Complex sentence: The superior border is long, thin, and sharp, and serves for the attachment of the temporal fascia; the inferior, short, thick, and arched, has attached to it some fibers of the masseter.
Split into simpler sentences: The superior border is long, thin, and sharp, and serves for the attachment of the temporal fascia. The inferior border, short, thick, and arched, has attached to it some fibers of the masseter.