion begins to fade so friction happens between the bones. Spurs can begin to form around the joints due to the damage to the cartilage. If osteoarthritis is found between multiple members of the same family, it usually implies there is a genetic basis for this condition. Osteoarthritis caused by hereditary can sometimes, but rarely be caused by defects in collagen (“Osteoarthritis (Degenerative Arthritis) Causes”, n.d.) Muscle atrophy is when your muscles simply just waste away. The main cause of this is simply lack of physical activity. Example is if you are injured or bedridden due to a medical condition (Pietrangelo, n.d.). In the case of the thin, small boned 84 year old lady, due to her age we can almost guarantee she has some form of osteoarthritis. Also, due to her age her she is losing more bone mass faster than she can make it so she probably has osteoporosis. Usually, by the time you are 84 you get around a little slower