Lip Sonoanatomy and Relevance to Aesthetic Filler Injections: A Pictorial Review

Background: Lips are central to facial aesthetics, influencing overall balance and harmony. Ultrasound has become a key tool for assessing lip musculature and neurovascular structures, particularly in aesthetic filler injections. By enhancing precision and safety, ultrasound is valuable in procedures addressing age-related lip changes, yet standardized scanning protocols remain underexplored. Aims: This review examined lip anatomy, summarized ultrasound applications in aesthetic procedures, introduced a structured scanning protocol, and highlighted its role in guiding filler injections. Methods: A systematic search of PubMed, Scopus, Embase, and Web of Science was conducted up to August 1, 2024, using keywords related to ultrasound and lip anatomy. Studies involving human subjects or cadavers using ultrasound for lip assessment and injection guidance were included, whereas nonhuman studies, alternative imaging methods, and research unrelated to the lip region were excluded. Six studies met the criteria. Results: Ultrasound improves precision in lip injections by identifying key structures, including the superior and inferior labial arteries and the orbicularis oris muscle, reducing vascular risks. A structured scanning approach enhances procedural safety and efficacy. Conclusions: Ultrasound is a valuable tool in aesthetic lip procedures, improving accuracy and minimizing complications. Further research is needed to refine protocols and establish ultrasound as a standard practice in lip augmentation.