### Ultrasound Diagnostics in Aesthetic Surgery of the Face and Neck  
Age-related changes in the face and neck are characterized by an excess and accompanied by the ptosis of healthy soft tissues. The severity of these changes determines the choice of correction method and affects the postoperative result. To evaluate and compare the results of surgical correction, plastic surgeons mainly rely on the examination, palpatory displacement of tissues, their own experience and knowledge (which all are subjective), and photos and videos in the pre- and postoperative period, which only provide an idea of the external contours of the face and neck. However, this is clearly not sufficient for an objective assessment of the condition of soft tissues or to determine the degree of participation of each tissue in the formation of deformation [64; 65; 66; 67]. Aging of the face and neck is caused by involutive changes in the condition of the skin, muscles, and adipose tissue [68]. In the neck area, age-related changes can be determined by weakness of the skin and platysma, the appearance of visible platysma strands, the ptosis of the submandibular glands, lipodystrophy or local increased accumulations of adipose tissue, and even jaw resorption [69]. With the most pronounced age-related changes in the anatomy of the face and neck, surgical techniques have become more complex and traumatic, which increases the duration of rehabilitation and the risks of complications [70]. Despite the obvious importance of an accurate assessment of the causes of age-related changes in the contours of the cervical-facial region, surgeons often neglect the use of additional objective diagnostic methods. An analysis of the literature shows that only a few works have been devoted to the objective diagnosis of the causes of involutional changes in the soft tissues of the face and neck [71]. Unfortunately, almost all authors have relied on a subjective assessment of the clinical situation. At the same time, based on the growing number of anatomical studies [72], the increasing role of preoperative diagnostics in planning methods of the surgical correction of age-related changes in the soft tissues of the face and neck becomes obvious. B-mode ultrasound is one of the most accessible non-invasive methods of diagnostics [73]. Despite this, ultrasound is not used in the clinical practice of plastic surgeons to diagnose age-related changes. There is also limited research on the ultrasound anatomy. Ultrasound diagnostic specialists do not focus on these surface layers of soft tissues, and they often go unnoticed during ultrasound studies for other head and neck diseases and are not included in research protocols. However, the growing demand for aesthetic procedures, and often for minimally invasive surgery with a short rehabilitation period, has made its own adjustments to the practical activities of plastic surgeons. The important role of ultrasound in the diagnostics of age-related changes in the face and neck was evaluated over the course of our research. The results of studies conducted using transducers of different imaging depths (9-24 MHz) were compared, thereby determining the informativeness and validity of their use in aesthetic surgery. One of the important nuances during the study is the vertical position of the patient's head and neck, since during the change in body position, soft tissues of the face and neck are displaced. The maximum gravitational age-related displacement of soft tissues occurs in the vertical position, which determines that the patient is in an upright position during the examination. Therefore, ultrasound in this position is able to show an objective picture of the participation of various tissues (skin, subcutaneous and subplatysmal fat, muscles, submandibular salivary glands) in the patient's age-related contour deformities. _Clinical case #1_.