The Aesthetic Significance of the Midface: Anatomy, Facial Aging, and the Importance of Volume Reconstruction in the Midface Over the past decade, the field of medical aesthetics has been undergoing a series of major changes in conceptualization and operative techniques, and one of the key drivers of these changes has been the emergence and vigorous development of injectable fillers for the skin and soft tissues. When hyaluronic acid products were initially used in the field of medical aesthetics in the early part of the 21st century, their primary role was to fill in skin wrinkles. As more and more hyaluronic acid injectable filler preparations became available with different viscosities and durability for application in different areas, the role of injectable fillers in medical aesthetics underwent a series of changes. Today, hyaluronic acid facial rejuvenation treatments have entered the era of “total body planning”, where doctors are not only limited to the improvement of superficial wrinkles, but also go a step further by using hyaluronic acid injections to correct facial volume loss due to aging, and to rejuvenate facial contours and curves. The beauty of the face comes from the harmony of the five senses, so the midface, as an important part connecting the eyes, nose, lips, and cheeks, plays an important role in the rejuvenation of the face and the overall aesthetics. Numerous studies on facial aesthetics over the past 10 years have found that the midface is the first area to show signs of facial aging, and as a result, rejuvenation treatments for the midface have received increasing attention. The youthful face has an “inverted triangle” with the fuller midface as the top side of the triangle. As aging progresses, the midface experiences bone, muscle, and zygomatic fat pad laxity and loss, as well as skin sagging, resulting in the visual appearance of a widening of the lower face and a gradual overshoot of the “square triangle” shape. Progression of aging in the midface: The main causes of aging in the midface are bone loss at the infraorbital border, loss of subcutaneous soft tissue volume, laxity of the orbicularis oculi maintenance ligament and zygomatico-cutaneous ligament, and sagging of the orbicularis oculi muscle and zygomatico-calcaneal ligaments, which result in a weakening of the soft tissue coverage of the lower eyelid area, the appearance of bags under the eyes, the lacrimal grooves, and zygomatico-lid sulcus, and the zygomatic arch pattern that is accentuated by a weakening of the surface soft tissues. Schematic representation of the aging midface, 4A: rejuvenated lower lid and cheek, B: schematic representation of the aging midface. Midfacial soft tissue volume decreases with age Hyaluronic acid-based midfacial rejuvenation treatment options: hyaluronic acid is a linear polysaccharide substance commonly found in body tissues and is one of the components of the extracellular matrix. Hyaluronic acid injectable filler preparations vary in viscosity, supportive power and durability and can be applied to different areas of the face, with different products being selected according to the thickness of the facial skin and the firmness required for contouring different areas. Currently, hyaluronic acid injectable filler preparations with strong support and contouring power and better durability have been widely used for midface injectable fillers as the preferred option for minimally invasive midface rejuvenation treatments. Injections in the midface should first reshape the cheeks. For Chinese people, due to the flatness of the midface, more emphasis is placed on the infraorbital and cheek areas (commonly known as the “apple muscle”) as well as the basal area of the nose. For some cases of sagging skin and deepening nasolabial folds in the midface due to aging, we can consider injecting an appropriate amount into the zygomatic bone area (in front of the zygomatic arch) to achieve facial lifting effects and effectively alleviate the depth of the tear troughs and nasolabial folds. Through the comprehensive contouring of the mid-face, it shapes the youthful curve form of the mid-face and achieves the effect of rejuvenation treatment. The dosage of hyaluronic acid facial injection is also the key to rejuvenation treatment. An adequate treatment dose should be given to ensure adequate improvement in the appearance of aging and fatigue. A 4-week follow-up of injections is recommended to optimize the results of the treatment.