Superficial Fascia of the Cheek and Nasolabial Area Shown in P45 Sheet Plastination

초록

Purpose: To determine the extent of the superficial fascia of the cheek, and elucidate the relationships between the nasolabial fold and superficial fascia on histology and P45 sheet plastination. Methods: Two centimeter width specimen of the nasolabial area were harvested from the skin to periosteum. Ten-μm sections were stained with Masson trichrome, and observed under light microscope. Three head and neck specimens were sliced in horizontal (46 slices), coronal (30 slices), and sagittal (29 slices) sections using P45 sheet plastination (special polyester resin corrosion-resistant method to preserve biological sectional specimens in situ). Results: P45 sheet plastination revealed that the superficial fascia in the cheek area is generally composed of 3 layers: a superficial fatty layer, a membranous layer, and a deep fatty layer. Anteriorly, the MSF extended to the posterior border of the zygomaticus major muscle, enveloping this muscle, and then to the lateral border of the orbicularis oculi muscle. Posteriorly, the MSF extended to the anterior border of the parotid gland, and then was continuous with the parotid fascia. Superiorly, the MSF extended to the line from the tragus to the alar base. Inferiorly, the MSF extended to the line from the mandibular angle to the mouth corner. Below this line, SMAS continued to the upper border of the platysma muscle. On histology and P45 sheet plastination, the nasolabial fold consisted of the superficial fatty layer of superficial fascia (SFS). At the beginning of the alar groove level, the nasolabial groove was located on the point where the medial limit of SFS met the levator labii superioris (LLS). At the alar base level, the nasolabial groove was located where the medial limit of the SFS met LLS. At the mouth corner level, the nasolabial groove was located where the medial limit of the SFS met the modiolus, including the orbicularis oris.