Perpendicular Research Articles

Congenital Internal Auditory Canal Stenosis

A 3-year-old boy underwent evaluation for possible cochlear implantation. He had failed a neonatal otoacoustic emission (OAE) hearing screen. A combined auditory brainstem response/auditory steady-state response (ABR/ASSR) test battery confirmed the presence of a severe hearing loss on the right and a profound hearing loss on the left. No Joint Committee on Infant Hearing (JCIH) risk factors for early childhood hearing loss1 were identified. Rehabilitation via hearing aid amplification and auditory-verbal speech therapy was unsuccessful. Computerized tomographic (CT) imaging of the temporal bone was performed to identify the presence of any inner ear abnormalities. No abnormalities of the cochlea, vestibule and semicircular canals on both sides were identified by the radiologist. The internal auditory canals were described as “fairly symmetrical without widening”, and the study was officially reported as an “unremarkable study of the temporal bones”. Independent review of the CT imaging revealed the presence of seemingly narrow internal auditory canals (IAC) on both sides. (Figure1A) The width of the IACs on the axial plane were measured by drawing a perpendicular line starting from the posterior wall of the IAC, 2 mm inside the posterior lip of the internal auditory meatus, and ending on the anterior canal wall, as described by McClay et al.2 Measurements taken utilizing the length measurement tool in the DICOM imaging software (RadiAnt DICOM Viewer, Version 2024.1, Medixant) indicated an IAC width of 1.78 mm on the right (with severe hearing loss) and 1.37 mm on the left (with profound hearing loss). (Figure 1B) These measurements confirmed the presence of bilateral internal auditory canal stenosis, a diagnosis defined by a canal of 2 mm or less on highresolution CT.3

Application of surface landmark positioning in assisting cone-beam CT scanning of temporomandibular joint

Objective: To quantitatively measure the spatial relationship between the temporomandibular joint (TMJ) and surface landmarks such as the tragus and lateral canthus using cone-beam CT (CBCT), as to provide guidance for accurate positioning of CBCT scanning of the TMJ. Methods: DICOM format data from 112 patients (35 males and 77 females with 224 TMJs) were included in this study. The patients were between 12 and 66 years old, with a mean age of (25.6±9.81) years and they underwent initial visits at the Department of Stomatology, The First Medical Center, Chinese PLA General Hospital. CBCT images were imported into Mimics Medical 21.0 software for three-dimensional reconstruction. The distance between selected surface landmarks and corresponding projection points on the same side of the TMJ were measured in both the sagittal and coronal planes. In the frontal view, the distance from the lateral canthus to the perpendicular line passing through the center of the condyle (dx); in the lateral view, the vertical distance from the horizontal line through the rear edge convex of tragus to the roof of glenoid fossa (dy1); the vertical distance from the horizontal line through the rear edge convex of tragus to sigmoid notch (dy2); the distance from the tragus to the perpendicular line through the center of the condyle (dz). The results were compared between different genders and age groups (adolescent group aged 12 to 18 years, 33 cases; adult group aged>18 years, 79 cases). To verify the reliability and stability of the body surface landmarks obtained in this study, a comparison was made between the use of scout view positioning and the auxiliary positioning method that utilizes body surface landmarks to capture the mandibular condyle in a small field of view CBCT of the TMJ (scout view group, 25 cases; surface landmark-assisted positioning group, with 25 cases aged 12-18 years and 25 cases older than 18 years, totaling 50 cases), with regard to the deviation distance from the central point of the field of view to the central point of the mandibular condyle. Results: A total of 112 patients with 224 TMJs were included in this study. In the frontal view, dx was (8.59±3.13) mm, with no significant difference between the left and right sides, between males and females (P>0.05). Notably, the dx in the adolescent group [(7.43±3.02) mm] was significantly smaller than that in the adult group [(9.07±3.06) mm] (t=-3.68, P<0.001). In the lateral view, dy1 was (14.80±3.90) mm, showing no significant difference between the left and right sides, males and females, or different age groups(P>0.05). Similarly, dy2 was (6.82±3.95) mm, with no significant differences between the left and right sides or between males and females(P>0.05). However, the dy2 in the adolescent group [(5.88±4.13) mm] was significantly smaller than that in the adult group [(7.22±3.83) mm] (t=-2.33, P=0.021). Regarding dz, the measurement was (11.73±3.16) mm, with no significant difference between the left and right sides, between males and females (P>0.05). Meanwhile, the dz in the adolescent group[(10.92±2.74) mm] was also significantly smaller than that in the adult group [(12.07±3.27) mm] (t=-2.52, P=0.012). The verification results showed that both positioning methods could fully display the TMJ. The eccentricity in the scout view group [(8.84±3.79) mm ]was slightly greater than that in the body surface landmark-assisted positioning group[ (6.50±2.88) mm], and the difference between the two groups was statistically significant (t=4.20, P=0.032). Conclusions: The TMJ can be accurately positioned using stable surface landmarks such as the tragus and lateral canthus for reference.

Liver anatomy for totally laparoscopic segment 7 resection from a caudal magnified view-a 3-dimensional computed tomographic analysis.

Laparoscopic resection of hepatic segment 7 is considered particularly difficult. We analyzed anatomic variation of this segment in caudally oriented 3-dimensional (3D) magnified computed tomographic (CT) images obtained prior to liver resection. Analysis included 105 patients with preoperative 3D CT evaluation preceding liver resection for hepatobiliary malignancies between April 2021 and April 2024. Five ramification patterns were evident from a caudal magnified view. Some patients who had multiple segment 7 (S7) portal pedicles and an S7 pedicle branching ventrally posed difficulty in performing segmentectomy for the exact extent of S7. Distance from the point where a perpendicular line from the right rim of the inferior vena cava (IVC) intersected the right posterior portal pedicle to the point of bifurcation of the S6 and 7 pedicles was 34.6mm (range, 3.9-78.8; mean ± standard deviation, 35.2 ± 14.8mm). The median angle between the perpendicular line from the right rim of the IVC and the line from the root of the S7 pedicle to the right rim of the IVC was 77° (10-140); the mean ± standard deviation was 75.3° ± 28.1. Differences among ramification patterns also were evident. The angle between the right posterior portal pedicle and the S7 pedicle was 143° (79-215) or 143.3 ± 26.7, and that between S7 and S6 pedicles was 71°(15-123) or 75.5 ± 21.7°, representing relatively little variation. Understanding these details of caudal-view anatomy may resolve difficulties and clarify access required for exposing S7 portal pedicles.

Anteroposterior axis of the tibia for kinematic aligned total knee arthroplasty.

It is not known where the anatomical axis of rotation on the tibial side will be in kinematic alignment (KA), a rapidly expanding area of total knee arthroplasty (TKA) alignment technique today. The purpose of this study was to define the tibial axis for KA-TKA. Fifty patients who underwent computed tomography (CT) examination of the lower extremities at a single institution were included. The posterior condylar axis (PCA) and surgical epicondylar axis (SEA) were identified in the CT axial view and projected onto the tibial slice. The respective perpendicular lines that pass through was attachment of the posterior cruciate ligament (PCL) were identified as the anatomic axis of rotation of the tibia relative to the PCA and SEA, and the position of each axis of rotation. Furthermore, the relationship of these perpendicular lines with the Akagi line was evaluated. The axis of tibial rotation to the SEA was similar to that of the Akagi line; the axis of tibial rotation to the PCA was located approximately 2.9° medial to the Akagi line, and when the origin of the tibial axis was set at the PCL attachment site, the intersection point of the tibial axis was approximately 2.5 mm medial to the medial border of the tibial tuberosity. The distribution of tibial axis had a wide range. Although there is a large individual variation, the average tibial axis for KA-TKA is 2.9° more internally rotated than the Akagi line. Level IV.

Effect of surface orientation on the corrosion behavior of Ni-based single-crystal alloy in a simulated marine atmosphere at 750 °C

DD5 single-crystal alloy samples with different surface orientations were obtained by machining the alloy ingot perpendicular (PP) and parallel (P), respectively, to its solidification direction (SD). The corrosion behaviors of the PPSD and PSD alloy samples were investigated in the atmosphere of moist air + NaCl aerosol at 750 °C. Results showed that during initial corrosion, γ′ phase developed a thin NiO layer with Al internal corrosion product. However, a NiO nodule with an internal Cr2O3 layer was formed on γ phase. As corrosion progressed, the corrosion product gradually grew to a NiO/(Al, Cr)2O3 bilayer, accompanied by internal corrosion consisting of Al2O3. It was also found that the PSD sample with a lower fraction and smaller size of γ’ phases exhibited better corrosion resistance than the PPSD sample. The effect of alloy surface orientation on the corrosion mechanism was discussed.

Long-term computed tomographic osteolytic analysis of highly cross-linked polyethylene prosthesis after total hip arthroplasty

To analyze the occurrence of osteolysis in total hip arthroplasty (THA) with highly cross-linked polyethylene prosthesis during a follow-up of more than 15 years. The clinical data of 84 patients (105 hips) treated with THA in the Affiliated Hospital of Kanazawa Medical University in Japan between June 2000 and April 2004 and met the selection criteria was retrospectively analyzed. There were 7 males and 77 females, aged from 41 to 75 years, with an average of 56.4 years. There were 94 hips with secondary hip osteoarthritis, 4 hips after pelvic osteotomy, 2 hips with primary hip osteoarthritis, 2 hips with traumatic hip osteoarthritis, 2 hips with osteonecrosis of the femoral head, and 1 hip with rheumatoid arthritis. According to Crowe classification, there were 79 hips of type Ⅰ, 19 hips of type Ⅱ, 6 hips of type Ⅲ, and 1 hip of type Ⅳ. The highly cross-linked polyethylene acetabular liner combined with a 26 mm zirconia femoral head were used in all patients. X-ray films were taken after operation to analyze the radiation transmission and osteolysis around the acetabular prosthesis. The vertical distance (the distance between the teardrop line at the lower edge of the pelvis and the perpendicular line of the hip rotation center), the horizontal distance (the horizontal distance between the hip rotation center and the interteardrop line and the vertical line at the lower edge of the teardrop), and the acetabular cup anteversion angle were measured at last follow-up. The acetabular and femoral osteolysis was analyzed by CT scan and three-dimensional multiplanar reconstruction (3D-MPR). Combined with X-ray film and CT results, osteolysis was evaluated according to the Narkbunnam score. Deep vein thrombosis of lower limbs occurred in 2 cases. All patients were followed up 15-18 years, with an average of 15.9 years. One hip dislocation and 1 periprosthetic fracture occurred postoperatively, and no acetabular loosening or prosthetic lining ruptures occurred. Except for 1 patient who had a radiolucent line in the acetabulum after operation, the other 83 patients did not show any radiolucent line in the acetabulum or the femur. None of the patients underwent hip revision. X-ray films at last follow-up showed an acetabular cup anteversion angle of -10°-39°, with an average of 22°; a vertical distance of 3.5-47.1 mm, with an average of 24.6 mm; and a horizontal distance of 22.6-48.1 mm, with an average of 31.7 mm. There was no acetabular or femoral osteolysis in all patients on X-ray films and CT 3D-MPR images at last follow-up, and the Narkbunnam score was 0 in any region. Highly cross-linked polyethylene prosthesis does not increase the risk of long-term complications such as osteolysis after THA.

A comparative study of the efficacy of customized titanium plates versus conventional maxillary protraction in the treatment of skeletal class Ⅲ patients

Objective: To compare the clinical efficacy of customized titanium plate and conventional maxillary protraction treatment in patients with skeletal class Ⅲ malocclusion during growth spurt. Methods: During growth spurt, skeletal class Ⅲ patients with maxillary hypoplasia who were treated in the Department of Orthodontics, Capital Medical University School of Stomatology from August 2018 to July 2021 were prospectively enrolled. They were treated with maxillary protraction using customized titanium plates (customized titanium plate group) and conventional methods (conventional protraction group), respectively. Lateral cephalometric radiographs were collected before and after treatment for conventional cephalometric analysis, including SNA angle (angle between Sella, Nasion and A point), ANB angle (angle between A point, Nasion, and B point), FH-MP angle (mandibular plane angle), Y-axis angle, U1-L1 angle (upper to lower central incisor angle), U1-SN angle (upper incisor to SN plane angle), anterior and lower height, maxillary length, etc. The stable basicranial line (SBL) was used as the reference line to measure the distance from each reference point (ANS point, A point, Prn point, Sn point, UL point etc.) to the stable basicranial vertical line (VerT, the perpendicular line of the skull base line at the intersection point of the anterior wall of the sella image and the inferior edge of the anterior bed process). Paired t-tests were performed on the cephalometric data before and after maxillary protraction treatment in the two groups, and two independent samples t-tests were performed to compare the differences in the efficacy of the two maxillary protraction methods. Results: A total of 20 patients (9 males and 11 females), aged (10.8±1.3) years, were included in the personalized titanium plate group. A total of 20 patients (8 males and 12 females), aged (10.5±1.1) years, were included in the conventional protraction group. The SNA angle, ANB angle, FH-MP angle, Y-axis angle, anterior lower height, maxillary length, ANS-VerT distance, A-VerT distance, Prn-VerT distance, Sn-VerT distance, and UL-VerT distance were significantly higher than those before treatment in the two groups (P<0.05). The changes of SNA angle, ANB angle and A-VerT before and after treatment in the personalized titanium plate group [3.15°±2.28°, 4.64°±1.40°, (4.41±3.43) mm, respectively] were significantly higher than those in the traditional group [2.13°±2.69°, 2.81°±1.10°, (3.13±4.76) mm, respectively](P<0.05), and the changes of U1-L1 angle and U1-SN angle before and after treatment (-0.76°±7.42° and 1.74°±6.38°, respectively) was significantly lower than that of the control group (-5.14°±6.62° and 4.57°±5.24°, respectively, P<0.05). Conclusions: Maxillary protraction can effectively improve skeletal class Ⅲ relationships in growing patients. The linear measurements using the SBL line as a reference plane visualize the sagittal improvement in sagittal relationship after maxillary protraction. The customized titanium plate maxillary protraction treatment has a clear therapeutic effect on patients with skeletal class Ⅲ deformities, and its dental effect is relatively small.

Integrated modeling of anisotropic neutron yields of classical and spherical tokamaks

Estimations of counting rates of neutron spectrometers in experiments on controlled fusion with magnetic confinement, as well as calculations of energy resolved flux densities of fusion neutrons from plasma to the walls of a reactor require spatial integration of the local, usually anisotropic function of the neutron source. The integrated modeling consists of three main stages. First, sources of fast particles in beam- or wave-heated plasma are calculated. The next stage deals with spatial, energetic, and angular velocity distributions of plasma ions. Finally, double differential rate coefficients of nuclear fusion reactions are computed. This article describes calculations of spatial distributions of nuclear fusion reaction rates in classical and spherical tokamaks and the anisotropy of the neutron yield and spectra. The results are based on analytical formulas for energetic and angular distributions of the local source of fusion products in plasma. Examples of energetic spectral densities of neutron fluxes on first walls are presented, as well as energy resolved counting rates of collimated neutron spectrometers for perpendicular and tangential lines of sight.

Beaton and Anson Type A Classification of the Sciatic Nerve and Piriformis Complex: Clinical Considerations for Sex and Laterality

Variations of the sciatic nerve and piriformis muscle (SN-PM) relationship must be considered when discussing orthopedic procedures within the region as they may cause increased risk of SN injuries. Thirty-one formalin-embalmed, prosected donors were evaluated using the Beaton and Anson (B&amp;A) classification system (1939). Major landmarks of the SN-PM relationship were identified, including the posterior superior iliac spine (PSIS), ischial tuberosity (IT), greater trochanter (GT), and the middle of the SN as it exits under the PM (S1). Distances measured included: PSIS-IT, PSIS-GT, IT-GT, PSIS-S1, IT-S1, GT-S1, S1-Q (distance of perpendicular line connecting S1 to PSIS-IT), and S1-R (distance of perpendicular line connecting S1 to PSIS-GT). Measurements from 49 lower extremities were evaluated using a two-tailed t-test to compare by sex and laterality; a one-tailed t-test was utilized to compare groups based on anatomical sex. Six donors displayed asymmetric B&amp;A classifications, demonstrating gross anatomical differences within a single individual; however, no measurements were significant when comparing extremities. Seven measurements were statistically significant (p &lt; 0.05) between sexes, indicating notable sex-based differences. These data highlight sex-based differences in the SN-PM relationship, as well as consistencies within measurements among extremities, which can be utilized by clinicians when treating male and female patients needing unilateral or bilateral orthopedic procedures or injections within the gluteal region.

Mathematics E-learning Packets for Technical and Livelihood Education (TLE) Automotive Servicing

This study aimed to develop and evaluate Mathematics e-learning packets tailored for Technical and Livelihood Education (TLE) Automotive Servicing students at a public national high school, in the City Schools Division of Marikina for the School Year 2023-2024. The impetus for the study was based on the increasing number of learners who are having difficulty solving basic mathematical problems. The research addressed the following questions: (1) identifying Mathematics 9 topics suitable for e-learning packets based on literature review, (2) evaluating the developed packets by automotive and mathematics teachers according to DepEd guidelines concerning content quality, instructional quality, technical quality, assessment, visuals, and plan layout, (3) assessing any significant differences between the evaluations of the two groups of respondents, and (4) gathering comments and suggestions for improvement. Utilizing a descriptive research method, the study involved evaluations from 15 mathematics teachers and 15 automotive teachers from two public national high schools in Marikina City, Philippines. Data were analyzed using Weighted Mean and the Mann-Whitney U Test. Key findings include (1) prioritized topics under the Matatag Curriculum: perpendicular and parallel lines, relations and functions, quadratic functions and equations, direct and inverse variations, trigonometric ratios, and probability of simple events; (2) both groups rated the e-learning packets highly acceptable, with grand weighted means of 3.50 and 3.60, respectively; (3) no significant difference was found between the evaluations of the two groups; (4) respondents praised the packets' adequacy, organization, relevance, and interactivity, offering suggestions to incorporate more visuals, expand topics and activities, add video demonstrations, and involve industry professionals. In conclusion, the developed e-learning packets were well-received and deemed effective, with recommended enhancements aimed at further enriching the learning experience and bridging theoretical knowledge with practical application.

A novel theory for rapid localization of the transverse-sigmoid sinus junction and “keyhole” in the retrosigmoid keyhole approach: micro-anatomical study, technique nuances, and clinical application

To determine a rapid and accurate method for locating the keypoint and “keyhole” in the suboccipital retrosigmoid keyhole approach. (1) Twelve adult skull specimens were selected to locate the anatomical landmarks on the external surface of the skull.The line between the infraorbital margin and superior margin of the external acoustic meatus was named the baseline. A coordinate system was established using the baseline and its perpendicular line through the top point of diagastric groove.The perpendicular distance (x), and the horizontal distance (y) between the central point of the “keyhole” and the top point of the digastric groove in that coordinate system were measured. The method was applied to fresh cadaveric specimens and 53 clinical cases to evaluate its application value. (1) x and y were 14.20 ± 2.63 mm and 6.54 ± 1.83 mm, respectively (left) and 14.95 ± 2.53 mm and 6.65 ± 1.61 mm, respectively (right). There was no significant difference between the left and right sides of the skull (P > 0.05). (2) The operative area was satisfactorily exposed in the fresh cadaveric specimens, and no venous sinus injury was observed. (3) In clinical practice, drilling did not cause injury to venous sinuses, the mean diameter of the bone windows was 2.0–2.5 cm, the mean craniotomy time was 26.01 ± 3.46 min, and the transverse and sigmoid sinuses of 47 patients were well-exposed. We propose a “one point, two lines, and two distances” for “keyhole” localization theory, that is we use the baseline between the infraorbital margin and superior margin of the external acoustic meatus and the perpendicular line to the baseline through the top point of the digastric groove to establish a coordinate system. And the drilling point was 14.0 mm above and 6.5 mm behind the top point of the digastric groove in the coordinate system.

Describing the Anatomic Variability of the Dorsal Sulcus of the Distal Radius

Objectives Dorsal extensor tendon rupture is a known complication of volar locking plate fixation for treating distal radius fractures. Tenosynovitis or even tendon rupture secondary to dorsal screw protrusion has been reported in numerous case studies. The high anatomic variability in this area, along with difficulty in imaging the necessary anatomic detail, leads to inaccurate screw measurements. A detailed understanding of the dorsal anatomy of the distal radius may reduce future events. The purpose of this study is to describe a dorsal ulnar sulcus of the distal radius that can hide dorsal screw penetration and thus act as a blind spot to standard oblique radiographic images. Methods After obtaining approval from our Institutional Review Board, 59 consecutive magnetic resonance images of different wrists were analyzed. Using the axial cut with the maximum sulcus depth, a line was drawn from the apex of Lister’s tubercle to the dorsal ulnar corner of the radius. A perpendicular line was then drawn from this line to the deepest point in the sulcus. This measurement was recorded as sulcus depth. Results A sulcus was found in 97% (57/59) of individuals with an average depth of 1.3mm. The sulcus measured greater or equal to 2mm in 14% (8/59) of the wrists studied. The radiocarpal joint averaged 6.1 ± 2.9 mm distal to the sulcus measurement location. There was no significant difference between gender or extremity side regarding sulcus depth. Conclusion The dorsal ulnar blind spot is a clinically relevant sulcus on the dorsum of the distal radius. This region demonstrated variable depth in our study and is not easily quantified using standard radiographs. With heightened awareness of the anatomic variability of the dorsal sulcus, we reduced the incidence of dorsal tendon irritation at our institution to 0%. Therefore, caution should be taken when placing volar screws to prevent dorsal cortex penetration and subsequent extensor tendon injury. Level of Evidence 4

A study on the morphology of iliac crest based on the objectives of jaw bone defect reconstruction.

to understand the morphological characteristics of iliac crest and provide advice and assistance for jaw bone reconstruction with iliac bone flap by evaluating the thickness and curvature of iliac crest. 100 patients who had taken Spiral CT of the Abdominal region before surgeries between 2020 and 2022 were included in this study. 3D reconstruction images of the iliac bones were created. 5 vertical planes perpendicular to the iliac crest were made every 2cm along the centerline of the iliac crest (VP2 ~ VP10). On these vertical planes, 4 perpendicular lines were made every 1cm along the long axis of the iliac crest (D1 ~ D4). The thicknesses at these sites, horizontal angle (HA) of iliac crest and the distance between inflection point and the central point of anterior superior iliac spine (DIA) were measured. The thickness of iliac bone decreased significantly from D1 ~ D4 on VP6 ~ VP10 and from VP2 ~ VP10 on D3 and D4 level (P<0.05). HA of iliac crests was 149.13 ± 6.92°, and DIA was 7.36 ± 1.01cm. Iliac bone thickness, HA and DIA had very weak or weak correlation with patient's age, height and weight. The average thicknesses of iliac crest were decreased approximately from front to back, from top to bottom. The thickness and curvature of the iliac crest were difficult to predict by age, height and weight. Virtual surgical planning is recommended before jaw bone reconstruction surgery with iliac bone flap, and iliac crest process towards alveolar process might be a better choice.

Prediction of Distal Femoral and Posterior Articular Surfaces in Total Knee Arthroplasty With Severe Bone Defects Using Computed Tomography-Based Templating Software.

Introduction Optimal repair of the joint line (JL) in total knee arthroplasty (TKA) is critical for knee joint motion reconstruction and ligament balance. Identification of JL may be difficult, particularly in revision or primary cases of severe femoral condylar bone loss. We aimed to define the relationship between the epicondyles and the articular surface (AS) of the femur using computed tomography-based three-dimensional digital templating software. Methods The study included 127 knees with osteoarthritis of the knee below grade 2 on the Kellgren-Lawrence index. A perpendicular line was drawn from the medial and lateral femoral epicondylar processes to the most distal point of the AS, and the distance was measured in the axial and coronal planes. Femoral width was measured as the distance between the medial and lateral epicondyles. All distances described above were converted to a ratio by division with femoral width. Results On the axial plane, the distance from epicondyles to the posterior ASs was 29.4 ± 2.2 mm medially and 21.3 ± 2.1 mm laterally. The width of the distal femur was 75.2 ± 4.2 mm. On the coronal plane, the distances from epicondyles to the distal ASs were 25.2 ± 2.9 mm on the medial side and 21.3 ± 2.5 mm on the lateral side. The ratio of the distance from epicondyles to the distal and posterior ASs divided by the width of the femur was 0.39 ± 0.02, 0.28 ± 0.03, 0.34 ± 0.03, and 0.28 ± 0.03. Conclusions The distance from the epicondyles to the distal and posterior JLs correlates with the distal femur width. These findings may be useful in determining an appropriate JL.

The Isosceles Nasal Tip-Laser-Assisted Midline Assessment in Rhinoplasty.

The accurate determination of the nasal tip's spatial location is crucial for achieving symmetry in rhinoplasty. Even minor deviations can result in asymmetrical lengths and configurations of the nostrils. Our approach centers on defining the nasal tip position by establishing the midline of the nasal base and projecting an isosceles triangle. This triangle, with the tip as the vertex and alar creases as angles, ensures symmetric sidewalls. The symmetry axis, derived from the isosceles triangle, guides the placement of the tip sidewalls and columella. To implement this, we use anatomical benchmarks such as the implantation of the nasal base and position of the alar creases, considering inherent facial asymmetries. We introduce a laser gadget as an auxiliary tool, projecting perpendicular lines to guide precise midline alignment. Marking specific points, including interbrow midpoint and alar creases, ensures accuracy. In the past 12 months, we applied this methodology in 247 rhinoplasty cases, observing improved outcomes and patient satisfaction. Our proposal of utilizing isosceles triangles provides a streamlined approach to achieving symmetry. The laser device, while beneficial, should be viewed as supportive rather than an absolute guiding measure.

Anatomical Landmarks for Transverse-Sigmoid Sinus Junction: A Cadaveric Study.

Accurately identifying and avoiding crucial anatomical structures within the posterior cranial fossa using superficial landmarks is essential for reducing surgical complications. Our study focuses on the top of the mastoid notch (TMN) as an external landmark of the cranium, aiming to assist in the strategic placement of the initial burr hole. In this study, we present a method for predicting the path of the transverse sinus (TS) and explore the relationship between the junction of the transverse-sigmoid sinus and the TMN. Following anatomical dissections of the brain in cadaveric specimens, we conducted intracranial drilling from the inside surface of the cranium on 10 adult skulls (20 sides). A coordinate system was established on the posterolateral surface of the skull to assist the analysis. Using a self-leveling laser level, we set up a horizontal Frankfurt line (X-axis) and identified a vertical perpendicular line passing through the TMN to serve as the Y-axis. To identify the course of the TS, we divided the segment between the two inferomedial points into six equidistant points along the Frankfurt line. No significant difference was observed between the inferomedial points of the transverse-sigmoid sinus junction (TSSJ) on the left and right sides. The inferomedial point was positioned at a median of 6.6 mm (Q1: 3.7 mm, Q3: 9.4 mm) dorsally and at a median of 19.2 mm (Q1: 16.1 mm, Q3: 23.2 mm) cranially from the TMN. The upper edge of the TS was located at distances of 6.4 mm (5.7; 12.7), 10.3 mm (8.8; 12.3), and 13.8 mm (11.9; 16.3) on the right, and 4.9 mm (4.1; 7.9), 8.6 mm (7.6; 13.0), and 12.8 mm (11.7; 17.5) on the left side from the Frankfurt horizontal plane at the ¼, ½, and ¾ line points, respectively. The bottom edge was positioned at distances of 0.6 mm (-2.7; 2.0), 2.1 mm (-0.8; 3.8), and 4.8 mm (2.4; 6.7) on the right, and 1.1 mm (-3.4; 2.4), 2.0 mm (0.2; 4.8), and 3.9 mm (3.7; 5.3) on the left from these respective points. The upper edge of the right TS was found to be statistically more distant from the Frankfurt horizontal plane at the ¼ line point (p-value = 0.027) compared to that on the left side. The confluence of the sinus center was identified as having a median distance of 7.8 mm (4.5; 8.3) and an inferior point of 1.5 mm (0.1; 3.0) cranially to the inion. In all examined bodies (n = 10), the confluens sinuum was consistently 4.7 mm (3.3; 5.6) to the right in relation to the inion. Notably, the median of the right transverse sinus diameter (median = 9.3 mm) was found to be significantly larger than that of the left transverse sinus (median = 7.0), with a statistically significant p-value of 0.048. The literature regarding the external identification of the TSSJ and the course of the TS varies. In our efforts to provide a description, we have utilized the TMN as a reliable landmark for locating the TSSJ. To delineate the trajectory of the TS after its exit from the confluence of sinuses, we employed a Frankfurt horizontal plane to the inion. These findings may assist surgeons by using external skull landmarks to identify intracranial structures within the posterior fossa, particularly when image guidance devices are not available or to complement a neuronavigational system.

The femoral anterior tangent line could serve as a reliable alternative reference axis for distal femoral rotational alignment in total knee arthroplasty: an MRI-based study.

This study aimed to evaluate the reference value of the femoral anterior tangent (FAT) line as a guidance of distal femoral rotation on magnetic resonance images (MRI). We retrospectively included 81 patients (106 knees) diagnosed as ailing from primary knee osteoarthritis. The indirect rotational axes including the FAT line, the perpendicular line to the anteroposterior axis (pAPA), and the posterior condylar axis (PCA) were identified on MRI, and their angles related to the clinical transepicondylar axis (cTEA) or surgical transepicondylar axis (sTEA) were measured. The patients were further divided into subgroups according to the Kellgren-Lawrence (K-L) grades, the joint-line convergence angle (JLCA), and the arithmetic hip-knee-ankle angle (aHKA) to assess the variance of different rotational reference axes. The FAT line was -11.8° ± 3.6° internally rotated to the cTEA and -7.5° ± 3.6° internally rotated to the sTEA. The FAT/cTEA angle and the FAT/sTEA angle shared a similar frequency distribution pattern but a little greater variance to the pAPA/cTEA angle and the PCA/cTEA angle. The PCA/cTEA angle in the JLCA |x| ≥ 6° subgroup was significantly smaller than in the two other JLCA subgroups. The pAPA/cTEA angle and the PCA/cTEA angle also presented statistical significance within the aHKA subgroups. While the FAT/cTEA angle and the FAT/sTEA angle demonstrated superior stability among the different K-L grades, JLCA subgroups, and aHKA subgroups. The FAT line was less affected by the degree of knee osteoarthritis and lower limb alignment, which could serve as a reliable alternative reference axis for the distal femoral rotational alignment in total knee arthroplasty.

Preoperative Arithmetic Hip-Knee-Ankle Angle as a Predictor of Postoperative Leg Alignment in Medial Oxford Unicompartmental Knee Arthroplasty.

Introduction This study aimed to evaluate whether the arithmetic hip-knee-ankle angle (aHKA) can be used to predict the postoperative HKA. Methods This study included 248 knees in 166 patients who underwent Oxford unicompartmental knee arthroplasty (UKA) between February 2021 and November 2022. Through preoperative and postoperative long-leg radiography, the medial proximal tibial angle (MPTA) and the lateral distal femoral angle (LDFA) were expressed as the deviation from the perpendicular line to the mechanical axes, and the mechanical HKA (mHKA) was defined as the angle between the femoral and tibial mechanical axes. Using the MPTA and LDFA, the arithmetic HKA (aHKA; MPTA + LDFA) and the joint line obliquity (JLO; MPTA - LDFA) were calculated, and the preoperative and postoperative values were compared. Results The preoperative aHKA and the postoperative mHKA values were similar (-0.38° ± 2.96°) and significantly smaller than the difference between the preoperative and postoperative mHKAs (4.58° ± 3.60°, P < 0.05). Meanwhile, the MPTA tended to be varus, and the LDFA tended to be valgus. Eventually, the JLO inclined more medially from -6.33° ± 3.42° preoperatively to -8.97° ± 3.92° postoperatively, representing a significant difference (P < 0.05). Conclusion The preoperative aHKA was similar to the postoperative mHKA. Therefore, it can be regarded as a predictor of postoperative leg alignment after Oxford UKA. Meanwhile, there was a medial incline of the joint line. Further investigation is required to evaluate the effect of such a joint line alteration.

Evaluation of Scapular Dynamics in Sports Trainees

Background: The scapula provides stability and mobility for efficient upper-limb movement. Optimal scapular kinematics are essential for efficient force generation and injury prevention. Sports trainees, particularly those involved in sports requiring repetitive or high-intensity shoulder movements, are susceptible to injuries and performance limitations if associated with aberrant scapular mechanics. Understanding the intricacies of scapular dynamics is essential for designing tailored training interventions that enhance athletic performance. Rationale and objectives: Previous research has emphasized the need for sports-specific training protocols. The measurement of scapular rotation has gained significant attention. Evaluating asymmetries in scapular dynamics across various sports trainee populations is a step forward for the need for tailored interventions and injury prevention strategies in preventing injury and planning better exercise programs. The study uses a PALM meter for the measurement of scapular rotation. Methodology: 40 Subjects 19 to 24 years old from the sports authority of Andhra Pradesh, India, were studied after obtaining written informed consent. Scapular rotation measured in a neutral and with hands on the hip position. Root of the scapula (RSS), inferior angle of the scapula (IAS), and spinous processes (Sp) of C7 to T8 are taken as the anatomical landmarks. Measurements of scapular position taken in two arm positions: shoulder neutral, hands on hip. A right-angle triangle created by dropping a perpendicular line from the scapula's root to intersect the horizontal line between the scapula's inferior angle and the thoracic spine's closest spinous process (IAS-Sp). The hypotenuse represents the distance IAS to RSS, while the side opposite the angle θ is the distance IAS-Sp minus RSS-Sp. A positive result indicates upward scapular rotation, while a negative result indicates downward scapular rotation. Results and Conclusion: This cross-sectional study revealed variations in scapular rotation and the distances from spinous processes in the scapular position in neutral and hands-on Hip positions from right to left and male to female. Further studies are required to understand scapular rotation variations concerning various sports involving overhead activity, heavy weight lifting, endurance sports and anatomical variations, muscle activation patterns, or task demands. KEYWORDS: Scapular Rotation, Sports Trainees, Shoulder Movements, Scapular Mechanics, Athletic Performance.

Community structure of sea cucumber (Echinodermata: Holothuroidea) resources in the Kepulauan Seribu National Park, Indonesia

Abstract. Helmiyani NA, Suryanti S, Purwanti F. 2024. Community structure of sea cucumber (Echinodermata: Holothuroidea) resources in the Kepulauan Seribu National Park, Indonesia. Biodiversitas 25: 344-354. Kepulauan Seribu National Park has several types of commercial sea cucumbers (Echinodermata: Holothuroidea). Many local and foreign communities take sea cucumbers from nature without paying attention to habitat conditions. This phenomenon causes a decrease in the availability of sea cucumbers. This research was carried out to help stabilize the sea cucumber ecosystem and its availability to be considered for its sustainability. This research was conducted in May-June 2023, at Kelapa Dua Island and Panjang Kecil Island in the Kepulauan Seribu National Park, Jakarta, Indonesia. Sampling was carried out using the field observation method, where the location points were determined by adjusting where the sea cucumber habitat was located. Sampling points were carried out on two islands, each island was assigned 4 station points, with the total number of stations on both islands being 8 station points. Sampling was carried out using perpendicular transect lines, divided into 3 zones. The data analyzed includes the Index of Diversity, Evenness, Dominance and Density. Based on the results 12 species were obtained from both islands, with the genera Holothuria, Stichopus, Bohadschia, Actinopyga, and Synapta. The highest density is at station 3 Kelapa Dua Island, with a density value of 0.57 (ind/m2), and the lowest density is at station 1 Panjang Kecil Island with a value of 0.14 (ind/m2). The results show a moderate diversity value, a low Dominance value, and a small evenness value, while the water quality result value can be said to be good because it has a value according to the survival quality standards for sea cucumbers in marine waters.