Which structure is a broad, flat extension of the muscle that serves a similar function as a tendon?

An aponeurosis is a broad, flat extension of a muscle that provides a means for muscle fibers to connect to other muscles or structures, functioning similarly to a tendon. Unlike tendons, which typically have a narrow, cord-like structure, an aponeurosis covers a larger area and can attach to multiple muscles or regions, allowing for force distribution across a broader surface area. This feature is particularly useful in muscles that perform tasks requiring widespread movement or stabilization of large muscle groups.

The distinction of an aponeurosis lies in its structure and function as a connective tissue that acts as a sheet, linking muscles to their respective attachment points with a unique configuration, which can facilitate movements in various directions while maintaining stability and support.