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Facial fold and crease development: A new morphological approach and classification
Tudor Sandulescu1, Marie Franzmann1, Julia Jast1
1Department of Biological and Material Sciences in Dentistry, School of Dentistry, Faculty of Health, Witten/Herdecke University, Witten, Germany.
Clinical Anatomy (New York, N.Y.)
|February 21, 2019
Summary
Facial folds like the nasolabial fold are primary structures caused by changes in the superficial musculoaponeurotic system (SMAS). Other creases result from different anatomical interactions, not SMAS changes.
Area of Science:
- Anatomical morphology
- Histology
- Facial anatomy
Background:
- Facial folds and creases are common anatomical terms.
- Their origins and distinct morphological characteristics remain unclear.
- Understanding these structures is crucial for anatomical and clinical contexts.
Purpose of the Study:
- To investigate the morphology of key facial folds: nasolabial fold (NLF), mandibular fold (MF), deep transverse forehead crease (DTFC), infraorbital fold (IOF), and upper eyelid fold (UEF).
- To correlate fold phenotypes with variations in the superficial musculoaponeurotic system (SMAS).
- To identify and compare morphological differences and similarities among these facial structures.
Main Methods:
- Postmortem histological analysis of full-graft tissue blocks including skin, subcutaneous tissue, and mimic muscles.
- Azan staining for detailed histological examination.
- Digitalization of serial sections and 3D reconstruction of tissue blocks.
- Identification and classification of SMAS architecture types.
Main Results:
- Three distinct SMAS architectures were identified: Type I (parallel fibrous septa), Type II (condensed with stronger septa), and Type III (loose connective tissue).
- Primary folds (NLF, MF, IOF, UEF) are linked to underlying SMAS architectural changes.
- Secondary creases (DTFC) result from dermal-skeletal-muscular interactions, independent of SMAS changes.
- Tertiary wrinkles (eyelid) are age-related skin redundancies.
Conclusions:
- Nasolabial, mandibular, infraorbital, and upper eyelid folds are primary structures directly influenced by SMAS morphology.
- Deep transverse forehead creases are secondary formations not related to SMAS variations.
- Eyelid wrinkles are tertiary, age-dependent skin changes.
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