Which of the following structures normally does not appear as areas of increased activity on the bone images of adults?

In the context of bone imaging in adults, the phalanges typically do not exhibit increased radiopharmaceutical uptake compared to other structures. Areas of increased activity on bone scans usually indicate either physiological processes (such as growth or remodeling) or pathological conditions (such as inflammation, infection, or tumors). The phalanges, being small bones on the fingers and toes, generally have a lower metabolic rate relative to larger joints or areas with more significant stress or activity.

On the other hand, structures like the glenoid fossa, sternoclavicular joints, and vertebral column often show increased activity due to their roles in load-bearing, mobility, and various physiological stressors. These areas are more likely to demonstrate variations in uptake that indicate underlying conditions or physiological activity compared to the phalanges, which tend to remain more stable in terms of metabolic activity in the adult population. Thus, the phalanges are the most likely to not present as areas of increased activity on bone imaging in adults.