Final answer:
The frontalis muscle is the frontal belly of the epicranius muscle, and together with the occipitalis, forms the occipitofrontalis muscle of the scalp connected by the epicranial aponeurosis.
Step-by-step explanation:
The muscle also known as the frontal belly of the epicranius is indeed the frontalis muscle. Together with the occipitalis muscle, the frontalis forms the occipitofrontalis muscle, which covers the scalp. The frontalis muscle is responsible for moving the scalp and raising the eyebrows, contributing to facial expressions.
Contrary to the statement about a historical comparison to an apple, the connection between the frontalis and occipitalis muscles is not made by muscle fibers but by a fibrous tendon known as the epicranial aponeurosis or galea aponeurotica. The term "epicranial" reflects its location over the cranium, and "aponeurosis" denotes a flat, sheet-like tendon. This strong connective tissue spans the top of the skull, providing a foundation for the frontalis and occipitalis muscles to work together in generating facial expressions and contributing to the intricate movements of the scalp.