What are the places on the head called where the surface changes?

The term that accurately describes the places on the head where the surface changes is "contours." This term refers to the curvatures and shape variations of the head, which are important for hairstyling and cutting techniques. Understanding the contours of the head helps a stylist create more flattering hairstyles that complement the client's face shape and bone structure.

In hairstyling, recognizing the contours allows for precision in layering, blending, and texturizing hair. It also helps in determining how the hair will fall and frame the face, ensuring that the final look enhances the client's features.

The other terms mentioned do not specifically refer to these changes in surface. Edges typically refer to the sharp lines created during cutting, perimeters denote the outer boundary of a haircut, and landmarks are reference points used for guidance during hairstyling but do not encompass the broader concept of surface changes on the head.