Topographic Anatomy of the Zygomatico-Orbital Artery.

ABSTRACT: The zygomatico-orbital artery (ZOA) originating from the superficial temporal artery and supplying the lower temporal region superficially has been reported. Previous studies of this artery have used definitions that are too ambiguous for the results to be directly adapted to clinical practice, including since they have resulted in marked variations in the reported incidence ofthe artery. This study dissected 193 hemifaces of 123 fixed human cadavers aged 36 to 102 years (119 males and 74 females). The authors investigated the ZOA based on the following definition: (1) it originates from the superficial temporal artery, (2) it runs mostly above the zygomatic arch, and (3) it terminates below the superior border of the orbicularis oculi muscle. The incidence of the ZOA was 22.8% (44 cases of 193 sides), and its mean diameter was 1.1 mm. The meanvertical distances from the superior borderofthe zygomatic arch to the artery were 29.6, 17.8, and 2.9 mm at the jugale, zygion, and the origin of the ZOA, respectively. An accurate definition of the ZOA and accurate knowledge of its incidence and course could be important for clinicians to avoid unintentional complications in clinical practice.

Anthropometric Analysis of the Growth Proportions of the Head and Face in Koreans.

ABSTRACT: The present study is to identify primarily the morphological characteristics in the growth proportion of the head and face for young Korean (8-24 years) and compare the magnitude of growth changes to the sex-related differences. Total 1255 were divided into 3 age groups: childhood (8-10 years), adolescence (14-16 years), and young adult (20-24 years). The anthropometric assessments were performed with 11 landmarks on the head and facial dimensions. The standardized frontal and lateral head and face photographs were analyzed the craniofacial growth proportions and morphological features for the comparison of both sexes. The noteworthy differences of anthropometric measurements between sexes with growing were noted on the lower head height (22.6%, 17.8%), midface height (22.0%, 19.6%), lower face height (23.5%, 14.7%), and face length (21.1%, 14.9%), face breadth (14.8%, 11.3%) of males and females, respectively. Whereas the upper head height (7.9%, 6.0%) and upper face height (4.2%, 0%, respectively) were less growing features. The most remarkable changes are the dimension of midface height and lower face height in both sexes. The present study could demonstrate a fundamental example to elucidate the sex-related dimensional differences for the analysis of the growth proportion of both sexes in Koreans.

Topography of the orbital part of the lacrimal gland for treating epiphora using botulinum toxin injection.

The purpose of this study is to identify the location of the orbital part of the lacrimal gland using external landmarks to facilitate effective botulinum toxin A (BTX-A) injections for epiphora treatment. Dissections were performed on 45 hemifaces from 27 cadavers. The length, anterior protrusion, and thickness of the orbital part of the lacrimal gland were measured directly. The midpoint of the line running horizontal through the medial and lateral canthus was used as the horizontal reference point. Vertical lines perpendicular to the midpoint of the horizontal reference line were the vertical reference lines. The angles from the horizontal reference line to the lacrimal gland center and to the frontal tubercle were also measured. The length and thickness of the lacrimal gland were 12.8 and 2.4 mm, respectively. The lacrimal gland had an anterior protrusion of 4.1 mm from the superolateral orbital margin. The superior and inferior margins of the lacrimal gland were located 35.7° and 15.8° from the two reference lines, respectively. The angle from the horizontal reference line to the lacrimal gland center was 35.1°, which was similar to that to the frontal tubercle (34.4°). The orbital part of the lacrimal gland was more inferior in elderly subjects and the angle between the horizontal reference line and its center was 35.1°, which was similar to the location of the frontal tubercle. The location of this tubercle can help clinicians to perform BTX-A injections into the lacrimal gland, thereby enhancing the effectiveness of epiphora treatment.

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.

Macro/microscopic distribution of the dorsal nerve of penis in human glans penis.

This study aimed to elucidate the macroscopic and microscopic distributions of the dorsal nerve of penis (DNP) that provides the greatest sensitivity over the glans penis. The glandes of 23 penises of formalin-embalmed cadavers were investigated to confirm the macroscopic and microscopic distributions of the DNP within the glans penis by whole-mount Sihler's staining and histological sectioning. Superficial regions of the mid-glans were reconstructed in three dimensions to define the microstructure of terminal branches of the DNP that project towards the skin surface. A mean of 6.7 bundles of the DNP consisting of several nerve fibres converged linearly towards the distal end of the penis, rather than diverging laterally as they travelled. Lateral branches of the DNP extended linearly to the distal end with ramifications, while dorsomedial branches of the DNP gave off nerve fibres to the dorsum of the mid-glans and the corona. The intrastromal ramifications of the DNP were more developed in the distal half of the glans penis than the proximal glans containing the corpus cavernosum. These ramifications gave rise to radial nerve fibres that project towards the skin surface to form a plexiform network of terminal branches in the dermis. Linear projections of the main branches of the DNP throughout the glans and fine networks of terminal branches in the dermis were distinctly visualized in the human penis.

Three-dimensional reconstruction of the luminal structure of human seminal vesicle.

The seminal vesicles are the glands of male reproductive organs that produce the fluid and nutrient constituents of semen. It has been believed for a long time that the lumen of a seminal vesicle was a single-coiled tubular structure with irregular diverticula. There are several previous reports on the symmetry, differences in morphological sizes and classification of the seminal vesicles. However, a three-dimensional-coiled tubular structure is difficult to understand using a classical anatomical methodology, and hence, three-dimensional reconstruction is needed to understand the structure of the lumen. Thirty-one seminal vesicles harvested from 21 formalin-embalmed cadavers were investigated. The seminal vesicle along with the ampulla of the ductus deferens was separated, and the length and width of each seminal vesicle were measured. The vesicles were then embedded in coloured paraffin, and the resulting paraffin block was sectioned transversely and photographed at an interval of 500 µm, with the sectioned surfaces then utilized in three-dimensional reconstruction performed by 'Reconstruct' software. The mean length and width of the seminal vesicles were 39.4 mm and 13.4 mm, respectively, and the right seminal vesicle was a little larger than the one on the left. The size differed from previous reports, while the luminal structure was similar to the classification of Aboul-azm (Archives of Andrology, 3, 1979, 287-292) but differed from that of Pereira (AJR. American Journal of Roentgenology, 69, 1953, 361-379). The seminal vesicles typically comprised about 9 curls and had about 12 diverticula. The seminal vesicles resembled a skein of coral rather than comprising a single strand. These findings will help in improving the understanding of pathophysiologies of the seminal vesicles, such as recurrent inflammation of the gland.

Effects of Reading a Free Electronic Book on Regional Anatomy with Schematics and Mnemonics on Student Learning.

BACKGROUND: To help medical students learn anatomy effectively in limited hours, a regional anatomy book enhancing students' memorization was developed. METHODS: Only anatomical terms essential for basic cadaver dissection are included along with schematic figures which enable memorization of complicated anatomical structures. Learning comics and comic strips that depict anatomy mnemonics and jokes were appended and sentences were written to be comfortably readable. The electronic book titled "Visually Memorable Regional Anatomy" has been distributed without payment or registration. With the help of 246 volunteer students from three Korean medical schools, the book's learning effects were evaluated. RESULTS: These students' book reading led to increase in their anatomy scores, including written examination scores and tag examination scores. It was an encouraging result that almost 20% of students spontaneously read the book no matter who presented their lecture or examination. A webpage version of the book was visited by thousands of users. CONCLUSION: The book with unique features may suggest a new perspective in the field of anatomy learning. After having acquaintance with essential structures from reading the book, students are able to and willing to study more from other resources.

Femoral nerve split with variant iliacus muscle: a potential source of femoral nerve entrapment.

The iliacus muscle is a large, flat, triangle-shaped muscle located in the iliac fossa. This muscle forms part of the iliopsoas muscle complex. Although anatomical variations of iliacus muscles are rare, some variations are clinically important due to the possible coexistence of an unusual course of the femoral nerve. The femoral nerve is the largest branch of the lumbar plexus and supplies the muscles and skin in the anterior aspect of the thigh. We encountered a case of a single aberrant slip of the iliacus muscle piercing the femoral nerve in the left iliac fossa of a male cadaver aged 97 years. The potential clinical importance of this variant iliacus muscle accompanied by a femoral nerve split would be femoral neuropathy and possible consequent alterations of sensation in the anterior and medial aspects of the thigh or motor deficit of the quadriceps muscle.

Ligamentous structures in human glans penis.

The corpus spongiosum reportedly occupies a larger proportion of the human glans penis than does the penile body, embedding the end of the corpus cavernosus (CC). However, anatomic descriptions about the fibrous structures of glans penis in the literature cause confusion during dissection and reconstructive surgery. Forty-five penises of formalin-embalmed cadavers were dissected sagittally along the course of the distal urethra and observed macroscopically. Dense connective tissues adjacent to the fossa navicularis and spongiosum parts of the glans were cropped, and underwent Masson's trichrome and Verhoeff-Van-Gieson staining. Most (55.5%) of the specimens had distinct fibrous bands toward the distal tips of the glans penis, which elongated from the tunica albuginea of the CC. They comprised longitudinal collagen bundles continuous to the outer longitudinal layer of the tunica albuginea covering the CC and were intermingled with sparse elastic fibres. This architecture either did not reach the distal end of the glans penis (35.5% of cases), or was obscure or dispersed in all directions (9.0% of cases). The structural dimorphism and the variations in the ratio of dense connective tissue components of the fibrous skeleton are considered to contribute to the varying degrees of flexibility, distensibility and rigidity of the human glans penis.

Consistency of the lateral canthus as an anatomic landmark and its clinical implications.

Successful oculofacial procedures require the availability of a reliable surgical and anatomic landmark. This study aimed to determine the usefulness of the lateral canthus as a surface landmark. Seventy-seven from 42 Korean cadavers were dissected. The horizontal distance from the lateral canthus to the lateral orbital margin and the vertical distances from the zygomaticofrontal suture and the inferior orbital margin to the lateral canthus were measured. The mean horizontal distance from the lateral canthus to the lateral orbital margin was 7.8 mm. Although the horizontal position of the lateral canthus appears to alter with age, the variation was only 2-3 mm. The mean vertical distances from the zygomaticofrontal suture and inferior orbital margin to the lateral canthus were 8.1 and 17.2 mm. The vertical position of the lateral canthus did not vary with age, being located inferiorly within a fingernail width from the zygomaticofrontal suture. The lateral canthus, which is easily accessible and supported by muscular and fibrous lateral orbital attachments, exhibits small anatomic variations. Thus, the lateral canthus could act as a reliable surface landmark for identifying the location of underlying structures and describing a lesion on the face. Clin. Anat. 32:630-634, 2019. © 2019 Wiley Periodicals, Inc.

Using the zygomatic arch as a reference line for clinical applications and anthropological studies.

PURPOSE: The Frankfurt line is the most frequently and widely used reference line in cephalometric analysis, but has shortcomings including the difficulty of landmark identification. This study investigated using the superior border of the zygomatic arch as a new external bony landmark, including measuring the angle between the new reference line and the Frankfurt line. METHODS: Facial computed tomography scans were obtained from 170 patients (100 males and 70 females) hospitalized at Konkuk University Chungju Hospital. After three-dimensional reconstruction, the locations of the porion and the inferior orbital rim and the superior border of the zygomatic arch were identified twice by two observers using software. A horizontal line parallel to the superior border of the zygomatic arch was established. The angle between the Frankfurt line and new reference line was then measured on each side. RESULTS: There was no significant intraobserver or interobserver bias. The angle between the Frankfurt line and the superior border of the zygomatic arch was 4.5° ± 2.5° (mean ± SD), and it was somewhat larger in females than males, but the difference was not statistically significant. CONCLUSIONS: This study demonstrated the good reproducibility of the location of the superior border of the zygomatic arch and found that the angle between the new reference line and the Frankfurt line is relatively constant. The superior border of the zygomatic arch therefore has potential as an alternative reference line to the Frankfurt line in specific clinical applications and anthropological studies, since it is a more accessible bony landmark on the external skull.

Asymmetric Protrusion of the Midface in Young Adults.

PURPOSE: This study evaluated midfacial asymmetry using an alternative method that involved comparing bilateral patterns of the zygomaticomaxillary prominence in a young adult population. MATERIALS AND METHODS: Three-dimensional reconstructed images based on computed tomography scans of 100 Koreans (mean age, 24.7 years) were evaluated with reference to lines spaced at 30° intervals and radiating from the center of an interporion line in a superior view. The surface inclination of the zygomaticomaxillary region was quantified on the same reference lines using a 3-dimensional ruler. RESULTS: The 30°-interval line (at the level of the zygomaticotemporal suture) was longer on the left side than the right side in both males and females, whereas the left 60°-interval line (at the level of the zygomaticofrontal suture) was longer in females. Comparing the surface protrusion revealed that the zygomaticomaxillary region was more prognathic and inflated on the left side. CONCLUSION: Functional deviations are considered to be causes of asymmetric craniofacial growth. Postnatal growth allometry across the circummaxillary sutures as elucidated by this study could be useful information in craniofacial surgery.

Surgical anatomy of the superficial temporal artery to prevent facial nerve injury during arterial biopsy.

To investigate the topographical relationship between the frontal branch of the superficial temporal artery (FSTA) and the temporal branch of the facial nerve (TFN) with the aim of preventing nerve injury during FSTA biopsy. Fifty-seven hemifaces of 33 cadavers were dissected. Vertical lines drawn to the lateral orbital margin (LOM) and the superior root of the helix were used as the anterior and posterior reference positions, respectively. Horizontal lines drawn through the supraorbital margin and lateral canthus were used as the superior and inferior reference points, respectively. The depth and course relationships of the FSTA and TFN were examined. Midpoints between the FSTA and TFN are situated approximately 6.0 and 4.5 cm posterior to the lateral orbital margin at the levels of the lateral canthus and supraorbital margin, respectively. The TFN is generally situated 1-2 cm anteriorly and inferiorly to the FSTA in the temporal region. However, in two cases (3.6%), the TFN ran just underneath the FSTA with only a very small safe distance, making it highly vulnerable to iatrogenic injury. In conclusion, when performing an FSTA biopsy, the surgeon should not dissect below the superficial temporal fascia because there is an overlap between the course of the FSTA and the TFN in a minority of cases. Also, surgical incisions should be made outside the area delineated by an oblique line passing through the points 6.0 and 4.5 cm posterior to the lateral orbital margin at the levels of the lateral canthus and the supraorbital margin, respectively. Clin. Anat. 31:608-613, 2018. © 2017 Wiley Periodicals, Inc.

Visualization of the tentorial innervation of human dura mater.

Posterior projections of the ophthalmic division of the trigeminal nerve (the ophthalmic nerve) are distributed in the tentorium cerebelli as recurrent meningeal branches. We investigated the morphological tentorial distribution of the ophthalmic nerve. Fifty-two sides of the tentorium cerebelli and adjacent dura mater obtained from 29 human specimens were stained using Sihler's method to examine the nerve fibres in the dural sheets. The innervation patterns of the tentorium cerebelli were classified into the following four types according to their distributions: Type 1, where nerve fibres projected to both the straight and transverse sinuses; Type 2, where nerve fibres projected only to the transverse sinus and lateral convexity; Type 3, where nerve fibres projected medially only to the straight sinus and the posterior part of the falx cerebri; and Type 4, where the nerve fibres terminated within the tentorium cerebelli. Images of the tentorium cerebelli were superimposed to identify areas of dense innervation. The incidence rates of Types 1-4 were 71.2% (n = 37), 21.2% (n = 11), 3.8% (n = 2) and 3.8% (n = 2), respectively. More branches of nerve fibres traversed towards the transverse sinus posterolaterally than towards the straight sinus medially. The space between the anterior half of the straight sinus and the medial tentorial notch can be considered a safe surgical area where innervation is scarce. The posterior part of the falx cerebri was innervated by the ophthalmic nerve that traversed to the straight sinus. The parietal branches of the middle meningeal artery in the lateral convexity that were projected orthogonally by the ophthalmic nerve traversed the transverse sinus, implicating their vulnerability and possible sensitivity under physiological or neurosurgical conditions. This study has revealed the macroscopic tentorial innervation of the dura mater in humans, which could be useful information for both neurosurgeons and neurologists.

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.

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.

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.