Final answer:
Developmental anatomy is the field that studies the structural changes through the lifespan, including the aging process.
Step-by-step explanation:
The branch of anatomy that studies the structural changes that occur as one ages is developmental anatomy. This field examines the changes in organismal structure over the course of life, encompassing not only the process of aging but also the development from conception through maturity. Unlike regional anatomy, which focuses on specific regions of the body, or surface anatomy, which deals with external body landmarks important for clinical examination, developmental anatomy is specifically concerned with temporal changes.