Quick AnswerFacial volume loss occurs across four tissue layers at once: skin, superficial fat, deep fat, and bone. The Four Tissue Layers Behind Facial Volume LossFacial volume loss is not a single event in one tissue. The Superficial Fat CompartmentsAbove the SMAS sit discrete fat pads separated by fibrous septae, mapped by Rohrich and Pessa. Deep Fat and the Structural PlatformThe deep medial cheek fat and the suborbicularis oculi fat sit directly on bone and carry the midface. Bone recedes at the orbital rim and midface, deep fat atrophies, superficial pads descend, and the dermis thins.