Lateral branches of the facial artery and its clinical implications.

The facial artery is the main artery supplying blood to the face and is known to have facial branches of the inferior labial, superior labial, lateral nasal and angular arteries. These known major branches of facial artery run medially, however, there are sometimes branches of the facial artery heading laterally. The purpose of the present study was to investigate the lateral branches of the facial artery in face. We dissected facial branches of the facial artery in 74 cadaveric hemifaces. We investigated the presence of the lateral branches of the facial artery. Following parameters were investigated: lateral branch presence, the location of its origin, and the lateral branch diameter. Among the lateral branches, we evaluated the prevalence and diameter of the premasseteric branch. Lateral branches were observed in 48 of the 74 hemifaces (64.9%). The total number was 81 in the 48 hemifaces. The most common origin was between the inferior border of the mandible and inferior labial artery origin (42 of 81, 51.9%). The mean diameter of all lateral branches of the facial artery was 0.7 mm. Among the lateral branches, the premasseteric branches were present in 38 of 74 specimen (51.4%) and the mean diameter was 0.8 mm. The lateral branches of the facial artery may be registered in Terminologia Anatomica based on their prevalence. Accurate knowledge of the anatomy of the lateral branches of the facial artery is helpful for clinicians to avoid complications during facial procedures or maxillofacial surgeries.

Morphometric analysis of the upper lip in Koreans.

The aims of this study were to provide the various dimensions of the philtrum and upper red lip in Korean young adults and to identify morphological characteristics of these structures in Koreans. A total of 10 dimensions of the philtrum and upper red lip were measured in 251 healthy young adults. Various indices were calculated among the measured features. The philtrum could be classified into three types according to its shape and index data. The mean height of the philtrum was 15.6 mm and the mean width of the mouth was 45.5 mm. The width of the superior and inferior philtrum, the height of philtrum, the width of the mouth, and the height of the upper red lip were significantly larger in males than in females (p < 0.05). A subtle morphological difference in Cupid bow was observed between the genders. There was a negative correlation between the length of the philtral column and the height of the upper red lip (p < 0.05). Furthermore, differences were identified in the dimensions of the philtrum and the upper red lip between Koreans and Caucasians. The results of this study could be a useful morphological basis for correction and reconstruction of the upper lip.

Centralization or decentralization of facial structures in Korean young adults.

It is well known that facial beauty is dictated by facial type, and harmony between the eyes, nose, and mouth. Furthermore, facial impression is judged according to the overall facial contour and the relationship between the facial structures. The aims of the present study were to determine the optimal criteria for the assessment of gathering or separation of the facial structures and to define standardized ratios for centralization or decentralization of the facial structures.Four different lengths were measured, and 2 indexes were calculated from standardized photographs of 551 volunteers. Centralization and decentralization were assessed using the width index (interpupillary distance / facial width) and height index (eyes-mouth distance / facial height). The mean ranges of the width index and height index were 42.0 to 45.0 and 36.0 to 39.0, respectively. The width index did not differ with sex, but males had more decentralized faces, and females had more centralized faces, vertically. The incidence rate of decentralized faces among the men was 30.3%, and that of centralized faces among the women was 25.2%.The mean ranges in width and height indexes have been determined in a Korean population. Faces with width and height index scores under and over the median ranges are determined to be "centralized" and "decentralized," respectively.

Microanatomy of the infraorbital canal and its connecting canals in the maxilla using 3-D reconstruction of microcomputed tomographic images.

The current study investigated the anatomy of the infraorbital canal (IOC) and its related small canals in the maxilla. Twenty-eight hemimaxillae from human cadavers were studied. The samples were scanned using microcomputed tomography, and then images were three-dimensionally reconstructed using computer software. The branch point of the canal into the anterior superior alveolar nerve from the IOC occurred at about one third along the length of the IOC in the anterior direction. Just over half of the cases had 1 canal. The branch arose either laterally (21/28) or inferiorly (7/28) from the IOC. There was a canal located at the inferior lateral border of the piriform aperture in all cases. The distribution of the canals in the maxilla is represented indirectly by the course and distribution of the nerve and blood vessels therein. This distribution could explain various phenomena encountered in the clinical field.

Anatomical verification and designation of the superficial layer of the temporalis muscle.

The temporalis muscle, which is one of the masticatory muscles, enables elevation and retraction of the mandible. Direct injury to the temporalis muscle, facial nerve, or temporal fat pad during cranial-base surgery can cause temporal hollowing. The temporalis muscle is currently described in almost all atlases and textbooks as comprising a single layer. In this study, a superficial layer of the temporalis muscle is described, clarifying the anatomy of this muscle. Twenty heads of adult cadavers were dissected. The gross anatomy of the temporalis muscle was examined after removing the skin, subcutaneous tissue, superficial temporal fascia, and deep temporal fascia. The superficial layer of the temporalis muscle was clearly distinguishable from the deep layer. The superficial layer originated from the same region as the deep layer, and the muscle fibers of the two layers were intermingled in the superior part of the muscle. The deep layer of the temporalis muscle, which is referred to in textbooks and atlases simply as the temporalis muscle, was exposed after removing the superficial layer. The existence of this superficial layer was confirmed herein both histologically and by magnetic resonance imaging. Henceforth, the superficial layer of the temporalis muscle must be included in descriptions of the temporalis muscle in anatomy textbooks and atlases. The findings of this study are important not only from the perspective of simply acquiring correct anatomical knowledge, but also from the surgical perspective in preventing temporal hollowing during related surgical procedures.

Are There Other Muscle Fibers on the Orbicularis Oris Muscle in the Upper Lip?

BACKGROUND: The elevator muscles of the upper lip are the levator labii superioris alaeque nasi, levator labii superioris, and zygomaticus minor muscles, which function by means of their insertions into the skin of the upper lip. However, many textbooks and journal articles state that no muscle fibers are present on the orbicularis oris muscle in the upper lip. The authors attempted to determine whether there is a superficial muscle layer in addition to the orbicularis oris muscle in the upper lip. METHODS: The authors performed gross dissections of 10 formalin-fixed cadavers and applied micro-computed tomography to six formalin-fixed cadavers. The fine dissection of the upper lip was performed in a layer-by-layer manner that elucidated its muscle layers. The entire layer of the upper lip was separated and pretreated with phosphotungstic acid for micro-computed tomography. The samples used for micro-computed tomography were repurposed for use in histologic analysis. An ultrasonography study was also performed. RESULTS: The presence of a muscle layer on the orbicularis oris muscle was confirmed in all samples. The elevator muscle fibers of the upper lip formed a layer by combining with connective tissue. Micro-computed tomography indicated lower terminal insertions of the elevator muscles throughout the upper lip. All parts of the upper lip skin were inserted into the orbicularis oris muscle. The histologic findings were similar to those of micro-computed tomography. CONCLUSION: The authors' findings could be used to improve aesthetic and surgical procedures performed on the upper lip, such as correction of gummy smile and transverse upper labial crease, or postresection reconstruction of the upper lip.

The morphology of the rat vibrissal follicle-sinus complex revealed by three-dimensional computer-aided reconstruction.

The vibrissal follicle-sinus complex (FSC) is a sensory receptor of the mammalian integumentary system that is located around the mouth. The purpose of the present study was to identify the actual 3-dimensional structure of the rat vibrissal FSC. Rat skin tissue was serially sectioned at a thickness of 10 µm and then stained with Masson's trichrome. The serial sections were reconstructed 3-dimensionally using Reconstruct software. The rat vibrissal follicle is a spindle-shaped structure that is embedded within a blood sinus and enveloped within a thick collagenous capsule. The vibrissal FSC is innervated by the deep vibrissal and superficial vibrissal nerves. The deep vibrissal nerve, travelling in the basal-to-apical direction, penetrates the thick collagenous capsule of the vibrissal FSC. The sinus system can be divided into a superior portion, known as the ring sinus, and an inferior portion, known as the cavernous sinus. The ring sinus contains a C-shaped structure, the ringwulst, which is suspended from the mesenchymal sheath of the follicle. Collagenous trabeculae can be seen in the cavernous sinus but not in the ring sinus. The ring sinus encircles the follicle obliquely and asymmetrically. The ringwulst encircles the follicle incompletely, in a C-shaped fashion. This study has demonstrated the previously underappreciated 3-dimensional structure of the vibrissal FSC, which differs from previously reported descriptions, and provides data that will enhance the understanding of vibrissal function.

Variations in the trabecular bone ratio of the maxilla according to sex, age, and region using micro-computed tomography in Koreans.

These cortical and trabecular bones maintain general bone structure. Bone mineral density (BMD) changes according to increasing age, sex, and teeth loss. From previous studies, the evaluation of BMD changes depended on conventional radiographic analysis. This study investigated the trabecular bone ratio (TBR) in maxillary bone samples based on data obtained by micro-computed tomography and estimated variations in BMD according to age, sex, and tooth loss. Thirty-eight specimens were scanned with micro-computed tomography and reconstructed three-dimensionally. Sections were made parallel to the axis of each tooth, and the TBR was measured. Data were statistically analyzed with 1-way analysis of variance and paired t-tests (α=0.05). The TBR differed significantly (P<0.05) in each tooth region in the dentate group but not in the edentulous group. The mean TBR was higher in men than in women. The TBR reduced more with increasing age in the dentate group than in the edentulous group. The TBR varies according to the presence of teeth, sex, and age in specific teeth regions.

Trabecular bone ratio of mandible using micro-computed tomography in Korean.

Cortical bone and trabecular portion play important roles in maintaining the general structure of bone. It has been reported that a decrease in bone mineral density is related with increasing age, sex, and teeth loss. However, most of the studies were done with conventional radiographic analysis. In addition, data from Korean population are rare. The aim of this study was to analyze trabecular pattern of the mandible using micro-computed tomography. Thirty-nine specimens of the mandible were prepared. Specimens were scanned with micro-computed tomography and reconstructed three-dimensionally. Sections were made parallel to the axis of each tooth. Trabecular bone ratio (TBR) was measured. Data were statistically analyzed with 1-way analysis of variance (alpha = 0.05). There was a statistically significant difference of TBR between dentate and edentulous mandibles in the molar region. Trabecular bone ratio of edentulous mandible in males was greater than that in females. Trabecular bone ratio of dentate mandibles reduced regularly with increasing age, whereas that of edentulous mandibles did not. It could be concluded that there were statistically significant differences in TBR according to presence of tooth, sex, and increasing age on specific areas.

Female-to-male proportions of the head and face in Koreans.

It is well known that the head and face are smaller in female subjects than in male subjects. However, almost all previous studies have quantified the size difference between female and male subjects as simple numerical values, which might not clarify the difference. The present study evaluated the female-to-male proportions of the head and face so as to clarify the sex-related differences. A total of 1939 female subjects and 1398 male subjects were divided into 3 age groups: young (20-39 y), middle-aged (40-59 y), and elderly (60-79 y). The dimensions were classified into 3 categories: 5 cephalic, 3 frontal facial, and 6 lateral facial. The female-to-male proportions of individual dimensions were compared in the 3 age groups using the following formula: female measurement value x 100/(mean of male measurement value). The female-to-male proportions of the cephalic dimension increased with age, with the female cephalic dimensions overall being about 96% of the male cephalic dimensions. The female-to-male proportions of the frontal facial dimension were constant across the age groups, with the female frontal facial dimensions overall being 95% of the male frontal facial dimensions. The female lateral facial dimension increased markedly from the young to middle-aged group and was constant or decreased slightly from the middle-aged to the elderly group. Overall, the female lateral facial dimensions were approximately 97% of the male lateral facial dimensions. The present study will suggest a new approach to elucidate those sex-related dimensional differences that are characteristic of female and male subjects.

Surface anatomy of the lip elevator muscles for the treatment of gummy smile using botulinum toxin.

OBJECTIVE: To propose a safe and reproducible injection point for botulinum toxin-A (BTX-A) as a supplementary method for the treatment of gummy smile, as determined by assessment of the morphologic characteristics of three lip elevator muscles. MATERIALS AND METHODS: A total of 50 hemi-faces from 25 adult cadavers (male 13, female 12; ages, 47 to 88 years) were used in this study. Topographic relations and the directions of the lip elevator muscles (ie, levator labii superioris [LLS], levator labii superioris alaeque nasi [LLSAN], and zygomaticus minor [ZMi]), were investigated. Possible injection points were examined through the study of predetermined surface landmarks. RESULTS: The insertion of the LLS was covered partially or entirely by the LLSAN and the ZMi, and the three muscles converged on the area lateral to the ala. The mean angle between the facial midline and each muscle vector was 25.8 +/- 4.8 degrees for the LLS, 55.7 +/- 6.4 degrees for the ZMi, and -20.2 +/- 3.2 degrees for the LLSAN; no significant differences were noted between male and female subjects or between left and right sides. The three vectors passed near a triangular region formed by three surface landmarks. The center of this triangle, named the "Yonsei point", was suggested as an appropriate injection point for BTX-A. The clinical effectiveness of the injection point was demonstrated in selected cases with or without orthodontic treatment. CONCLUSIONS: Under careful case selection, BTX-A may be an effective treatment alternative for patients with excessive gingival display caused by hyperactive lip elevator muscles.

External and Internal Diameters of the Facial Artery Relevant to Intravascular Filler Injection.

BACKGROUND: Vision loss and skin necrosis caused by an accidental intraarterial embolism or vascular compression are rare but devastating complications when injecting filler materials into the face. METHODS: The external and internal diameters and wall thicknesses of the facial artery and its branches were measured from 41 formalin-embalmed cadavers after removing connective tissues attached to the arterial wall. RESULTS: The diameter and thickness of the facial artery exhibited significant interregional differences. The external and internal diameters of the facial artery were 1.9 ± 0.4 and 1.2 ± 0.3 mm (mean ± SD), respectively, at the inferior border of the mandible; 1.7 ± 0.3 and 1.2 ± 0.3 mm in the vicinity of the inferior labial artery; 1.5 ± 0.3 and 1.0 ± 0.3 mm at the mouth corner; 1.4 ± 0.3 and 0.9 ± 0.2 mm in the vicinity of the superior labial artery; and 1.1 ± 0.2 and 0.7 ± 0.2 mm in the vicinity of the lateral nasal artery. The external and internal diameters at the proximal parts of the inferior labial artery, superior labial artery, and lateral nasal artery were 1.0 ± 0.3 and 0.6 ± 0.2 mm, 0.9 ± 0.3 and 0.6 ± 0.2 mm, and 0.8 ± 0.2 and 0.5 ± 0.2 mm, respectively. CONCLUSION: Morphometric examinations of the facial artery under stereomicroscope observation as performed in the present study are expected to be more accurate than direct measurements obtained during cadaveric dissection or conventional histologic evaluations.

Anatomical Consideration for the Safe Elevation of the Deep Circumflex Iliac Artery in Flap Surgery.

BACKGROUND: Deep circumflex iliac artery osteocutaneous flap transfer has frequently been applied to large defects in the maxillary and mandible regions, but the use rate has decreased gradually because of the complicated anatomy of the deep circumflex iliac artery. This study investigated the comprehensive anatomy of the deep circumflex iliac artery in relation to flap surgery with the aim of providing navigational guidelines for safe deep circumflex iliac artery harvesting. METHODS: Sixty-two sides of the hemi-abdominal wall were dissected in fixed Korean cadavers. Several dimensions of the deep circumflex iliac artery and its positional relationships with surgical landmarks were measured, and the patterns of the arterial supply and anastomosis were identified. RESULTS: The mean distance between the anterior superior iliac spine and the lateral border of the femoral artery was 57.5 mm. The deep circumflex iliac artery generally originated almost at the same level as the inguinal ligament, and its highest level was 14.8 mm superior to that ligament. Emerging points of the ascending branch were observed both medial and lateral to the anterior superior iliac spine, but no transverse branch pierced the transversus abdominis muscle medial to the anterior superior iliac spine. CONCLUSIONS: The incision line for safe deep circumflex iliac artery harvesting was parallel and 2 cm superior to the inguinal ligament and 6 cm from the anterior superior iliac spine. This position of the safe incision line can be easily determined using the thumb. Sex differences in the incidence of the deep circumflex iliac artery originating above or below the inguinal ligament will be another useful guide for easily detecting the deep circumflex iliac artery.

Macroscopic Innervation of the Dura Mater Covering the Middle Cranial Fossa in Humans Correlated to Neurovascular Headache.

The trigeminovascular system within the cranial dura mater is a possible cause of headaches. The aim of this study is to investigate macroscopically dural innervation around the middle meningeal artery (MMA) in the middle cranial fossa. Forty-four sides of the cranial dura overlying the skull base obtained from 24 human cadavers were stained using Sihler's method. Overall, the nervus spinosus (NS) from either the maxillary or mandibular trigeminal divisions ran along the lateral wall of the middle meningeal vein rather than that of the MMA. Distinct bundles of the NS running along the course of the frontal branches of the MMA were present in 81.8% of cases (N = 36). Others did not form dominant nerve bundles, instead giving off free nerve endings along the course of the MMA or dural connective tissue. The distribution of these nerve endings was similar to that of the course of the frontal, parietal and petrosal branches of the MMA (11.4%). The others were not restricted to a perivascular plexus, crossing the dural connective tissues far from the MMA (6.8%). These findings indicate that the NS generally travels alongside the course of the frontal branches of the MMA and terminates in the vicinity of the pterion.

Sex determination using nonmetric characteristics of the mandible in Koreans.

The mandible is the largest and hardest facial bone and retains its shape better than other bones in the forensic and physical anthropologic field. The mandible can be used to distinguish among ethnic groups and between sexes. We examined the morphological characteristics of the mandibles of 102 Koreans of either sex. Of 13 nonmetric items of the mandible, the characteristic that best allowed the sexes to be distinguished was the contour of the lower border of the mandible: rocker-shaped mandibles predominated in males (68.1%), whereas most females (84.6%) exhibited a straight mandible. In addition, the mental region was shaped differently between the sexes: the shape of the chin in most males was generally bilobate or square (91.7%), whereas the chin in females was either square (45.5%) or pointed (54.5%). In this study, the positive predict values of male and female were 92.5% and 73.7%, respectively. Therefore, the nonmetric method used to analyze the mandible in this study can be used for sex discrimination.

Topography and spatial fascicular arrangement of the human inferior alveolar nerve.

BACKGROUND: Topography and fascicular arrangement of the inferior alveolar nerve (IAN) can provide critical information for the estimation of damage to IAN based on patient symptoms, or conversely to evaluate the symptoms resulting from injury to the IAN. PURPOSE: The fascicular composition and organization of the IAN were determined to confirm the microarchitecture of the IAN bundles into each of the mandibular teeth, including the composition of the mental nerve. MATERIALS AND METHODS: The IAN within the mandibular canal (MC) was examined in 30 hemifaces of embalmed Korean cadavers. RESULTS: The most common patterns of nerve fascicle innervation to the mandibular teeth could be grossly classified into three: (1) the superior buccal portion of the IAN innervating the molars, (2) the superior portion innervating the premolars, and (3) the superior lingual or the superior lingual and inferior lingual portions in the posterior MC and the lingual portions in the anterior MC, innervating the incisors and canine. The buccal two-thirds portion of the IAN was composed of the mental nerve. CONCLUSION: The IAN had distinctive fascicular organizations, which make it possible to forecast the degree, location, and extent of nerve damage according to presenting symptoms.

The trend of body donation for education based on Korean social and religious culture.

Until a century ago, Korean medicine was based mainly on Oriental philosophies and ideas. From a religious perspective, Chinese Confucianism was prevalent in Korea at that time. Since Confucianists believe that it is against one's filial duty to harm his or her body, given to them by their parents, most Koreans did not donate their bodies or organs for education in the past. However, by the end of the 20th century, a unique fusion of Western and Oriental medicines were produced on the Korean Peninsula, revolutionizing traditional perspectives on the human body, mortality, and the relationship of medical science to society. Koreans began to think about others' lives as well as their own by realizing the importance of donating one's organs and bodies for scientific purposes. Since then, the number of people donating their bodies to Korean medical and dental schools for the purpose of improving academic learning has increased dramatically. In response, Korean medical schools have begun to hold various types of funeral ceremonies to honor body donors. We have compared such ceremonies performed in Korea with those performed in the United States of America and Taiwan. These ceremonies are viewed as a suitable way to pay proper respect to the dead and to promote knowledge about body donation programs in Korea. Overall, the transition of religions and social ethics in Korea has greatly facilitated body bequeathal programs, benefiting both medical education and the Korean public health administration.

Topography of the masseter muscle in relation to treatment with botulinum toxin type A.

OBJECTIVE: The objective of this study was to provide the safest and most efficient site for injection of botulinum toxin type A into the masseter muscle. STUDY DESIGN: This study was performed on 40 hemifaces from cadavers. The surface of the masseter was compartmentalized into areas I to VIII. Areas I, III, V, and VII were assigned to represent the upper 4 compartments from the posterior aspect of each muscle, and areas II, IV, VI, and VIII were assigned to represent the lower 4 compartments. RESULTS: The parotid gland usually covered compartments I and II, and the marginal mandibular branch of the facial nerve was located a mean of 7.4 mm above the inferior mandibular margin. The parotid duct was usually located above the reference line connecting the tragus and the cheilion. CONCLUSION: The center of compartment VI is the safest and most efficient injection site for botulinum toxin type A into the masseter muscle.

Microanatomy of the incisive canal using three-dimensional reconstruction of microCT images: an ex vivo study.

OBJECTIVES: The purpose of this study was to investigate the general structure of the incisive canal (IC) using 3-dimensional reconstruction and to classify into various types according to several criteria. STUDY DESIGN: The materials used in the study were 56 anterior maxillae harvested from human cadavers. The specimens were scanned with microscopic computerized tomography (microCT), and the resulting microCT images were reconstructed in 3 dimensions. RESULTS: Many ICs had 1 foramen inferiorly and 2 foramina superiorly, and the separating level was just beneath the nasal floor. The middle part of the IC was not always a single hollow canal. Single-channel, 2-channel, 3-channel, and even 4-channel ICs were observed. The ICs were classified into 4 types according to the lateral shape of the canal: vertical-straight, vertical-curved, slanted-straight, and slanted-curved. CONCLUSIONS: This study disclosed the detailed morphologic features of the IC, which will be helpful in the placement of local anesthesia or implants.

Horizontal angular asymmetry of the face in korean young adults with reference to the eye and mouth.

PURPOSE: Organs and structures develop symmetrically, but various degrees of asymmetry can also develop because of the effects of function and disease. The human face is often asymmetrical, but faces can be perceived as beautiful even if they are asymmetrical. The purpose of the present study was to investigate horizontal angular asymmetry of the face. MATERIALS AND METHODS: The angle between the horizontal line through the bilateral exocanthions and the line though the bilateral mouth corners of the face was measured on standardized frontal facial photographs of 1,282 volunteers (18 to 29 years of age; 761 males, 521 females). RESULTS: The magnitude of the angle was 0.2 +/- 1.4 and 0.3 +/- 1.3 degrees (mean +/- SD) in males and females, respectively. Faces were classified into 3 types relative to the parallel type. The incidence of the parallel type, the right-dominant type (>/=1 degree), and the left-dominant type (