BACKGROUND The chin is an important component of facial harmony, and deficient chins are associated with unattractiveness. Previous studies have reported microgenia as the most common subtype of chin deformities. OBJECTIVE To investigate the prevalence and severity of microgenia in a Chinese population through facial anthropometric analysis. METHODS A total of 800 Han Chinese adults from various age groups of both sexes were recruited for facial anthropometric measurements and photographic analysis. Chin deficiencies in both sagittal and vertical dimensions were evaluated using G-S-P angle, chin retrusion distance, and Sn-Vl/Sn-Me ratio criteria. RESULTS In the sagittal dimension, microgenia was present in 60.7% of men and 68.6% of women according to the G-S-P angle criterion, and the angle significantly decreased with age in women (p , .05). According to the chin retrusion criterion, microgenia was present in 38.7% of men and 32.3% of women, and the retrusion distance significantly increased with age in both sexes (p , .05). Vertical microgenia was present in 69.6% of men and 81.9% of women according to the Sn-Vl/Sn-Me criterion, and the ratio gradually increased with age in both sexes (p , .05). CONCLUSION Microgenia is common among Chinese, particularly in women, and the prevalence and severity increase with age.

BACKGROUNDBotulinum toxin has been widely accepted as safe and effective for the treatment of glabellar lines, and previous studies have classified glabellar contraction patterns into 5 categories.OBJECTIVETo classify the glabellar contraction patterns among a large-scale Chinese population and provide a reference for injections in Chinese patients.METHODSFour hundred eighty-nine Chinese subjects who received botulinum toxin for the treatment of glabellar lines were selected for a retrospective photographic analysis of their glabellar contraction patterns. Using 2 separate previously established classification systems, the patterns were analyzed and classified by a panel of certified Chinese dermatologists.RESULTSTwo separate classification systems showed different distributions of glabellar contraction patterns among Chinese compared with Caucasians and Koreans. The classifications allowed for identification of the most frequent patterns in Chinese, which were “converging arrows” and “11” pattern, and provided references for identifying the most important muscles.CONCLUSIONBoth classification systems are applicable to the Chinese population with varying distributions. Because the classification system of de Almeida and colleagues focuses more on the muscles involved in the formation of glabellar lines, the authors' subjects classified according to this system displayed a more balanced distribution among the 5 patterns. This provides an easier reference for dermatologists in daily clinical practice and guiding treatment strategies.

Background Injection of cross-linked hyaluronic acid (CLHA) has been traditionally used to treat wrinkles and provide volume. Recent studies have also shown that intradermal placement of CLHA provides lasting secondary effects as an effective method for improving skin appearance and physiology. Objectives The aim of this study was to investigate the biostimulatory effects and potential underlying mechanisms induced by repeated intradermal microinjections of small-particle cross-linked hyaluronic acid (SPCLHA) for skin rejuvenation. Methods Eight subjects with photoaged forearm skin underwent three intradermal microinjections of SPCLHA and isotonic sodium chloride (control). At 0, 4, 8, 12, and 24 weeks, biophysical parameters were measured, and skin biopsies were obtained at 12 and 24 weeks for assessment using histological and immunohistochemical analyses, transmission electron microscope and real-time fluorescence quantitative polymerase chain reaction. Results SPCLHA treatments significantly improved skin appearance and physiologic functions starting at 8 weeks. Histologic examination revealed thickening of the epidermis, more red-stained collagen fibers in the dermis, and increased formation of blood vessels in SPCLHA-treated skin. Immunohistochemical evaluation showed increased collagen deposition, proliferation of keratinocytes and fibroblasts, and cutaneous vascularity in SPCLHA-treated skin compared with controls. Fibroblasts appeared morphologically stretched with well-developed rough endoplasmic reticulum. Gene expression concerning various extracellular matrix (ECM) proteins and growth factors were upregulated at 12 weeks and several genes remained upregulated at 24 weeks. Conclusions Intradermal microinjections of SPCLHA can stimulate production of collagen and other ECM components, restore the structural integrity of dermal microenvironment and may be considered an effective method for skin rejuvenation.