What muscle encompasses the forehead and extends into the scalp's beginning curve?

The muscle that encompasses the forehead and extends into the scalp's beginning curve is the frontalis. This muscle is a part of the occipitofrontalis muscle group, which also includes the occipitalis at the back of the head. The frontalis muscle is responsible for movements of the forehead, such as raising the eyebrows and creating horizontal forehead wrinkles. Its location and function are critical because they play a significant role in facial expressions, which are essential for non-verbal communication. The way it spans across the forehead also means it contributes to the overall appearance of the forehead area, making it a key muscle in both aesthetic and functional aspects of the face.

The other options refer to muscles with different locations and functions. The occipitalis is located at the back of the head and doesn't influence the forehead area. The temporalis is primarily involved in chewing and is situated on the side of the head. The orbicularis muscle group surrounds the eyes and mouth, facilitating their movements but does not cover the forehead. Thus, the frontalis is the correct choice for this question regarding the forehead and scalp area.