Visualization of the infratemporal fossa: enhancing anatomical learning through three-dimensional modeling.

The infratemporal fossa and pterygopalatine fossa are critical pathways for blood vessels and nerves leading to the orbit, nasal cavity, and oral cavity. Anatomical observation of these areas is challenging for learners due to their complex connections with surrounding structures and their deep location within the body. Since it is not easy to understand this area in three dimensions with only textbook images, there is a need to produce three-dimensional (3D) content. Most existing 3D data have reconstructed the digital imaging and communication in medicine files from computed tomography images with high accuracy; however, the surrounding structures often obstruct the view. For this reason, this project utilized Cinema4D (R18; Maxon) software to refine the modeled bones and to create 3D models of muscles, blood vessels, and nerves that accurately represent their anatomical shapes and pathways. To facilitate easier access for learners via PC, the content was converted into PDF format. This enables the educational materials to be more easily viewed and the main structures more clearly observed using a computer-based viewer.

Anatomical classification of middle rectal arteries regarding detailed vasculature patterns.

This study aimed to clarify the anatomy of middle rectal artery and pelvic vasculature patterns, and to provide schematic information in a manner applicable to the total mesorectal excision. Forty sides of pelvis from 20 formalin-embalmed cadavers (10 male, 10 female) were dissected, and all the pelvic vasculatures from the internal iliac artery were investigated, focusing on the middle rectal artery. Middle rectal arteries were classified into major types depending on their vascular origins. Each type was subdivided into minor types according to variability of the pelvic vasculature. A middle rectal artery was identified in 18 out of 20 cadavers, and in 25 out of 40 pelvic sides. In most cases, the middle rectal artery originated from the internal pudendal artery or inferior gluteal artery. These two arteries arose directly from the anterior trunk of the internal iliac artery or were bifurcated from the gluteal-pudendal trunk. In rare cases, these arteries arose from the posterior trunk of the internal iliac artery. The other origins of the middle rectal artery included the gluteal pudendal trunk, inferior vesical artery, internal iliac artery, obturator artery, and the prostatic artery, and the pelvic vasculatures in these cases also presented variability. The detailed anatomical findings related to the middle rectal artery and pelvic vasculatures are noteworthy for their improved clinical applicability.

Association of Physical Activity and Lower Respiratory Tract Infection Outcomes in Patients With Cardiovascular Disease.

Background To investigate the dose-response association between physical activity and lower respiratory tract infection (LoRI) outcomes in patients with cardiovascular disease. Methods and Results Using the Korean National Health Insurance data, we identified individuals aged 18 to 99 years (mean age, 62.6±11.3 years; women, 49.6%) with cardiovascular disease who participated in health screening from January 1, 2009, to December 31, 2012 (n=1 048 502), and were followed up until 2018 for mortality and until 2019 for hospitalization. Amount of physical activity was assessed using self-reported questionnaires and categorized into 5 groups: 0 (completely sedentary), <500, 500 to 999, 1000 to 1499, and ≥1500 metabolic equivalents of task min/wk. After controlling for various confounders, adjusted hazard ratios (95% CIs) were 1.00 (reference), 0.74 (0.70-0.78), 0.66 (0.62-0.70), 0.52 (0.47-0.57), and 0.54 (0.49-0.60) for LoRI mortality, and 1.00 (reference), 0.84 (0.83-0.85), 0.77 (0.76-0.79), 0.72 (0.70-0.73), and 0.71 (0.69-0.73) for LoRI hospitalization among those engaging in physical activity of 0, <500, 500 to 999, 1000 to 1499, and ≥1500 metabolic equivalents of task min/wk, respectively. Assuming linear association between 0 and 2000 metabolic equivalents of task min/wk, each 500-metabolic equivalents of task min/wk increase of physical activity was associated with reduced LoRI mortality and hospitalization by 22% and 13%, respectively. The negative association was stronger in the older population than in the younger population (P for interaction <0.01). Conclusions In patients with cardiovascular disease, engaging in even a low level of physical activity was associated with a decreased risk of mortality and hospitalization from LoRI than being completely sedentary, and incremental risk reduction was observed with increased physical activity.

A New Anatomical Classification for Tibialis Posterior Tendon Insertion and Its Clinical Implications: A Cadaveric Study.

The variations in the tibialis posterior tendon (TPT) could not be defined by previous classification; thus, this study used a larger-scale cadaver with the aim to classify the types of TPT insertion based on the combination of the number and location of TPT insertions. A total of 118 feet from adult formalin-fixed cadavers were dissected (68 males, 50 females). The morphological characteristics and measurements of TPT insertion were evaluated. Four types of TPT insertions were classified, wherein the most common type was type 4 (quadruple insertions, 78 feet, 66.1%), which was divided into four new subtypes that were not defined in the previous classification. The second most common type was type 3 (triple insertions, 25 feet, 21.2%) with three subtypes, including the new subtype. Type 2 was found in 13 feet (11%), and the rarest type was type 1 (2 feet, 1.7%), wherein the main tendon was only attached to the navicular bone and the medial cuneiform bone. We suggest high morphological variability of the TPT in relation to the insertion location, along with the possibility of significant differences according to race and gender. Moreover, this classification will help clinicians understand adult flatfoot deformity-related posterior tibial tendon dysfunction (PTTD).

3D morphological classification of the nasolacrimal duct: Anatomical study for planning treatment of tear drainage obstruction.

BACKGROUND: The purpose of this study is to analyze and classify morphological features of the nasolacrimal duct (NLD) through 3D reconstruction to help understand the causes and treatment of NLD obstruction. METHODS: In this study, we included 63 males and 55 females who underwent autopsy without NLD obstruction with ages ranging from 20 to 78 years. The NLD was defined from the lacrimal fossa to the opening of the BNLD to the inferior meatus, and all continuous CT images showing the NLD were selected. Segmentation was performed semi-automatically, and the reconstruction and measurement of NLD was performed using the Mimics program. RESULTS: Overall NLD length, bony nasolacrimal duct (BNLD) length, anteroposterior and transverse diameters at the entrance to the BNLD, anteroposterior and transverse smallest diameters of the BNLD, BNLD volume, and lacrimal sac BNLD angle were significantly higher in males than females (p < .05). BNLD direction in the coronal plane was slightly more likely to be inward. The most common type in both sexes was cylinder type (42.0%), males were more likely to have lower-thicker types (34.1%), and females more likely to have upper-thicker types (22.7%). CONCLUSION: There were sex differences in NLD measurements, and females had significantly smaller NLDs. These results may partially explain the increased prevalence of primary acquired NLD obstruction in females. The BNLD tends toward the midline, and inclines posteriorly.

A novel anatomical consideration on the exposed segment of the facial artery.

An understanding of the location and depth of the facial artery (FA) is essential in aesthetic surgery and various cosmetic procedures. The purpose of this study was to clarify the three-dimensional (3D) topography of the exposed segment (ES) of the FA and to provide information to help minimize complications during clinical procedures. From 50 embalmed adult cadavers, the undissected and dissected hemifaces were scanned and reconstructed using the 3D scanner. Then the topographic location of the ES was identified and measured from the superimposed the 3D images. The ES was observed in 82% of the whole specimens. The exposure patterns of the ES were examined, and classified into three types: Type I, one site exposed pattern (74%); Type II, two sites exposed pattern (8%); and Type III, nonexposed pattern (18%). The extent of the ES was located at 2.2 mm above and 4.2 mm below the cheilion (Ch)-otobasion inferius line, and 20.0 to 25.2 mm from the Ch on the lateral aspect. In the frontal view, the average distance from the mid-pupillary line to the ES was 7.1 mm, and from the lateral canthal line to the ES was 6.1 mm. The ES was 7.6 mm below the skin surface. The results of this study will help to provide safe guidelines for filler injections as well as selecting the safe regions in various clinical procedures. Clin. Anat. 33:257-264, 2020. © 2019 Wiley Periodicals, Inc.

Positional relationship of superior and inferior labial artery by ultrasonography image analysis for safe lip augmentation procedures.

The aim of this study was to use ultrasonography to determine the locations and distributions of the superior labial artery (SLA) and the inferior labial artery (ILA) relative to the vermilion border (VB). Sixty healthy Korean volunteers (35 males, 25 females; age, 21-36 years) were investigated using ultrasonography. The participants had not received any noninvasive treatment or surgical procedure in the facial regions during the previous 6 months. Based on the VB, the overall thicknesses of the upper and lower lips were 9.4 ± 0.4 mm (mean ± SD) and 10.9 ± 0.7 mm, respectively. In most cases, the labial arteries were located in the wet mucosal layer on both the upper (35-57%) and lower lips (28-55%), respectively. In the upper lip, the SLA was in the intramuscular layer in 20-45% of cases, making it the second most common type. At some of the measuring points, the SLA was observed more often in the intramuscular layer than in the wet mucosal layer. In the lower lip, the ILA was also located in the dry mucosa (5-27%). The dry-wet mucosal junction is unclear in the lip area, and the ILA was commonly observed at the dry-wet mucosal junction. The arterial depth was 5.3 ± 0.3 mm in the upper lip and 4.2 ± 0.4 mm in the lower lip. The SLA and ILA are evenly distributed over all parts of the oral mucosa. Injection procedures for lip augmentation should therefore use very superficial approaches. Clin. Anat. 33:158-164, 2020. © 2019 Wiley Periodicals, Inc.

A Detailed Analysis of the Blood Supply to the Subscapularis Muscle.

This study aimed to provide a comprehensive description of the arterial supply to the subscapularis (SSC) muscle. This will provide critical information for various surgical procedures. Ten specimens of embalmed Korean cadavers were dissected and subjected to modified Sihler's method to reveal the branching pattern of the arteries surrounding the subscapularis, and its intramuscular blood supply. The SSC muscle was generally supplied by branches from the subclavian artery (suprascapular artery, supraSA; circumflex scapular artery, CxSA; and dorsal scapular artery, dSA) and the axillary artery (subscapular artery, subSA; lateral thoracic artery, LTA; posterior circumflex humeral artery, PCxHA; and a branch of the axillary artery, AAbr). The anterior aspect of the muscle was supplied by the subSA, LTA, CxSA, supraSA, and AAbr. The posterior aspect of the muscle was supplied by the supraSA, PCxHA, and subSA. The dSA was more scarcely distributed than the other arteries. In two cases, the dSA supplied the portion of the muscle near the medial border of the scapular. The anterior side of the muscle tendon was supplied by the CxSA, and its posterior side was supplied by the PCxHA. The subSA can be considered to be the main branch supplying the SSA based on its distribution area of arteries. It was mostly situated within the lower region of the SSC. After distributing to the anterior surface of the SSC, some branches of the subSA reached the posterior surface as perforating branches. Clin. Anat. 32:642-647, 2019. © 2019 Wiley Periodicals, Inc.

New Insight Regarding the Zygomaticus Minor as Related to Cosmetic Facial Injections.

The present study aimed to determine the arrangement and terminal attachments of the zygomaticus minor (Zmi) muscle fibers connecting the orbital and mouth regions. The Zmi was examined in 32 specimens of embalmed Korean adult cadavers. The Zmi was present in all 32 specimens (100%). In 31 of the specimens (96.9%), the Zmi that inserted into the upper lip was formed by muscle fibers that arose from the zygomatic bone and muscle fibers that extended from the orbicularis oculi (OOc) muscle. In 14 of the specimens (43.8%), some fibers of the Zmi that arose from the zygomatic bone blended with the inferior margin of the OOc, while the other fibers inserted into the upper lip. After the Zmi fibers blended with the inferior margin of the OOc, these fibers constituted the inferior and medial margins of the OOc. These fibers were then attached to the medial palpebral ligament, the maxilla, the levator labii superioris alaeque nasi muscle, and the depressor supercilii muscle. In 30 of 32 specimens (93.8%), muscle fibers that extended from the OOc constituted the lateral margin of the Zmi, usually descending to the level between the nasal ala and the vermilion border of the upper lip and inserting into the upper lip. The obtained data will be helpful for understanding their connected movements and in kinematics and electromyographic analyses, therapies involving injections of botulinum toxin Type A, and various types of facial surgery. Clin. Anat. 31:974-980, 2018. © 2018 Wiley Periodicals, Inc.

Topography of the dorsal nasal artery and its clinical implications for augmentation of the dorsum of the nose.

BACKGROUND: Injections of filler into the nose for dorsum augmentation have a higher risk of complications due to the complicated blood supply and anastomotic channels in this area. OBJECTIVES: The aim of this study was to determine the anatomical features and location of the dorsal nasal artery (DNA), and to provide clinical anatomical information to reduce side effects and severe complications in the perinasal area. METHODS: Using the 31 cadaveric noses in Asians, dissections and histologic examinations were performed to identify the location and depth of the vascular structures including DNA. RESULTS: Dorsal nasal artery ran downward at 20.3 ± 3.5 mm from the intercanthal line and the communicating branch that connected the bilateral DNAs was located 8.5 ± 3.5 mm inferior to the intercanthal line. The DNA was located at 4.4 ± 3.2 mm, 4.6 ± 4.4 mm, and 5.2 ± 4.4 mm lateral to the midline of the nose on the intercanthal, quadrisected, and bisected lines, respectively. At the level of nasal bone, DNA was located superficial to the muscular layer and it runs inferolaterally on dorsum on nose. It was running more deeply and located beneath the fibromuscular layer at the cartilaginous portion of the dorsum of nose. CONCLUSIONS: Injection into deep fatty layer may reduce the risk of arterial injury and the consequent complications. However, in a hooked nose, the tip of the needle traveling along the deep layer approaches the superficial layer due to the convexity of the hump as it passes over it, which can increase the probability of damaging the DNA.

Bilayered Structure of the Superficial Facial Fascia.

Background: The superficial facial fascia comprises the superficial musculoaponeurotic system (SMAS) and the temporoparietal fascia (TPF) and is regarded as a continuous monolayer. However, some evidence indicates that the superficial facial fascia consists of 2 layers in specific areas. Objectives: The authors evaluated the superficial facial fascia for bilayered regions. Methods: Twenty fresh cadavers (40 hemifaces) were dissected to observe the superficial facial fascia. Twelve cadavers were dissected to assess tensile strengths of the superficial and deep layers of the SMAS. Specimens were obtained from 2 cadavers for histologic analysis. Results: The SMAS and TPF were separable into superficial and deep layers, with intervening areolar tissue. The deep TPF was continuous with the deep SMAS inferiorly and the subgalea anteriorly. The superficial orbicularis oculi was invested by the superficial SMAS, whereas the deep orbicularis and the platysma were invested by the deep SMAS. Thus, 2 key structures addressed in facial rejuvenation are positioned in different surgical planes. Conclusions: Study results support the belief that the superficial facial fascia comprises 2 layers, with the superficial orbicularis oculi and platysma invested by different layers. These findings have implications for facial rejuvenation techniques that involve management of the SMAS and TPF.

Clinical Implications of the Extension of Platysmal Fibers on the Middle and Lower Face.

BACKGROUND: Despite the area of insertion of the facial portion of the platysma being broad and highly variable, the details of its pattern of extension and morphology are not well described in the medical literature. The aim of this study was to clarify the extension patterns of the platysma on the middle and lower face by topographic examination and detailed dissection. METHODS: A detailed dissection was performed in the cheek region of 34 cadaveric specimens. The anatomical aspects of the extent of the platysma were classified according to its area of coverage on the cheek. RESULTS: The location of the posterior fibers of the platysma passing behind the mandibular angle were located 17.1 ± 8.8 mm (mean ± SD) from the mandibular angle. The platysma was classified into patterns (A, B-1, B-2, and C) according to its coverage area: in type A (8.8 percent), areas S1 to S2, M1 to M3, and I1 to I3 were partially covered by the platysma; in type B-1 (58.8 percent), areas M1 to M3 and I1 to I3 were partially covered; in type B-2 (26.5 percent), areas M1 to M2 and I1 to I3 were partially covered; and in type C (5.9 percent), areas I1 to I3 were partially covered. CONCLUSION: The description of the extent of the facial portion of the platysma presented in this article provides detailed anatomical knowledge regarding the midface, and represents fundamentally important knowledge for surgeons conducting rhytidectomy and other facial operations.

Anatomical study of medial zygomaticotemporal vein and its clinical implication regarding the injectable treatments.

BACKGROUND: The medial zygomaticotemporal vein (MZTV), clinically known as sentinel vein, has been observed in the vicinity of the temporal branch of the facial nerve during endoscopic procedures aiming to lift the upper face. The aim of the present study was to describe the topography of the MZTV with reference to the superficial landmarks for providing detailed anatomical information during injectable treatment procedures. METHODS: Eighteen hemifaces were harvested from nine embalmed Korean adult cadavers (5 males and 4 females, mean age 76 years). The piercing location, vascular diameter, drainage pattern of the MZTV, and its relationship with the orbicularis oculi muscle (OOc) were recorded photographically, and using diagrams and written notes. RESULTS: The piercing point of the MZTV was located 26.8 ± 5.9 mm from the lateral epicanthus, 18.8 ± 6.9 mm lateral to the plane (HP) through the tragus and the lateral epicanthus, and 19.0 ± 5.4 mm superior to the plane (VP) through the lateral epicanthus point and perpendicular to the HP. The diameter of the MZTV at the piercing point was 1.9 ± 0.8 mm. All of the MZTV ultimately connected with the middle temporal vein (MTV). In particular, the MZTV was connected the MTV by anastomosing with the periorbital vein. Anastomosis of the MZTV and a well-developed periorbital vein was found in 27.8 % of cases. CONCLUSION: The physician must determine the location of the MZTV and should be able to accurately estimate its connection with significant veins at the temple to reduce the risk of severe complications during injectable treatments.

Anatomical considerations of the longitudinal pharyngeal muscles in relation to their function on the internal surface of pharynx.

The aim of this study was to clarify the topography of the longitudinal pharyngeal muscles and to relate the findings to pharyngeal muscular function. Forty-four specimens (22 right and 22 left sides) from embalmed Korean adult cadavers (13 males, 9 females; age range, 46-89 years; mean age, 69.2 years) were used in this study. The palatopharyngeus muscle originated from the palatine aponeurosis and the median part of the soft palate on oral aspect; it ran downward and lateralward, respectively. The palatopharyngeus muscle, which held the levator veli palatini, was divided into two bundles, medial and lateral, according to the positional relationship with the levator veli palatini. The lateral bundle of the palatopharyngeus muscle was divided into two parts: longitudinal and transverse. The pharyngeal longitudinal muscles were classified into the following four types (I-IV) depending on the area of insertion: they were inserted into the palatine tonsil, epiglottis, arytenoid cartilage, piriform recess, thyroid cartilage, and pharyngeal wall. The transverse part of the palatopharyngeus muscle plays a role as a sphincter. Palatopharyngeus and levator veli palatini muscles help each other to function effectively in the soft palate. The present findings suggest that the pharyngeal muscles are involved not only in swallowing but also in respiration and phonation via their attachment to the laryngeal cartilage.

Clinical anatomic considerations of the zygomaticus minor muscle based on the morphology and insertion pattern.

BACKGROUND: The zygomaticus minor muscle (Zmi) is involved in the expression of many different facial emotions. However, the details of its insertion pattern and morphology are not well described. OBJECTIVE: The aim of this study was to clarify the morphology and insertion pattern of the Zmi, and to provide clinical anatomic information that will help elucidate its roles in animation. MATERIALS AND METHODS: Fifty-four embalmed adult hemifaces (18 men and 12 women; mean age, 67.4 years) from 30 cadavers were used in this study. The dissection was performed with the aid of a surgical microscope. RESULTS: This muscle could be classified into 3 types (A-C). Type A, in which the Zmi attached only to the upper lip, was observed in 63.0% of cases (34/54) and could be subdivided into 2 types: straight (A-1; 31.5%, 17 cases) and curved (A-2; 31.5%, 17 cases). Type B, in which the Zmi was attached to both the upper lip and the lateral alar region, occurred in 27.8% of cases (15/54). In Type C (9.2% of cases, 5/54), there was either no or only undeveloped Zmi fibers. CONCLUSION: The present finding of Zmi fibers being attached to the alar region in many cases (27.8%) suggests that this muscle is involved in elevation of both the nose ala and upper lip during various facial animations.

Surgical consideration of the anatomic origin of the risorius in relation to facial planes.

BACKGROUND: Confusion exists as to the plane of the risorius with respect to the superficial musculoaponeurotic system (SMAS), the parotid fascia, and the masseteric fascia, which generally are considered origins of the risorius. OBJECTIVES: The authors attempted to clarify the origin of the risorius by topographic examination and dissection, which would provide valuable anatomic information for flap dissection in facelift surgery. METHODS: Detailed dissection was performed in the perioral region of 46 cadaveric specimens to discern the origin of the risorius in relation to the fascial layer. The anatomic aspects of the muscular arrangement and origin of the risorius were classified according to the location of attachment. RESULTS: The risorius originated solely from the fascial layer superficial to the SMAS in 27 specimens (58.7%; type A). It originated solely from the masseter tendon in 3 specimens (6.5%; type B) and from the fascial layers, both superficial and deep to the SMAS, in 16 specimens (34.8%; type C). CONCLUSIONS: The patterns of risorius origination identified in this study represent important anatomic reference information for flap dissection in facelift surgery.

Clinical implications of the middle temporal vein with regard to temporal fossa augmentation.

BACKGROUND: The middle temporal vein (MTV) traverses the temporal fossa between the superficial and deep layers of the deep temporal fascia. During filler injection into a deficient temporal fossa, filling agents may be inadvertently injected into the MTV, which results in vascular complications. OBJECTIVE: To investigate the course of the MTV to enable safe filler injection in the temple area. MATERIALS AND MATERIALS: The course and diameter of the MTV were measured in 18 hemifaces from 9 Korean cadavers. RESULTS: The MTV was located 23.5 and 18.5 mm above the zygomatic arch at the jugale and the zygion, respectively. The diameter of the MTV at its thickest point was 5.1 mm. A splitting and reuniting pattern, such that the MTV occupied more space than a single trunk, was observed in 28% of cases. CONCLUSION: We propose that the safest area for filler injection in temporal fossa augmentation is one finger width above the zygomatic arch.

Neuroanastomosis and the innervation territory of the mental nerve.

The aim of this study was to clarify the distribution pattern and innervation territory of the mental nerve (MN) in the skin and mucosa by topographic examination by Sihler's staining, thereby providing reference anatomical information for surgical procedures and to enable prediction of regions of sensory disturbance following nerve damage. Ten human specimens were subjected to Sihler's staining, which is a highly accurate method for visualizing the distribution of nerve fibers without altering their topography. Each branch of the MN overlapped adjacent branches (five cases), or else they were distributed individually at the lower lip (five cases). The MN anastomosed with some branches of the facial nerve near the mental foramen. Moreover, some branches of the MN anastomosed with the buccal nerve of the trigeminal nerve, which supplies sensation to the skin and mucosa over the lateral region of the lower lip (six cases). The details of the distribution pattern and innervations territory of the MN presented herein may enable the prediction of a region of sensory disturbance following MN damage. Moreover, knowledge of the pattern of synapses with adjacent branches of other nerves, such as the facial (marginal mandibular and cervical branches) and the buccal nerves, might help to improve our understanding around incomplete anesthesia during the surgical procedures in oral & maxillofacial region.

Morphology of the zygomaticus minor and its relationship with the orbicularis oculi muscle.

The aim of this study was to examine in detail the anatomic variations in the orbicularis oculi muscle (OOc) and relationship of the zygomaticus minor muscle (ZMi) with the OOc, thereby providing an anatomic basis for explaining facial animation and attachment to the periorbital muscle. Sixty-one hemifaces from embalmed Korean adult cadavers (34 males, 27 females; age range, 45-85 years; mean age, 62.6 years) were used in this study. The prevalence of cases in which the ZMi did not run straight from the upper lip, rather running straight to the corner of the levator labii superioris, was 36.1% (22/61), because the origin of ZMi covered the inferior border of the OOc. The prevalence of mixing of the belly of the orbital part of the outer edge of the OOc with the ZMi was 88.5%, and that of blending of the ZMi band into the lower inner corner of the OOc was 55.7%. The area of blending of the OOc and ZMi was located 17.8 mm down from the Frankfort plane and 8.9 mm lateral to the vertical line between the lateral canthus and the Frankfort plane in the lateral part of the OOc. At this position, the mixed belly extends medially for a distance of 16 mm. This research has identified the exact location where the ZMi and OOc blend and determined the relationship between the ZMi and the suborbicularis oculi fat. This result will be given as basic data for understanding facial expressions and for performing composite rhytidectomy.