Naming of parts: a presentation of facial surface anatomical terms

Distribution of the Laterally Supplying Facial Nerve to the Orbicularis Oculi Muscle

BACKGROUND

The facial nerve that traverses the lateral border of the orbicularis oculi muscle is considered the primary motor for the muscle. Nevertheless, the lateral motor supply to the orbicularis oculi muscle has not yet been fully described.

OBJECTIVES

The aim of this study was to report detailed anatomic information about the lateral motor supply route to the orbicularis oculi.

METHODS

Facial nerve branches that cross the lateral orbicularis oculi border were fully traced from the parotid border to the nerve destinations in 43 fresh hemifaces by microscopic surgical dissection and time-lapse photography.

RESULTS

Through the lateral route, the anterior temporal and upper zygomatic branches supply the superior orbital and superior preseptal orbicularis oculi of the upper eyelid, as well as the lateral pretarsal and malar orbicularis oculi, excluding the upper medial pretarsal portion of the upper eyelid and most of the lower eyelid. The nerve supplying the lateral pretarsal orbicularis oculi muscle crosses the anterior area of the zygomatic arch. It then traverses an area 6 mm above and 4 mm below the lateral canthal crease.

CONCLUSIONS

The anterior area of the zygomatic arch and an area 6 mm above and 4 mm below the lateral canthal crease are the facial nerve danger zones. The present anatomic findings provide surgeons with further insights for performing blepharoplasty, midface lift, facelift, and facial nerve reconstructive surgery.

Facial fold and crease development: A new morphological approach and classification

Facial folds and creases are established descriptive anatomical terms for structures of which the morphological characteristics and origins are not clearly defined. The aim of this study was to perform a morphological investigation of the nasolabial fold (NLF), mandibular fold (MF), deep transverse forehead (DTFC), infraorbital fold (IOF) and upper eyelid fold (UEF), correlating their phenotypes to differences in the superficial musculoaponeurotic system (SMAS), noting morphological differences and similarities. Full-graft tissue blocks of skin, subcutaneous tissue, and mimic muscles collected postmortem were studied histologically. Serial histological sections were stained with Azan. Location- and composition-specific morphological differences were determined. Histological serial section digitalization and three-dimensional reconstruction of the tissue blocks were performed. Three different types of SMAS architecture were identified. Type I SMAS consisted of parallel-aligned fibrous septa connecting the mimic muscles to the skin that covered the cheek, infraorbital and supraorbital, and forehead areas. Type II SMAS morphology appeared as a condensed Type I SMAS architecture with stronger fibrous septa and smaller fatty tissue compartments covering the lower and upper lip areas. Type III SMAS consisted of loose connective tissue covering the lower and upper eyelid regions. NLF, MF, IOF, and UEF are habitual primary folds induced by morphological changes in the underlying SMAS architecture. The secondary, accidental creases (DTFC) are cutaneous depressions derived from interacting dermal-skeletal-muscular changes without SMAS structure changes. The upper and lower eyelid wrinkles were tertiary, age-related undulating skin redundancy formations. Clin. Anat. 32:573-584, 2019. © 2019 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists.

Categorizing facial creases: A review

Ensuring uniformity in the nomenclature standardization of facial creases is important to enable the scholarly community to follow and debate the advancements in research. This review highlights the prevailing disparity in the nomenclature that refers to the same facial crease by researchers and laypeople, and suggests uniform names for the facial creases based on available literature. The previous and current trends in facial crease classification are also discussed. The nomenclature of the facial creases considered for this review include the following: the nasolabial fold, corner of the mouth lines, upper and lower lip creases around the mouth region, the mandibular folds, the bifid nose, the transverse nasal line, the vertical glabellar line, chin crease, the mental crease, four type of creases around the eyes, forehead creases, and periauricular creases. A figure illustrating the above facial creases is included as reference. It is hoped that the proposed standardization of nomenclature would ensure a more scientific referencing of facial creases enabling more effective scientific interaction among the scholarly community as well as the laypeople interested in the research and application of facial creases.

The post-mortem resilience of facial creases and the possibility for use in identification of the dead

The post-mortem resilience of facial creases was studied using donated bodies in order to establish the efficacy of crease analysis for identification of the dead. Creases were studied on normal (pre-embalmed) and bloated (embalmed) cadavers at the Centre for Anatomy and Human Identification (CAHID) to establish whether facial bloating would affect facial crease visibility. Embalming was chosen to simulate the effects produced by post-mortem bloating. The results suggested that creases are resilient and changes were only detected for creases located on the periphery of the face, particularly at areas where the skin is thick, such as at the cheeks. Two new creases not previously classified were identified; these creases were called the vertical superciliary arch line and the lateral nose crease. This research suggests that facial creases may be resilient enough after death to be utilised for human identification.

The superficial temporal fat pad and its ramifications for temporalis muscle construction in facial approximation

The construction of the facial muscles (particularly those of mastication) is generally thought to enhance the accuracy of facial approximation methods because they increase attention paid to face anatomy. However, the lack of consideration for non-muscular structures of the face when using these "anatomical" methods ironically forces one of the two large masticatory muscles to be exaggerated beyond reality. To demonstrate and resolve this issue the temporal region of nineteen caucasoid human cadavers (10 females, 9 males; mean age=84 years, s=9 years, range=58-97 years) were investigated. Soft tissue depths were measured at regular intervals across the temporal fossa in 10 cadavers, and the thickness of the muscle and fat components quantified in nine other cadavers. The measurements indicated that the temporalis muscle generally accounts for <50% of the total soft tissue depth, and does not fill the entirety of the fossa (as generally known in the anatomical literature, but not as followed in facial approximation practice). In addition, a soft tissue bulge was consistently observed in the anteroinferior portion of the temporal fossa (as also evident in younger individuals), and during dissection, this bulge was found to closely correspond to the superficial temporal fat pad (STFP). Thus, the facial surface does not follow a simple undulating curve of the temporalis muscle as currently undertaken in facial approximation methods. New metric-based facial approximation guidelines are presented to facilitate accurate construction of the STFP and the temporalis muscle for future facial approximation casework. This study warrants further investigations of the temporalis muscle and the STFP in younger age groups and demonstrates that untested facial approximation guidelines, including those propounded to be anatomical, should be cautiously regarded.