Final answer:
A normal age-related finding in the lower extremities of an 80-year-old woman is diminished strength bilaterally, a condition known as sarcopenia. This reflects a symmetrical decrease in muscle mass and strength due to aging, as opposed to unilateral or pathologic changes.
Step-by-step explanation:
A normal age-related finding in the lower extremities of an 80-year-old woman would be diminished strength bilaterally. This condition is known as sarcopenia, which is characterized by a gradual decrease in the ability to maintain skeletal muscle mass and occurs in later adulthood. While crepitus, joint swelling, and unilateral muscle atrophy can occur, they are more indicative of pathologies rather than normal aging processes.
During the assessment of muscle strength, if an 80-year-old woman shows reduced strength in both limbs without lateral differences, this suggests a more global and symmetrical issue linked to aging rather than a localized neurological deficit. In contrast, conditions such as MS, cerebral palsy, or the effects of a stroke would often present with unilateral deficits or specific patterns due to upper motor neuron (UMN) lesions.