U-Young Lee

Identification using frontal sinus by three-dimensional reconstruction from computed tomography.

Abstract:  Radiographs and computed tomography (CT) images have been increasingly applied and accepted in forensic sciences. Along with radiographs and CT images, the frontal sinus is often used for the individual identification because of its unique and unchangeable characteristics. The purpose of this study is to define the usefulness of three‐dimensional (3‐D) images of the frontal sinus for identification. CT images from 119 Korean cadavers were built up for 3‐D reconstruction and surveyed with 15 measurements. The total volume of the sinus, some nonmetric characteristics, and the bilateral asymmetry index in men differed significantly from those in women (p < 0.05). The digit codes, six sections and 10‐digit number, were almost able to accurately identify individuals (98%). This study showed a statistical difference between the sexes and classified the fused and prominent middle sinuses for the first time. This proposed method for identification is more accurate than those used in other studies.

Morphological characteristics of the infraorbital foramen and infraorbital canal using three-dimensional models

Infraorbital nerve blocking through the infraorbital foramen and infraorbital canal is used to anesthetize the lower eyelid, upper lip, lateral nose, upper teeth and related gingivae. For this, it is important to know the position of the infraorbital foramen, structures around the foramen, and the direction of the injecting needle related to the angle of the infraorbital canal. Many reports have described the anatomical location of the infraorbital foramen; however, not many have described the angle of the infraorbital canal and those structures around the infraorbital foramen that help the physician visualize the correct direction of the needle. Dried skulls of 42 Korean subjects (27 male and 15 female) were studied to analyze structures around the infraorbital foramen. The morphology of the infraorbital canal was also investigated using three-dimensional models. Structures around the infraorbital foramen were classified into four types according to the existence of a distinct tuberosity above the infraorbital foramen, and the degree of prominence of the canine fossa. Types I and II have a tuberosity above the infraorbital foramen, whereas types III and IV have no distinct tuberosity. Types I and III have a prominent canine fossa, whereas this is less prominent in types II and IV. We analyzed the skulls based on the angle of the infraorbital canal to the median plane. We compared the left and right sides and analyzed differences between the sexes, the three canal shapes, and the four structure types around the infraorbital foramen. Type IV was the most common in this series (38%). The infraorbital canal could be classified into three morphologies: ‘tube-like’ (69%), ‘funnel’ (25%) and ‘pinched’ (6%). The mean angle of the infraorbital canal relative to the median plane was 12°, and the angle relative to the Frankfurt plane was 44°. The mean angle between the infraorbital canal and the Frankfurt plane was 4° larger in males than in females in this series of Korean subjects. The operator of the infraorbital nerve block should pay attention towards directing the needle upward at an angle of about 44° for avoiding nerve damage and consider the different angles of the canal according to the individual’s sex.

Microscopic Age Estimation from the Anterior Cortex of the Femur in Korean Adults

Abstract:  The purpose of this study was to develop age‐predicting equations from the anterior cortex of the femur of Korean adults. Seventy‐two femoral samples (44 male and 28 female) were obtained from Korean cadavers and used to develop the equations. The thin sections (<100‐μm thick) were prepared by manual grinding; the sections were not decalcified and were stained with Villanueva bone stain reagent. Analysis of covariance showed no significant differences in age‐adjusted histomorphological variables between sexes. In stepwise regression analysis, osteon population density, average osteon area, and the most anterior cortical width were selected for an age‐predicting equation which produced a high regression correlation (R2 = 0.789). The average Haversian canal area was not significantly related to age for any specimen.

Determination of sex for the 12th thoracic vertebra by morphometry of three-dimensional reconstructed vertebral models.

Abstract:  Thirty‐three linear measurements and two ratios were derived from 102 12th thoracic vertebrae of the Digital Korean database at the Catholic Institute for Applied Anatomy. Of 35 linear traits, 23 were sexually dimorphic. We created 23 discriminant function equations that predicted sex with 62.7–85.3% accuracy. The analysis using combinations of two factors gave higher accuracies: most equations with accuracies over 80% included at least one measurement involving the coronal diameter of the vertebral endplate. Using stepwise method of discriminant function analysis, three variables predicted sex with 90.0% accuracy: the coronal diameter of the superior endplate of the vertebral body, the ratio of anterior to middle height of the body, and the length of the left mammillary process and pedicle. Coronal dimensions of the vertebral body represented the major sex difference. These equations will help forensic discrimination of the sex of this vertebra among Koreans.

Sex determination from calcaneus in Korean using discriminant analysis.

The calcaneus can be used for the differentiation of sex and populations using discriminant function equations. This bone has been used for sex determination in some population groups, but it has not been used for sex determination in Koreans until now. The purpose of this study was to develop discriminant function equations for sex determination from the calcaneus in modern Koreans and prove the need for population-specific discriminant function equations. The sample consisted of 104 calcanei from modern Korean cadavers, and 10 variables were measured for each. All variables showed statistically significant sexual differences (P<0.05) and generated a large effect size (Cohens d>0.9). The accuracy ranged from 65.4 to 89.4%, the highest accuracy was when all variables were used in the direct method. In dimensional groups, the length dimensional group had the highest accuracy (84.6%), and MINB (body of calcaneus) and MAXL (maximum calcaneal length) could be used as a single measurement. Most Korean females were misclassified as males using the equations of other population groups, and this finding demonstrates the necessity of population-specific equations.

Sex determination using discriminant analysis of upper and lower extremity bones: New approach using the volume and surface area of digital model

This study used 110 CT images taken from donated Korean cadavers to create 3-D models of the following upper and lower limb bones: the clavicle, scapula, humerus, radius, ulna, hip bone (os coxa), femur, patella (knee cap), tibia, talus, and calcaneus. In addition, the bone volume and surface area were calculated to determine sex differences using discriminant analysis. Significant sex differences were found in all bones with respect to volume and surface area (p<0.01). The order of volume was the same in females and males (femur>hip bone>tibia>humerus>scapula), although the order of surface area was different. The largest surface area in men was the femur and in women was the hip bone (p<0.01). An interesting finding of this study was that the ulna is the bone with the highest accuracy for sex determination (94%). When using the surface area of multiple bones, the maximum accuracy (99.4%) was achieved. The equation was as follows: (discriminant equation of surface area; female<0<male)=0.060×clavicle+0.020×scapula+0.045×humerus+(-0.049)×radius+0.093×ulna+(-0.023)×hip bone+0.091×patella+(-0.052)×fibula+0.043×talus-11.548. These results show that bone volume and surface area of extremity bones can be used for sex determination.

Sex determination from the mandibular ramus flexure of Koreans by discrimination function analysis using three-dimensional mandible models

It has been known that mandible ramus flexure is an important morphologic trait for sex determination. However, it will be unavailable when mandible is incomplete or fragmented. Therefore, the anthropometric analysis on incomplete or fragmented mandible becomes more important. The aim of this study is to investigate the sex-discriminant potential of mandible ramus flexure on the Korean three-dimensional (3D) mandible models with anthropometric analysis. The sample consists of 240 three dimensional mandibular models obtained from Korean population (M:F; 120:120, mean age 46.2 y), collected by The Catholic Institute for Applied Anatomy, The Catholic University of Korea. Anthropometric information about 11 metric was taken with Mimics, anthropometry libraries toolkit. These parameters were subjected to different discriminant function analyses using SPSS 17.0. Univariate analyses showed that the resubstitution accuracies for sex determination range from 50.4 to 77.1%. Mandibular flexure upper border (MFUB), maximum ramus vertical height (MRVH), and upper ramus vertical height (URVH) expressed the greatest dimorphism, 72.1 to 77.1%. Bivariate analyses indicated that the combination of MFUB and MRVH hold even higher resubstitution accuracy of 81.7%. Furthermore, the direct and stepwise discriminant analyses with the variables on the upper ramus above flexure could predict sex in 83.3 and 85.0%, respectively. When all variables of mandibular ramus flexure were input in stepwise discriminant analysis, the resubstitution accuracy arrived as high as 88.8%. Therefore, we concluded that the upper ramus above flexure hold the larger potentials than the mandibular ramus flexure itself to predict sexes, and that the equations in bivariate and multivariate analysis from our study will be helpful for sex determination on Korean population in forensic science and law.

Axonal Synapses Utilize Multiple Synaptic Ribbons in the Mammalian Retina

In the mammalian retina, bipolar cells and ganglion cells which stratify in sublamina a of the inner plexiform layer (IPL) show OFF responses to light stimuli while those that stratify in sublamina b show ON responses. This functional relationship between anatomy and physiology is a key principle of retinal organization. However, there are at least three types of retinal neurons, including intrinsically photosensitive retinal ganglion cells (ipRGCs) and dopaminergic amacrine cells, which violate this principle. These cell types have light-driven ON responses, but their dendrites mainly stratify in sublamina a of the IPL, the OFF sublayer. Recent anatomical studies suggested that certain ON cone bipolar cells make axonal or ectopic synapses as they descend through sublamina a, thus providing ON input to cells which stratify in the OFF sublayer. Using immunoelectron microscopy with 3-dimensional reconstruction, we have identified axonal synapses of ON cone bipolar cells in the rabbit retina. Ten calbindin ON cone bipolar axons made en passant ribbon synapses onto amacrine or ganglion dendrites in sublamina a of the IPL. Compared to the ribbon synapses made by bipolar terminals, these axonal ribbon synapses were characterized by a broad postsynaptic element that appeared as a monad and by the presence of multiple short synaptic ribbons. These findings confirm that certain ON cone bipolar cells can provide ON input to amacrine and ganglion cells whose dendrites stratify in the OFF sublayer via axonal synapses. The monadic synapse with multiple ribbons may be a diagnostic feature of the ON cone bipolar axonal synapse in sublamina a. The presence of multiple ribbons and a broad postsynaptic density suggest these structures may be very efficient synapses. We also identified axonal inputs to ipRGCs with the architecture described above.

Left lobe hypoplasia of the human liver: a report of two cases

Two cases of left lobe hypoplasia of the human liver were dissected minutely to show the intrahepatic vessels and ducts. In the left side of the round ligament, one case had a large cyst-like mass containing dilated vessels and ducts, while the other was accompanied by three rugby-ball-like parenchymal masses, each of which was covered by the peritoneum. The former specimen carried the usual Spiegel’s lobe, while the latter was very small. Fascial and peritoneal fusion was evident at and around these two left lobes. In both cases the left hepatic vein showed the usual course and terminal end, segment IV was present to a greater or lesser degree. Thus, we hypothesized that, due to fascial and peritoneal fusion, membranous stricture occurred at the peripheral portions of the left portal trunk and left hepatic duct. The discussion focuses on a comparison of intrahepatic vascular configurations in four recently reported cases, including the present two livers.

Anthropological Age Estimation with Bone Histomorphometry from the Human Clavicle

Abstract The purpose of present study was to apply histomorphometry to estimate the age at death using the clavicular osteonal remodeling rate and to develop an age-predicting equation. 46 clavicular samples consisting 28 males and 18 females were obtained from Korean cadavers. Two sequential 1-mm-thick sections, were prepared using a diamond wheel, and a 100 um-thick section was then made by manual grinding with polarizing filter optical microscopy. Three histomorphometric variables, including relative cortical area (RCA), osteon population density (OPD), and mean osteon area (OA), were measured. The mean values are indicated because no significant difference in any variable was noted by a paired t test between the two sequential sections. Analysis of covariance demonstrated that stratification of the statistical results of OPD and OA based on sex was unnecessary, except for RCA. Regression analysis indicated that the highest coefficient value was OPD (R2 = 0.583), which was selected as a significant value with RCA for an age-predicting equation (R2 = 0.628) by the multiple regression analysis stepwise method. In conclusion, a histomorphometric method using the clavicle is reliable for age estimation in physical and forensic anthropological fields.