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 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.

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.

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.

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.

Sonographic Analysis of the Upper Labial Orbicularis Oris and Its Clinical Implications.

BACKGROUND: Purse string lips, which include the vertical wrinkles over the lips, are frequently observed in aged individuals. Botulinum toxin and fillers are routinely injected into these areas to remove the wrinkles; however, the anatomy of the orbicularis oris muscle (OOr) near the vermilion border area has not been well defined. OBJECTIVES: The aim of this study was therefore to identify any morphological differences of the upper OOr via sonographic imaging. METHODS: The upper lip muscles as observed utilizing an ultrasound device were divided into 2 muscles (pars peripheralis and pars marginalis) that were subsequently divided into a further 2 types (Type I and Type II) associated with the development of the pars marginalis. Type II was further divided into Type IIa and Type IIb depending on whether the muscle fibers were well developed and connected. RESULTS: On the midline of the lip, Type I, in which the pars marginalis was rarely observed and only appeared in traces, was observed in 20.0% of the volunteers. Type IIa, in which the pars marginalis was well-developed and appeared continuous, was observed in 42.9% of the volunteers. Type IIb, in which the pars marginalis was observed but appeared discontinuous, was observed in 37.1% of the volunteers. CONCLUSIONS: The shapes of the upper pars marginalis of the OOr varied markedly between volunteers. Type classification of the OOr based on its shape and the lip appearance serves as a reliable source of reference information to be utilized when injecting botulinum toxin into the upper lip.

Regional thickness of facial skin and superficial fat: Application to the minimally invasive procedures.

Various recently introduced minimally invasive treatment modalities are now widely used for enhancing the aging face. In a special, filler is used to increase the volume of tissue, and so understanding the regional thickness and distribution of the facial superficial fat is essential for optimizing minimally invasive procedures. The aim of this study was to establish the overall facial skin and superficial fat thicknesses using a three-dimensional (3D) scanning system. From 53 adult Korean and Thai embalmed adult cadavers, the undissected and serially-dissected facial specimens were scanned and reconstructed. The facial skin and superficial fat thicknesses on seven facial regions were calculated from the superimposed images. The facial skin tended to become thicker in the order of the radix and dorsum, and the temple, supraorbital, forehead, perioral, cheek, and infraorbital areas. The skin was thinnest at radix and dorsum (1.51 ± 0.55 mm), and thickest in infraorbital region (1.97 ± 0.84 mm). The facial superficial fat thickness tended to increase in the order of the radix and dorsum, supraorbital, forehead, temple, cheek, infraorbital, and perioral regions. The superficial fat was thinnest at the radix and dorsum (1.61 ± 1.07 mm), and thickest in the perioral region (5.14 ± 3.31 mm). The facial superficial fat thickness tended to increase in the order of the radix and dorsum, supraorbital, forehead, temple, cheek, infraorbital, and perioral regions. The present findings indicate that 3D scanning system can yield crucial anatomical information about depths of the facial skin and superficial fat layers for utilization in various clinical procedures. Clin. Anat. 32:1008-1018, 2019. © 2019 Wiley Periodicals, Inc.

Positional relationship between the pectoralis major and external abdominal oblique muscles for consideration during dual-plane breast augmentation.

During dual plane breast augmentation (DPBA), the costal origin of the pectoralis major (the PM) should be cut to ensure appropriate coverage and positioning of an implant. However, surgeons sometimes make inappropriate planar incisions and insufficient muscular incisions because the external abdominal oblique (the EAO) muscle partially overlaps the lateral portion of the PM. The goal of this study was to clarify the positional relationship between the PM and EAO with the aim of improving the accuracy of implant and muscular incisions during DPBA. Forty sides of 20 embalmed and fresh cadavers were dissected. The midline and midclavicular line (MCL) were used as reference lines for measurements. We clarified the overlapping patterns between the PM and EAO, and measured the distances from the MCL to the borders of those two muscles. The costal part of the PM originated from the 5th (25%), 6th (70%), or 7th rib (5%), respectively. The distances from the MCL to the lateral border of the PM at the 4th, 5th, and 6th ribs were 49.8 mm, 30.5 mm, and 6.3 mm, respectively. In 90% of the specimens, the PM and the EAO overlapped near the MCL. The width of the overlapping portion between the PM and EAO was about 25 mm. This study is one of the first to suggest an innovative approach for explaining the positional relationships between the PM and EAO. Our findings can be useful for surgeons attempting to produce optimal outcomes in DPBA, especially in procedures that involve patients of different races. Clin. Anat. 31:339-346, 2018. © 2018 Wiley Periodicals, Inc.

Classification of unusual insertion of the pectoralis minor muscle.

PURPOSE: The pectoralis minor muscle (PMi) generally originates from the third, fourth, and fifth ribs and inserts on the medial and superior margins of the anterior portion of the coracoid process. Variations in the shape and attachment point of the PMi could cause discomfort in the shoulders. The aim of this study was to observe the types of morphological insertion patterns and attachment sites of the PMi. METHODS: Seventy-four sides of fresh, embalmed Korean (42 sides; mean age 78 years) and Thai (32 sides; mean age 78 years) cadavers were dissected to analyze the morphological insertion types and attachment sites of the PMi. RESULTS: Unusual insertion patterns were evident in about 23% of the samples. When the portion of the PMi tendon ran over the coracoid process, the most common attachment site was the glenohumeral joint capsule. We also confirmed the attachment of the PMi to the clavicle. Costal attachments of the PMi that extend from the second rib to the fourth rib were observed frequently as well. CONCLUSIONS: Unusual insertion patterns of the PMi are common. Some authors consider that tendon attachment to the joint capsule can cause shoulder pain. In addition, the PMi tendon could be utilized in acromioclavicular joint reconstruction. Surgeons need to be aware of the possibility of a PMi variant being found during surgery even when this is not visible in magnetic resonance or ultrasound imaging.

Anatomy of the lateral femoral cutaneous nerve relevant to clinical findings in meralgia paresthetica.

INTRODUCTION: Compression of the lateral femoral cutaneous nerve (LFCN), known as meralgia paresthetica (MP), is common. We investigated the topographic anatomy of the LFCN focusing on the inguinal ligament and adjacent structures. METHODS: Distances from various bony and soft-tissue landmarks to the LFCN were investigated in 33 formalin-embalmed cadavers. RESULTS: The mean distance from the anterior superior iliac spine (ASIS) to the LFCN was 8.8 mm. In approximately 90% of cases, the LFCN lay <2 cm from the medial tip of the ASIS, whereas, in 76% of cases, it was <1 cm away. The mean angle between the inguinal ligament and LFCN was 83.3°. CONCLUSIONS: We determined the variability of the location of the LFCN at the boundary between the pelvic and femoral portions. The reported results will be helpful for diagnosis and treatment of MP. Muscle Nerve 55: 646-650, 2017.

Three-Dimensional Topography of the Supratrochlear Nerve With Reference to the Lacrimal Caruncle, and Its Danger Zone in Asians.

BACKGROUND: The supratrochlear nerve (STN) is relatively superficial and therefore vulnerable to iatrogenic injury. OBJECTIVE: To elucidate the course of STN with reference to the lacrimal caruncle, with the aim of preventing nerve injury during surgery in the forehead region. MATERIALS AND METHODS: Thirty-four hemifaces from 18 Korean cadavers were dissected. The vertical line through the apex of lacrimal caruncle and the horizontal line through the supraorbital margin were used as horizontal and vertical reference lines, respectively. The course of STN in the frontal view and the point at which it pierced the overlaying musculature were examined. RESULTS: After exiting the corrugator muscle cushion, the STN enters the subcutaneous plane by piercing the frontalis muscle. These piercing points occurred at mean horizontal and vertical distances relative to the medial branch of the STN of 9.2 and 9.6 mm, respectively; the corresponding distances for the lateral branch of the STN were 1.1 and 15.3 mm, respectively. CONCLUSION: When performing surgery in the medial forehead region, the surgeon must ensure that the dissection plane of forehead tissue is more superficial: superiorly within 1.5 cm from the supraorbital margin and medially within 1.0 cm from the vertical line through the apex of lacrimal caruncle.

Validity and reliability of a structured-light 3D scanner and an ultrasound imaging system for measurements of facial skin thickness.

Three-dimensional (3 D)-scanning-based morphological studies of the face are commonly included in various clinical procedures. This study evaluated validity and reliability of a 3 D scanning system by comparing the ultrasound (US) imaging system versus the direct measurement of facial skin. The facial skin thickness at 19 landmarks was measured using the three different methods in 10 embalmed adult Korean cadavers. Skin thickness was first measured using the ultrasound device, then 3 D scanning of the facial skin surface was performed. After the skin on the left half of face was gently dissected, deviating slightly right of the midline, to separate it from the subcutaneous layer, and the harvested facial skin's thickness was measured directly using neck calipers. The dissected specimen was then scanned again, then the scanned images of undissected and dissected faces were superimposed using Morpheus Plastic Solution (version 3.0) software. Finally, the facial skin thickness was calculated from the superimposed images. The ICC value for the correlations between the 3 D scanning system and direct measurement showed excellent reliability (0.849, 95% confidence interval = 0.799-0.887). Bland-Altman analysis showed a good level of agreement between the 3 D scanning system and direct measurement (bias = 0.49 ± 0.49 mm, mean±SD). These results demonstrate that the 3 D scanning system precisely reflects structural changes before and after skin dissection. Therefore, an in-depth morphological study using this 3 D scanning system could provide depth data about the main anatomical structures of face, thereby providing crucial anatomical knowledge for utilization in various clinical applications. Clin. Anat. 30:878-886, 2017. © 2017 Wiley Periodicals, Inc.

Emerging Points of the Supraorbital and Supratrochlear Nerves in the Supraorbital Margin With Reference to the Lacrimal Caruncle: Implications for Regional Nerve Block in Upper Eyelid and Dermatologic Surgery.

BACKGROUND: Blocking the supraorbital nerve (SON) and supratrochlear nerve (STN) by injecting anesthetic distal to the surgical site has the advantage in upper eyelid surgery that avoids obscuring the surgical landmarks and compromising the levator function. OBJECTIVE: To identify the emerging points of the SON and STN in the supraorbital margin with reference to the lacrimal caruncle. METHODS: Forty-nine orbits from 27 embalmed Korean cadavers were dissected. The lacrimal caruncle and facial midline were used as landmarks. The emerging points of the SON and STN in the supraorbital margin were determined. RESULTS: The emerging points of the SON and STN were, respectively, located at 3.0 mm lateral and 3.3 mm medial to the vertical line through the apex of the lacrimal caruncle along the supraorbital margin. The horizontal distances from the facial midline to the emerging points of the SON and STN were 22.8 and 15.2 mm, respectively. CONCLUSION: The optimum sites for achieving SON and STN block are, respectively, located approximately 3 mm lateral and 3 mm medial to the vertical line through the apex of lacrimal caruncle along the supraorbital margin. This knowledge will help the surgeon achieve an easy and accurate approach for regional nerve block.

Positional Relationship of Ethmoidal Foramens With Reference to the Nasion and Its Significance in Orbital Surgery.

PURPOSE: The aim of the study was to elucidate the positional relationship of the ethmoidal foramens (EFs) with reference to the nasion to facilitate prediction of the exact location of EFs, the optic canal (OC), and the frontoethmoidal suture (FS), and thereby avoid complications during complex surgery involving the medial wall of the orbit. MATERIALS AND METHODS: One hundred two intact orbits of 57 embalmed cadavers were dissected in this observational anatomic study. Nasion' (N') was defined as the intersection point of the medial orbit margin with the horizontal line through the nasion, and this was used as a reference point. N'-OC was defined as the straight line joining N' and OC. The locations of the anterior ethmoidal foramen (AEF), posterior ethmoidal foramen (PEF), and OC were determined with reference to N'. The vertical distances from N'-OC to EFs and to FS were also determined. RESULTS: The N'-AEF, AEF-PEF, and PEF-OC distances were 18.4, 15.3, and 8.3 mm, respectively. Vertically, AEF and PEF were situated at 0.2 mm below and 0.4 mm above N'-OC, respectively. At the same reference points, N'-OC was situated at 0.4 and 0.6 mm above FS, respectively. CONCLUSIONS: N', AEF, PEF, and OC were considered to be situated on the same straight line, and N'-OC could be regarded as coinciding with FS. This means that N' is an easily identifiable and reliable landmark for identifying EFs, OC, and FS. Our navigational parameters with reference to N' will help surgeons to enhance the safety of orbital surgery.

Anatomy of facial and trigeminal nerve branches associated with the corrugator supercilii muscle: microdissection and modified Sihler staining.

BACKGROUND: Deactivation of the corrugator supercilii for the treatment of unintentional glabellar lines requires high selectivity to avoid sensory complications. OBJECTIVE: The aim of this study was to delineate the topographic anatomy of facial and trigeminal nerves in relation to the corrugator supercilii to improve the selectivity and safety of deactivation of the corrugator supercilii muscle. MATERIALS AND METHODS: The number, courses, and attachments of the facial nerve to the corrugator supercilii muscle were investigated by dissection of 27 cadaveric hemifaces. Twelve cadaveric hemiforehead flaps were stained using a modified Sihler method to trace the supraorbital and supratrochlear branches. RESULTS: On average, 1.8 branches of the facial nerve at the zygomatic arch were associated with the corrugator supercilii muscle through 1 (29.3%) or 2 terminal rami (70.7%). The trigeminal nerve gave off 7.7 supraorbital and 5.1 supratrochlear branches emerging from orbit. The majority of the supraorbital branches became intramuscular branches (60.4%), whereas the majority of the supratrochlear branches became superficial branches (67.8%). CONCLUSION: Resection of the muscle may damage the intramuscular trigeminal branches, leading to sensory changes. The course of the facial nerve branches to the corrugator supercilii muscle was much more predictable at their distal part than the proximal part.

Multiple muscular variations in the neck, upper extremity, and lower extremity biased toward the left side of a single cadaver.

Although numerous reports have found accessory or supernumerary muscles throughout the human body, multiple appearances of these variations biased toward one side of body are rare. We report a 76-yr-old male cadaver with an accessory head of the biceps brachii and palmaris profundus, and a muscular slip between the biceps femoris and semitendinosus on the left side in addition to a bilateral accessory belly of the digastric muscle. No remarkable nervous, vascular, or visceral variation accompanied these variations. An interruption of normal somitogenesis or myogenesis may be a cause of these variations.

New insights into the origin of the lumbrical muscles of the foot: tendinous slip of the flexor hallucis longus muscle.

PURPOSE: The aim of this study was to clarify the origins of the lumbricals of the foot toward a better understanding of its precise action in the gait. METHODS: The lumbricals in the foot were investigated in 66 specimens of embalmed Korean adult cadavers. RESULTS: The first lumbrical arose as two muscle bellies from both the tendon of the FDL and the tendinous slip of the FHL in 83.3 %, and as one muscle belly from the tendon of the FDL or the tendinous slip of the FHL in 16.7 %. These two muscle bellies subsequently merged to form the muscle belly of the first lumbrical. The second lumbrical arose from the tendinous slips of the FHL for the second and third toes as well as the tendon of the FDL in all specimens. The third lumbrical arose from the tendinous slips of the FHL for the third and fourth toes in 69.7 %, and the fourth lumbrical arose from the tendinous slip of the FHL for the fourth toe in 18.2 %. Some deep muscle fibers of the fourth lumbrical arose from the tendinous slip of the FHL for the second toe in 4.5 %, for the third toe in 28.8 %, and for the fourth toe in 15.2 %. CONCLUSIONS: The results of this study constitute new anatomical knowledge regarding the origin of the lumbricals, and provide insight into their specific role in production of gait. These findings will be useful for various types of surgery, biomechanics research, and rehabilitation programs.

Topographic anatomy of the ulnar tunnel.

PURPOSE: The aim of this study was to clarify the definition of the anterior wall of the ulnar tunnel and to reveal the topographical characteristics of the various components of the ulnar tunnel. MATERIALS AND METHODS: Twenty-two forearms from 11 embalmed cadavers (7 males, 4 females; mean age, 67.8 years) were carefully dissected. RESULTS: In all cases, the anterior wall of the ulnar tunnel comprised the hypothenar fascia, which originated from the tendon of the flexor carpi ulnaris muscle. The palmar carpal ligament, the distal extent of the antebrachial fascia, was located deep to the anterior wall and formed only the anterior boundary of the proximal hiatus of the ulnar tunnel. The hypothenar fascia was attached to the flexor retinaculum at 15.2 mm lateral to the pisiform bone. However, the palmar carpal ligament was attached to the flexor retinaculum just lateral to the ulnar artery; the distance between the attachment of the palmar carpal ligament and the pisiform bone was 8.7 mm. Anatomical variations potentially associated with ulnar nerve compression were observed. The accessory abductor digiti minimi muscle and the fibrous band crossing the ulnar nerve in the ulnar tunnel were found in 27 and 23 % of forearms, respectively. CONCLUSION: A more detailed description of the anterior wall of the ulnar tunnel than was previously available is presented herein, and topographic and metric data regarding each structure of the tunnel are reported.

The number and cycle of rat vibrissae according to topographic arrangement.

This study investigated the cycle of rat vibrissae by counting their number relative to their topographic arrangement. The average duration of maintaining single or double vibrissal shafts was analyzed. The ratio of the lifetime of the single and double shafts was around 3:2 weeks. The rostral and caudal vibrissae had relatively short and long cyclic durations, respectively; this difference may be related to their length and function.

The anatomical origin and course of the angular artery regarding its clinical implications.

BACKGROUND: The purposes of this study were to determine the morphological features and conceptualize the anatomical definition of the angular artery (AA) as an aid to practical operations in the clinical field. MATERIALS AND METHODS: Thirty-one hemifaces from 17 Korean cadavers and 26 hemifaces from 13 Thai cadavers were dissected. RESULTS: The topography of the AA was classified into 4 types according to its course: Type I (persistent pattern), in which the AA traverses the lateral side of the nose (11%); Type II (detouring pattern), in which the AA traverses the cheek and tear trough area (18%); Type III (alternative pattern), in which the AA traverses the medial canthal area through a branch of the ophthalmic artery (22.8%); and Type IV (latent pattern), in which the AA is absent (26.3%). CONCLUSION: The findings of this study will contribute toward improved outcomes for cosmetic surgery involving the injection of facial filler by enhancing the understanding of AA anatomy.