Anatomical features of nasolabial fold

Objective To investigate the anatomic characteristics of the nasolabial fold and to give an accurate description and definition of it in order to to provide theoretical basis for plastic, cosmetic and maxillofacial surgery. Methods Ten (20 sides) adult fresh bodies with vascular perfusion of formalin fixed after morphological observation under a 10 × magnifying len. Results Nasolabial fold was a border between fat-rich zone and non-fat zone in the midfacial region. The nasolabial fold derived from nasal alar skin point in the transverse portion of nasalis, and ended at the outer skin point of zygomaticus major muscle in the mouth. From the anatomy point of view, the nasolabial fold was divided into three segments: the upper, the middle and the under. The upper segment ( Ⅰ ) was the transverse portion of nasalis, (20. 38± 0. 74) mm in length; the middle section ( Ⅱ ): levator labii superioris,(17.13 ± 0.57) mm in length; the under segment (Ⅲ ): modiolus, (20. 81 ±0. 70) mm in length. The nasolabial fold was a connecting region where seven mimetic muscles inserted into the skin point. Superficial musculoapneurotic system (SMAS) and the nasolabial fold were composed of seven mimetic muscles belonging to the same layer. Conclusions The nasolabial fold is a region where the seven mimetic muscles insert into the skin point for connection, and regardless of age, it is an eternal existence. The nasolabial fold is different from the nasolabial wrinkle formed with facial aging and the nasolabial ridges formed by facial mimetic muscles changes. Key words: Nasolabial fold; Microdissection; Mimetic muscles