Revisiting the Deep Fatty and Fascial Layers Between the Temple and the Midface: An Ultrasound-based Investigation

BACKGROUND: Recent ultrasonography findings suggest that temporal and midfacial layers are anatomically and functionally connected. Understanding this continuity is important for safe and effective surgical and minimally invasive procedures. OBJECTIVES: This study aimed to identify and characterize the continuity of deep fatty and fascial layers between the temples and midface in treatment-naïve adults. METHODS: A single-center, cross-sectional observational study was conducted in 40 healthy volunteers using standardized bilateral facial ultrasonography with a 20-MHz linear probe. Four vertical and two oblique transducer positions were used to assess continuity between the temporal and midfacial regions. RESULTS: Ultrasound imaging provided excellent visualization of the investigated fascial and fatty layers. Fat located between the deep fascial layers of the temple and within the intermediate temporal fat pad transitioned from a multilaminar configuration to a unilaminar pattern as it crosses the zygoma, extending to a continuous multilaminar arrangement in the lateral and medial midface. Dense fascial boundaries in the preauricular region limited lateral extension, while anterior boundaries were formed by the zygomaticus major and minor muscles and associated ligaments. Results were confirmed by a second ultrasound examiner, 3 body donors and histology. CONCLUSIONS: Continuous anatomical pathways connect the deep temporal and deep midfacial fatty and fascial layers. These findings non-invasively confirm previous clinical observations and help explain filler spread following midfacial and temporal interventions.