Study on the Korean adult cranial capacity

Ancient to modern secular changes in the cranial/cephalic index in Korea: historical brachycephalization and recent debrachycephalization

We investigated changes in the cranial/cephalic index of the Korean population in millennia, centuries, and recent decades. Secular changes of Korean's cephalic index in history were studied using the data of archaeology literature and our measurement data of different adult skull sets for the fifteenth-nineteenth century Joseon people, the Korean War victims (1950-1953), and the Korean skeletons collected by medical schools in the 1960s. A change in head shape during the last century was also estimated by the analysis on Korean cephalometric datasets of Korean Research Institute of Standards and Science. In brief, over the past 2000 years, the crania of Korean people have steadily changed from mesocephalic to brachycephalic, mainly due to the cranial length shortening. Brachycephalization accelerated at the beginning of the twentieth century and continued until the early twenty-first century, largely caused by increased cephalic breadth. We also note that debrachycephalization began in birth cohorts around 1965 for males and around 1970 for females. Taken together, we figure out that the head shape of Korean people has been gradually shortened over millennia and then has undergone dramatic shortening in the last century. In recent decades, however, the changing pattern has reversed to debrachycephalization, for which we discussed about the possible causes in the present report.

A Cross-sectional Anthropometric Study of Cranial Capacity among Ukwuani People of South Nigeria

BACKGROUND

Cranial capacity is used as a measure of brain volume and has a relationship with age and gender. The purpose of this study was to provide normative data and population-, age- and gender-specific regression formulae related to cranial capacity using head dimensions among the Ukwuani people of Nigeria.

METHODS

This study included 605 subjects grouped according to age as follows: 6-12 years, 13-19 years and ≥20 years. A cross-sectional study design using multistage sampling technique was adopted. Head length, head width, and auricular head height were measured in centimetres using a spreading caliper, and cranial capacity was calculated. The data were analysed using SPSS 20. Descriptive and inferential statistics were applied. A t-test was used to identify significant gender differences. Regression analyses were performed to derive age-, gender- and population-specific models. P-values < 0.05 were considered significant.

RESULTS

In all the parameters, males had significantly higher values than females (P < 0.05). The mean (SD) cranial capacity values at 6-12 years, 13-19 years and ≥20 years were 1176.95 (98.35) cc, 1288.59 (113.21) cc and 1408.90 (116.44) cc, respectively.

CONCLUSIONS

All the parameters exhibited sexual dimorphism. Cranial capacity was found to increase with age. The models derived in this work will be relevant to population and growth studies as well as forensic anthropology.

MRI-based anatomical model of the human head for specific absorption rate mapping

In this study, we present a magnetic resonance imaging (MRI)-based, high-resolution, numerical model of the head of a healthy human subject. In order to formulate the model, we performed quantitative volumetric segmentation on the human head, using T1-weighted MRI. The high spatial resolution used (1 x 1 x 1 mm(3)), allowed for the precise computation and visualization of a higher number of anatomical structures than provided by previous models. Furthermore, the high spatial resolution allowed us to study individual thin anatomical structures of clinical relevance not visible by the standard model currently adopted in computational bioelectromagnetics. When we computed the electromagnetic field and specific absorption rate (SAR) at 7 Tesla MRI using this high-resolution model, we were able to obtain a detailed visualization of such fine anatomical structures as the epidermis/dermis, bone structures, bone-marrow, white matter and nasal and eye structures.

MRI-based volumetry of head compartments: Normative values of healthy adults

The size of head compartments (head and brain volume, intracranial volume, gray and white matter volume, cerebrospinal fluid volume) and their ratios were determined on the basis of magnetic resonance images of the head acquired in a reference population of 502 healthy subjects. Age-matched subgroups were selected to reveal gender-related differences and changes with age. Normative data are provided in the form of simple equations that allow transforming measured compartment volumes into z scores, offering the possibility to relate individual data to a larger population.

Relation between Intracranial Volume and the Surface Area of the Foramen Magnum

Several investigators have estimated the intracranial volume (ICV) in the past which indirectly reflects the brain volume. Most of these studies have been made on the dry skulls using linear dimensions, packing methods or occasionally radiological methods. It is also reported that the etiology of cerebellar tonsillar herniation is closely related to the size of the foramen magnum (FM). In the present study the ICVs have been estimated in 28 dry skulls using filling water method and the surface area of FMs were measured planimetry method. The estimated mean ICV was 1,311 +/- 133 cm. Surface area of FM was 760 +/- 144 mm. Antero-posterior and lateral direct roentgenograms of the skulls were also taken and the width, height and length (WHL) of the skull were measured by means of the cephalometry on radiograms. The relationship between the ICV, WHL and surface area of FM were analyzed statistically. The ICV, WHL and surface area of FM was correlated well (r = 0.271, P < 0.005; r = 0.265, P < 0.005, respectively) and a regression formula was proposed. Our results showed that skulls with larger ICV and WHL have larger FM surface area. We also suggested a regression formula that could be used to predict the surface area of FM regarding to the ICV and WHL values. In the next step, we took roentgenograms of skulls and obtain ICV measuring the width, length and height of skulls by means of cephalometry and investigate the relation between the findings of cephalometry and surface area of FM. The cephalometry could apply on living subjects and, thereby, our findings could provide some data to evaluate the etiology of Arnold Chiari malformation and achondroplasia for living subjects.