Why Do Nasolabial Folds Appear? Exploring the Anatomical Perspectives and the Role of Thread-Based Interventions.

The classification of nasolabial folds into three types, each with distinct causative factors and mechanisms, is explored. Age-related changes in facial skin and connective tissues are examined in detail, revealing variations across different facial regions due to variances in tissue firmness and thickness. The innovative 'Reverse Technique,' involving cog threads to enhance tissue traction and effectiveness in thread-lifting procedures, is introduced. Detailed technical guidelines, anatomical considerations, and safety measures are provided, emphasizing the importance of identifying optimal vectors and fixing points to achieve maximum lifting effects while minimizing potential risks, particularly those associated with vascular structures. Additionally, the 'Cross Technique using volumizing thread' is discussed, designed to smooth tissue boundaries and rejuvenate sagging areas. Facial anatomy, including the positioning of arteries and ligaments, is underscored as essential for ensuring the safety and efficacy of procedures. In conclusion, this review stands as a comprehensive guide for practitioners, offering insights into innovative thread-lifting methods and their applications in addressing nasolabial folds. The primary focus is on achieving optimal aesthetic results while prioritizing patient safety.

Evaluation of the forAge Age-at-Death Estimation Program Using Pubic Symphyseal Surface in a Korean Population.

The forAge program estimates the age-at-death of human pubic symphysis using 3-dimensional scans. It was developed by Dennis E. Slice and Bridget F. B. Algee-Hewitt, and utilizes three distinct scores: the Slice and Algee-Hewitt (SAH) score, bending energy (BE), and ventral curvature (VC). However, these scores and age estimation regression equation were obtained through European American pubic symphysis. Changes in the pubic symphysis surface are evaluated as one of the most reliable indicators for estimating age, but in connection with this, using Korean materials, changes in the pubic symphysis surface and the actual changes are evaluated. There is no bar where the relationship between ages is grasped, and there are cases where a methodology developed for a specific group is applied to a Korean group. Changing the pubic symphysis surface by aging was evaluated as one of the most reliable indicators for estimating age. However, there is no study conducted on the relationship between changes in the pubic symphysis and actual age and applied the age estimation method for a specific population among Korean population. The purpose of this study is to compare the difference between the actual age and the estimated age in Korean to see if the forAge program is applicable to other population of different ancestral origin. One hundred and four modern Korean pubic symphyseal surfaces (47 to 96 years old) were used in this study. Through the pubic symphyseal surface 3-dimensional images, age-at-death was estimated via prediction equation and new regression lines using SAH, VC, and BE scores. Firstly, the estimated age via prediction equation using the first version of SAH score was lower than the actual age according to all pubic symphyseal surfaces for those older than 56. With aging, the difference between the actual age and estimated age became markedly larger. Secondly, the estimated ages via the new regression lines using VC, the second version of SAH score, and BE were shown a similar pattern to the previous prediction equation. The current study explored the applicability of a quantitative method using pubic symphyseal surface for age estimation in a modern Korean population. This study showed the forAge program cannot be applied to a modern Korean population, as they present relatively low correlations with the actual age-at-death.

A novel histologic description of the fibrous networks in the lid-cheek junction and infraorbital region.

The aim of this study was to identify the anatomical feature of retaining ligament and fat compartment on the lower eyelid and infraorbital region using a histological method, and to investigate clear definitions for them which could be used generally in the clinical area. Eighteen specimens from eight fresh Korean cadavers were stained with Masson trichrome or hematoxylin and eosin. The ligamentous and fascial fibrous tissue were clearly identified. The ligamentous fibrous tissue which traversed in the superficial and deep fat layer was skin ligament and orbicularis retaining ligament (ORL). The fascial fibrous tissue enclosed the orbicularis oculi muscle (OOc) and circumferencial adipose tissue. Based on the ligamentous and fascial structure, three fat compartments, septal, suborbicularis oculi and infraorbital fat compartment, could be identified. The OOc attached to orbital rim and dermis by ORL and skin ligament, and the muscle fascicle and fat fascicle provided the connection point to the ORL and skin ligament as enclosing all muscle and fat tissue. The combination of the force made by the skin ligament in the lower eyelid and ORL may decide the level and form of the infraorbital grooves.

Anatomical Considerations for the Injection of Botulinum Neurotoxin in Shoulder and Arm Contouring.

The utilization of botulinum neurotoxin in the field of body contouring is on the rise. Body contouring procedures typically focus on specific muscle groups such as the superior trapezius, deltoid, and lateral head of the triceps brachii. The authors propose identifying optimal injection sites for botulinum neurotoxin to achieve desired aesthetic contouring of the shoulders and arms. The authors conducted a modified Sihler's staining method on specimens of the superior trapezius, deltoid, and lateral head of the triceps brachii muscles, totaling 16, 14, and 16 specimens, respectively. The neural distribution exhibited the most extensive branching patterns within the horizontal section (between 1/5 and 2/5) and the vertical section (between 2/4 and 4/4) of the superior trapezius muscle. In the deltoid muscle, the areas between the anterior and posterior deltoid bellies, specifically within the range of the horizontal 1/3 to 2/3 lines, showed significant intramuscular arborization. Furthermore, the middle deltoid muscle displayed arborization patterns between 2/3 and the axillary line. Regarding the triceps brachii muscle, the lateral heads demonstrated arborization between 4/10 and 7/10. The authors recommend targeting these regions, where maximum arborization occurs, as the optimal and safest points for injecting botulinum toxin.

A novel description of the supporting system of the orbicularis oculi muscle in the infraorbital area: Tear trough muscle fiber.

BACKGROUND: The aim of this study was to elucidate the anatomical structures of supporting system of the infraorbital area. MATERIALS AND METHODS: Forty-four hemifaces from eleven Korean and eleven Thai cadavers were used to dissect the infraorbital area. Based on the dissection and previous histologic results, they were analyzed. RESULTS: The orbicularis oculi muscle (OOc) had two portions (palpebral and orbital portion) and four subparts (pretarsal, preseptal, prezygomatic, and premaxillary part). The elliptical muscle fiber of OOc was supported by circumferential connective tissue including skin ligament, orbicularis retaining ligament, zygomatic ligament, and zygomatic cutaneous ligament. The vertical muscle fiber, the tear trough muscle fiber, and medial muscular band directly attached to the skin. CONCLUSION: Full of subcutaneous tissue in the tear trough groove, strong attachment to the bone by tear trough ligament and to the skin by tear trough muscle fiber would multiply result in the tear trough on the face.

Anatomical consideration of ultrasonography-guided intraoral injection for temporal tendinitis.

Temporal tendinitis is characterized by acute inflammation often resulting from mechanical stress, such as repetitive jaw movements associated with jaw opening and closing and teeth clenching. Treatment for temporal tendinitis typically involves the administration of local anesthetic or corticosteroid injections. However, the complex anatomical structure of the coronoid process, to which the temporalis tendon attaches, located deep within the zygomatic arch, poses challenges for accurate injections. In this study, we aimed to establish guidelines for the safe and effective treatment of temporal tendinitis by using intraoral ultrasonography (US) to identify the anatomical structures surrounding the temporalis tendon and coronoid process. US was performed using an intraoral transducer on 58 volunteers without temporomandibular joint disease. The procedure involved placing the transducer below the occlusal plane of the maxillary second molar. Measurements were taken for the horizontal distance from the anterior border of the coronoid process, observed at the midpoint (MP) of the US images, and the depth of the coronoid process and temporalis muscle from the oral mucosa. The anterior border of the coronoid process was visualized on all US images and classified into three observed patterns at the MP: type A (anterior to the MP, 56.2%), type B (at the MP, 16.1%), and type C (posterior to the MP, 27.7%). The temporalis muscle was located at a mean depth of 3.12 ± 0.68 mm from the oral mucosa. The maxillary second molar is an intraoral landmark for visualizing the anterior border of the coronoid process. The new location information obtained using intraoral US could help identify the safest and most effective injection sites for the treatment of temporal tendinitis.

Three-dimensional micromorphology of human midpalatal suture and pterygomaxillary articular complex.

BACKGROUND: Sutures exist in the craniofacial area, and the pattern of maturation and synostosis of facial sutures is largely unknown. METHODS: For a comprehensive understanding of the three-dimensional circummaxillary suture micromorphology, human midpalatal suture (MPS) and pterygomaxillary articular complex from eight subjects' (five males, three females, 72-88 years old) autopsies were longitudinally scanned with microcomputed tomography. Additional histology was performed for hematoxylin and eosin staining. Sutural micromorphology was assessed by interdigitation index (II), obliteration index (OI) and obliteration number. Intergroup comparisons were performed with Kruskal-Wallis and Mann-Whitney U with Bonferroni correction (α = 0.005). Correlation with anteroposterior and craniocaudal gradients was assessed with Spearman's correlation test (α = 0.05). RESULTS: Maxillary region of MPS presented a higher II 1.50 (0.61) and obliteration number per slice 8 (9) (P < 0.005). OI was increased in palatomaxillary 35% (47%) followed by pterygopalatine suture 25% (49%) (P < 0.005). The II and OI of the MPS exhibited only a weak anteroposterior gradient, with relatively low correlations. Obliteration areas were found sporadically along the entire MPS. CONCLUSIONS: Based on these findings, it is conceivable that the success of nonsurgical maxillary expansion largely depends on individual variations in sutural morphology and maturation rather than appliance design.

Changes in masticatory performance during the retention period following 4-premolar extraction and non-extraction orthodontic treatment.

OBJECTIVES: To evaluate changes in masticatory performance (MP) during the retention period after extraction and non-extraction treatment and compare it with MP in individuals with normal occlusion. MATERIALS AND METHODS: Adult patients who had completed orthodontic fixed appliance treatment comprised the extraction and non-extraction treatment groups, and those with normal occlusion comprised the control group. Their mixing ability (MA), maximum bite force (MBF), and occlusal contact area (OCA) were recorded immediately after the fixed appliance was removed and at 1 month, 6 months, and 1 year post-treatment. The MA was measured via the two-color chewing gum MA test using ViewGum software, and the MBF and OCA were measured using Dental Prescale II system. RESULTS: MA immediately after orthodontic treatment was lower than that in the normal group but showed a time-dependent gradual increase during a 1-year retention period (P < 0.01). The MA at 1 month post-treatment was not significantly different between the three groups (P > 0.05). The MA revealed a significant correlation with the MBF and OCA (P < 0.01). CONCLUSIONS: The MP immediately after orthodontic treatment was lower than that in the normal group but increased gradually, with levels comparable to those of the normal occlusion group at 1 month post-treatment. Further, extraction did not affect the recovery of the MP after orthodontic treatment. CLINICAL RELEVANCE: No other study has evaluated the changes in MP during the retention period after orthodontic treatment. The findings show that compared with MBF and OCA, the patients' MP improved faster to levels found in normal occlusion.

Face painting as an anatomical learning tool based on individual ultrasonographic examination.

Considering the shift to online education during the COVID-19 pandemic, new and easily accessible educational videos and content on clinical anatomy are necessary. This study utilized numerous references and data on the anatomy of Asian facial muscles and blood vessels to accurately depict human anatomy through face painting. It aimed to provide clinicians accurate educational video content on anatomy to help prevent possible complications during noninvasive facial and surgical procedures. A 26-year-old Korean-Chinese male volunteer was used as a face painting model. The location of the blood vessels of the face was confirmed through ultrasonography images using a real-time two-dimensional B-mode. The model's face was painted by an artist majoring in anatomy. To reveal most anatomical structures on both sides of the face, the left side showed the structures observed when the skin and superficial fat layer are removed, and the right side revealed the deeper layer structures that can be seen when some muscles are cut. Fifteen superficial and deep muscles important in esthetic procedures were meticulously painted on the face. The face painting took a total of 6 h, and the video was edited to 5 min. This study merged the advantages of 2D and 3D by painting directly on the skin surface of a living model. Thus, it can provide more dynamic surface anatomy data. These contents inform clinicians about 3D anatomic location, which can help avoid complications when performing clinical procedures on the face.

Does the fixture thread depth affect the accuracy of implant placement during fully guided immediate implant placement?: A human cadaver study.

BACKGROUND: The fixture thread depth reportedly influences the primary stability of dental implant, but its effect on the positional accuracy in immediate implant placement has not been reported previously. MATERIALS AND METHODS: Fifty-six single-rooted, anterior and premolar teeth were extracted from six human cadavers, followed by installing either regular-threaded implants (RT group, N = 30) or deep-threaded implants (DT group, N = 26) completely relying on the surgical guide. Optical impressions taken after osteotomy and fixture installation were superimposed with the preoperative virtual planning data to measure the vertical, angular, platform and apex deviations that occurred during osteotomy and installation. RESULTS: While the osteotomy deviations were similar between the two groups, the angular and apex deviation of the DT group (2.67 ± 2.56°; 1.04 ± 0.49 mm, respectively) were significantly larger than those of the RT group (1.61 ± 1.04°; 0.67 ± 0.41 mm, respectively) during installation (p < .05). When the installation deviations were analysed in the anterior and premolar areas separately, the angular, platform and apex deviations of the DT group (3.05 ± 3.26°; 0.75 ± 0.32 mm; 1.08 ± 0.56 mm, respectively) were significantly larger than those of the RT group (1.56 ± 0.73°, 0.59 ± 0.28 mm; 0.62 ± 0.38 mm, respectively) in the anterior site (p < .05), whereas there was no significant intergroup difference in the premolar site. CONCLUSION: In immediate-implant surgery, using an implant with a deeper thread might increase the deviations during installation, especially in the anterior area.

The Deep Temporal Arteries: Anatomical Study with Application to Augmentations Procedures of the Temple.

The aim of this study was to determine the anatomical features of the deep temporal arteries (DTAs) and thereby provide clinical information for the temple augmentation procedure. Forty-two adult hemifaces from 15 Korean and 6 Thai cadavers (12 males, 9 females; mean age at death, 79.6 years) with no history of trauma or surgical procedure on the temple area were used for anatomical study. A detailed dissection was performed to identify the locations of the anterior and posterior deep temporal arteries (ADTA and PDTA) with reference to the vertical plane passing through the zygomatic tubercle. Fifty-eight healthy Korean participants (31 males and 27 females; mean age, 24.7 years) were included in the ultrasonographic study. The distance from the bone to the DTAs was measured at the level of the zygomatic tubercle (HZt ) and the eyebrow (HEb ). The DTAs were not found within 7.2-12.6 mm posterior to the zygomatic tubercle; instead, the locations varied widely at the HEb . The distances between the bone and the ADTA were 1.7 ± 1.2 mm (mean ± SD) and 1.3 ± 0.8 mm, and those between the bone and the PDTA were 2.1 ± 1.2 mm and 2.0 ± 1.4 mm at HZt and HEb , respectively. Our findings indicate that at HZt , the area 1 cm posterior to the zygomatic tubercle may be a safe area for deep temple augmentation procedures. However, because the distribution patterns of the DTAs at HEb and depth of the DTAs are variable, additional care is required to minimize the risks of the procedure.

A rare case of ligature strangulation using a dental unit: Distinguishing suicide from homicide in a death scene investigation.

Ligature strangulation is more common in homicides and is rarely seen in suicides and sexual asphyxia involving neck compression. We report a rare case of a dentist found dead of ligature strangulation next to a dental unit. The ligature was attached to the window frame, wrapped tightly around the neck once with a noose, and tied at the midpoint of the neck and at the head of the dental chair. A death scene and medicolegal investigation suggested suicidal ligature strangulation. The victim was squatting next to the dental unit with the control panel within reach. Pressing Button 1 (the recline button) would have tightened the ligature around the neck. A container containing pink nylon ribbon was found near the victim. The position of the knot at the front of the neck was consistent with suicide. Bloodstain pattern analysis confirmed the longitudinal flow pattern. No other remarkable findings were observed. Nobody had visited the clinic, autopsy found no drugs in his system, and the environment was undisturbed. Homicide was ruled out. According to witnesses, the victim had been in litigation with the owner of the building where his clinic was located. There were no reports of the victim having engaged in any unusual sexual or autoerotic activity. He had not received any death threats. Approximately 1 h before his death, he sent a suicide text message to his wife. Our case highlights the importance of distinguishing between suicide and homicide, especially in cases of ligature strangulation.

Ultrasonographic analyses of Crow's feet and novel guideline for botulinum toxin injection.

BACKGROUND: Crow's feet are bilateral orbital wrinkles formed by the orbital portion of the orbicularis oculi muscle, which is the target muscle for botulinum neurotoxin (BoNT) injection. OBJECTIVES: This study's aim was to demonstrate a novel BoNT injection guideline by assessing muscle width, thickness, and dynamic features using ultrasonography. METHODS: Twenty healthy Korean volunteers (10 men, 10 women; mean age, 25.6) participated. The width, thickness, and dynamic movement of the orbicularis oculi muscle were measured using ultrasonography. Two volunteers were selected to receive BoNT injections. Injections were administered using a novel method with two curved reference lines passing a point 15 mm lateral to the lateral canthus (conventional injection) and a point 5 mm lateral to the lateral margin of the frontal process of zygomatic bone (additional injection). RESULT: At the lateral canthus level, the distance between the lateral margin of the frontal process and the most lateral margin of the orbicularis oculi muscle was 12.5 ± 1.3 mm. The thickness of the orbicularis oculi muscle at the midpoint of the frontal process, the lateral marginal of the frontal process, and 5 mm lateral to the lateral marginal of the frontal process was 0.7 ± 0.3 mm, 1.1 ± 0.3 mm, and 1.2 ± 0.3 mm, respectively. The crow's feet of the two volunteers began to disappear from day 3 and completely disappeared on day 7 after the injection. CONCLUSION: The novel injection technique based on the ultrasonographic anatomy resulted in improvements in the appearance of crow's feet.

Clinical anatomy considerations on the muscular and vascular components of the midface by ultrasonographic imaging.

The first signs of face aging appear in the midface, so procedures such as botulinum toxin and filler injections are performed there. However, no guidelines based on clinical anatomy describing the muscular and vascular components in vivo have been published. The aim of this research was to describe the depths of the midface muscles and the locations of vessels using ultrasonographic (US) imaging. US was applied at 12 landmarks on the midface in 88 volunteers (49 males and 39 females; 19-36 years) to detect sex differences in the depths of muscles and the locations of the vessels. The depths of the orbicularis oculi (OOc), levator labii superioris alaeque nasi (LLSAN), and zygomaticus minor (Zmi) differed significantly with sex at P7 (p = 0.001) and P8 (p = 0.017), P1 (p = 0.028), and P4 (p = 0.035), respectively. The facial artery, facial vein, angular artery, angular vein, and perforator vessels were found at P9, P2 and P10, P1, P1 and P5, and P8, P11 and P12, respectively. The findings indicate that the depths of the OOc, LLSAN, and Zmi muscles differ between the sexes and that the vessels appear at specific landmarks. This information could help in developing anatomical guidelines for several procedures.

Three-dimensional topography of facial soft tissues for the safer and effective threading procedures.

INTRODUCTION: To reduce complications caused by the procedure, the target layer for thread lifting should be the superficial fat or superficial musculoaponeurotic system of the face. The aim of this study was to establish the thicknesses of the facial skin and superficial fat using a 3D scanning system to provide basic clinical data for thread lifting. MATERIAL AND METHODS: Thirty fixed Korean and Thai cadavers (male: 17, female: 13) were used. The depths of the skin and superficial fat were measured using a three dimensional (3D) structured-light scanner. Facial images of both undissected and removed skin and superficial fat were taken with the 3D scanner. The paths from the temple and the front of the tragus to the infraorbital, perioral, cheek, and mental areas were displayed on the 3D image. The thickness along the path was measured by calculating the difference between the undissected and dissected 3D images. RESULTS: The means and standard deviations of thicknesses of the skin and superficial fat were 2.1 ± 0.4 mm and 5.2 ± 1.9 mm in the 11 pathways. The facial skin became thicker going toward the lower aspect of the face from temple to infraorbtial and perioral regions. The thickness of the superficial fat around the marionette line showed the biggest change. CONCLUSIONS: The present findings indicate that a 3D scanning system can yield crucial anatomical information about the thickness of the facial skin and superficial fat for use in various minimally invasive clinical procedures including thread lifting.

Body donation trends in Yonsei University: a statistical analysis of donor records.

Body donation trends in Korea have changed significantly over the last 3 decades. Establishing a body donation system will promote donations to universities for academic purposes. Yonsei University College of Medicine started its own body donation system in 1992, including documenting donors' records. However, there has been no reported attempt to analyze the trend of these records, which could provide noteworthy information that can be interpreted for medical advances. This study performed a statistical analysis of the donors' records between 1992 and 2019 to analyze the sociological and anthropological changes. Donor personal information such as sex, age, religion, and place and cause of death were extracted from the Yonsei University College of Medicine database. Our statistical analysis revealed significant correlations between donors' records and the changes in the number of geriatric hospitals, religious beliefs, number of donations, and donor age.

Effective Locations for Injecting Botulinum Toxin into the Mentalis Muscle; Cadaveric and Ultrasonographic Study.

The mentalis muscle is now considered key structures when performing procedures for rejuvenating the lower face. The aim of this study was to determine the anatomical morphology and location of the mentalis muscle and thereby provide anatomical information for facilitating clinical procedures designed to rejuvenate the lower face. Forty-four adult hemifaces from five Thai cadavers and 21 Korean cadavers were dissected to identify the locations of the mentalis muscle. Sixty-six hemifaces from 33 healthy young Korean subjects were included in an ultrasonographic study. The depth of the mentalis muscle below the skin surface, the thickness of the mentalis muscle, and the distance from the bone to the mentalis muscle were measured at the two points that were 5 mm lateral to the most-prominent point of the chin. The mentalis muscle was classified into two types based to its shape: in type A (86.4%, 38 of the 44 cases) it was dome shaped in three dimensions, while in type B (13.6%, 6 of the 44 cases) it was flat. The mentalis muscle was present mostly at the area 5-10 mm from the midsagittal line and 20-30 mm from a horizontal line connecting the mouth corners. The mentalis muscle was present between depths of 6.7 to 10.7 mm below the skin. This new information about the location of the mentalis muscle may help when identifying the most effective and safe botulinum toxin injection points and depths during esthetic procedures for weakened facial rhytides on the lower face.

Anatomical Injection Guidelines for Glabellar Frown Lines Based on Ultrasonographic Evaluation.

When botulinum neurotoxin (BoNT) is injected to treat glabellar frown lines, the corrugator supercilia muscle (CSM) and procerus muscles are the main targets. Although there have been many studies on the treatment of glabellar frown lines, no study has confirmed the dynamic movement under ultrasonography (US). This study examined and evaluated dynamic muscle movements under US, thereby providing more effective BoNT injection guidelines for glabellar frowning. Glabellar frowning was categorized as either Type A or B. Type A is the general frowning pattern in which vertical wrinkles are made by contracting the CSM and procerus muscles (81%, n = 13). On US images, the procerus muscle thickens and the bilateral CSMs contract. Type B is an upward frowning pattern demonstrating upward elevation of vertical wrinkles due to hyperactive contraction of the frontalis muscle during frowning (19%, n = 3). On US images, the hypoechoic frontalis muscle thickens, forming horizontal forehead lines. After BoNT injection into the CSM and frontalis muscle but not the procerus muscle, Type B patterns showed improvements in the vertical crease and horizontal forehead line. Both types showed improvement in glabellar frown lines after conventional injection, but the horizontal forehead line did not improve in Type B. Type B wrinkles improved after additional injections into the frontalis muscle. This study provided novel anatomical findings related to the injection of glabellar frown lines with BoNT. Preliminary analysis and optimized procedures using US will enable more effective and safer injections.

Three-Dimensional Evaluation of the Depressor Anguli Oris and Depressor Labii Inferioris for Botulinum Toxin Injections.

BACKGROUND: Botulinum toxin type A (BoNT-A) injection administered at an inappropriate site or depth can produce an unwanted change in facial animation because the depressor anguli oris (DAO) and depressor labii inferioris (DLI) muscles are partially overlapped. Therefore, simple BoNT-A injection guidelines, based on 3-dimensional (3D) facial anatomic references and landmarks, would be very useful. OBJECTIVES: The aim of this study was to establish novel BoNT-A injection guidelines that include the soft tissue thickness at the lower perioral region. Data were acquired with a 3D scanning system combined with dissections in order to obtain accurate injection sites and depths for the DAO and DLI. METHODS: 3D scans of the facial skin, superficial fat, and facial muscle surface were performed in 45 embalmed cadavers. The thicknesses of the skin and subcutaneous layer were calculated automatically from superimposed images at each of 5 reference points (P) in the perioral region. RESULTS: In every case (100%), P3 and P5 were located in the DLI and DAO areas, respectively (45/45). Therefore, we defined P3 as the "DLI point" and P5 as the "DAO point." The soft tissue thicknesses at the DLI and DAO points were 6.4 [1.7] mm and 6.7 [1.8] mm, respectively. CONCLUSIONS: The P3 and P5 described in this study are effective guidelines that only target the DLI and DAO. Clinicians, specifically, can easily use facial landmarks, such as the cheilion and pupil, to assign the DLI and DAO points without any measurement or palpation of the modiolus.

Ultrasonography Analysis of Vessels Around the Forehead Midline.

BACKGROUND: Filler injection into the glabella is well known to be a highly dangerous procedure due to the high risk of embolism and intravascular injection. Although it is conventional practice to insert the cannula into the middle of the forehead to perform injections into the glabella or radix, vascular structures can be observed in this region during anatomic dissection procedures. OBJECTIVES: The aim of this study was to characterize the blood vessels around the forehead midline in order to provide crucial anatomic information for ensuring the safety of noninvasive procedures involving the forehead and glabella. METHODS: Ultrasonography image scanning was performed at the following 4 points on the forehead midline: trichion (P1), metopion (P2), halfway point between metopion and glabella (P3), and glabella (P4). The courses and locations of vessels were identified and classified according to their proximity to the forehead midline. RESULTS: Vessels coursing within 0.75 cm either side of the forehead midline were found in 34% to 50% of individuals. Arteries running near the forehead midline tended to be dominant on the right side of the forehead except in the P4 area. About half of the individuals had vessels in the P4 area, of which 96.7% were veins. CONCLUSIONS: The present results indicate that there are superficial vessels running close to the midline of the forehead. This anatomic information can explain the higher incidence of vascular complications during conventional aesthetic procedures. To ensure safety, the cannula entry point or needle puncture point for glabella augmentation should be reconsidered.