Myopathology refers to which of the following?

Myopathology specifically pertains to the study of muscle diseases and conditions that impair muscle function. This encompasses various abnormalities that can arise within the muscle tissue itself, leading to weakened, painful, or dysfunctional muscles. As a result, when considering the impact of this condition, abnormal muscle function stands out as the primary concern, as it directly relates to how muscles contract, relax, and perform their intended roles in the body.

In contrast, the other options address different aspects of musculoskeletal health. Changes in bony structure relate to conditions affecting the bones, while altered nervous system activity pertains to neurological disorders that might influence muscle control without directly affecting the muscle tissue. Abnormal disc structure involves spinal disc issues that can lead to pain and mobility problems but does not inherently imply abnormalities within the muscles themselves. Thus, myopathology is most accurately defined by its focus on abnormal muscle function.