Anatomical foundation of smiling and mid-lower facial rejuvenation

Objective To investigate the forming mechanism of smile anatomically,and to analyze the changes of aging characteristics of mid-lower face.Methods Ten (with 20 sides) adult fresh cadaveric heads were fixed by formalin,and then nasolabial fold morphology was observed under 10X operating magnifying glass,and compared with alteration of the middle and lower face aging features under the state of smiling and static according to observation from 50 doctors' and out-patients' photos.Results The nasolabial fold was the boundary between fatty and fat-free zone in the middle face,the lateral side of which was malar fat pad.The nasolabial fold was the linear area,which was formed by the insertions of seven mimetic muscles on the skin.When smiling,the nasolabial fold and cheek groove,got deep and extended,cheek stripe became obvious.While smiling,malar fat pad shifted up,and tear trough became deformity..64％ disappeared and 36％ getting shallow and appearance improved; orbit-malar fold showed 100％ horizontal part disappeared,74 ％ vertical part became shallow and improved,and 26％ stayed stable; mid-cheek fold showed 78％ dissovled,22％ getting shallow and improved; Labiomandibular fold showed 100％ Ⅲ degree disappeared,100％ Ⅱ degree dissovled,74％ Ⅰ degree disappeared,and 26％ getting shallow and ameliorated; submaxilla line showed 18％ getting smooth and 82％ remained.Conclusions Smiling is produced by movement of mimetric muscles,and its orgin is from nasolabial fold.A smile could make malar fat pad upwards to mask some aging characteristics of middle and lower face,which is helpful to form a younger face. Key words: Nasolabial fold;  Anatomy;  Aging characteristics;  Smiling;  Facial youngthful