The different growth zones of the fetal foot

Visualization of the dentogingival junction using micro-plastination technique

Plastination has revolutionized the field of anatomy and research by providing biosecurity and enabling the long-term preservation of biological material, ranging from entire bodies to individual organs and even micron sections. The dentogingival junction (DGJ) consists of both epithelial and connective tissues that are closely related to the tooth's mineralized tissues. Cutting-grinding techniques are commonly used to visualize DGJ histology. These techniques exclude enamel from preparations and focus on visualizing hard or soft tissues. To improve the micro-anatomical and histological study of this region, we applied micro-plastination technique to obtain micro-thin slices below 150 μm thick from human and animal samples. The DGJ microanatomy was visualized by applying histological stains to the micro-plastinated slices, highlighting the technique's endogenous autofluorescence capacity identifying periodontal tissues, including dentin, enamel, cementoenamel junction, dentinal tubules, connective tissue, and collagen. Based on our results, we confirm that micro-plastination is a useful technique for visualizing anatomical regions that are difficult to access, such as the DGJ. Micro-plastination can be used as an alternative technique, providing a new approach for its application in anatomical and morphological research protocols.

The development of the medial longitudinal arch in the intrauterine period

In this study, we aimed to reveal whether the medial longitudinal arch is formed in the intrauterine period and the structural features of the medial longitudinal arch. The study was conducted on 146 feet of 73 fetuses (38 male, 35 female) aged between 15 and 40 weeks of gestation. The fetuses were grouped by trimesters. The footprints taken were photographed with a millimeter ruler, and the development of the medial longitudinal arch was examined on footprints based on the Clarke index, Chipaux-Smirak index, and Staheli index. In Clarke index and Staheli index, it was observed that the arch height was normalized in the transition from the second trimester to the third trimester, the arch decreased in the transition to full-term, and the rate of pes planus increased. All indices detected pes planus by 81.81% in the full-term period. The rate of pes planus determined according to Clarke index and Staheli index, especially in the third trimester period, was 6.94% and 11.11%, respectively. We have provided a perspective on how the development of the medial longitudinal arch is shaped in the intrauterine period. Based on the results of study, we consider that the data on the medial longitudinal arch, especially in the third trimester period, may be more significant. In the evaluations made from the footprints of premature infants in the intrauterine third trimester period in the future, a study, in which infants detected with pes planus can be followed up and the development of their medial longitudinal arch is evaluated, can be conducted.

Micro-magnetic resonance imaging and embryological analysis of wild-type and pma mutant mice with clubfoot

Gross similarities between the external appearance of the hind limbs of the peroneal muscle atrophy (pma) mouse mutant and congenital talipes equinovarus (CTEV), a human disorder historically referred to as ‘clubfoot’, suggested that this mutant could be a useful model. We used micro-magnetic resonance imaging to visualize the detailed anatomy of the hind limb defect in mutant pma mice and performed 3D comparisons between mutant and wild-type hind limbs. We found that the pma foot demonstrates supination (i.e. adduction and inversion of the mid foot and fore foot together with plantar flexion of the ankle and toes) and that the tibiale and distal tarsals display 3D abnormalities in positioning. The size and shape of the tibia, fibula, tarsal and metatarsal bones are similar to the wild-type. Hypoplasia of the muscles in the antero-lateral (peroneal) compartment was also demonstrated. The resemblance of these features to those seen in CTEV suggests that the pma mouse is a possibly useful model for the human condition. To understand how the observed deformities in the pma mouse hind foot arise during embryonic development, we followed the process of foot rotation in both wild-type and pma mutant mice. Rotation of the hind foot in mouse embryos of wild-type strains (CD-1 and C57/Black) occurs from embryonic day 14.5 onwards with rotation in C57/Black taking longer. In embryos from both strains, rotation of the right hind foot more commonly precedes rotation of the left. In pma mutants, the initiation of rotation is often delayed and rotation is slower and does not reach completion. If the usefulness of the pma mutant as a model is confirmed, then these findings on pma mouse embryos, when extrapolated to humans, would support a long-standing hypothesis that CTEV is due to the failure of completion of the normal process of rotation and angulation, historically known as the ‘arrested development hypothesis’.

Three-dimensional reconstruction of the ankle by means of ultrathin slice plastination

Computerized reconstruction of anatomical structures is becoming very useful for developing anatomical teaching modules and animations. Although databases exist consisting of serial sections derived from frozen cadaver material, plastination represents an alternate method for developing anatomical data useful for computerized reconstruction. Plastination is used as an excellent tool for studying different anatomical and clinical questions. The sheet plastination technique is unique because it offers the possibility to produce transparent slices series, which can easily be processed morphometrically. The purpose of this study was to describe a method for developing a computerized model of the human ankle using plastinated slices. This method could be applied to reconstruct any desired region of the human body.A human ankle was obtained, plastinated, sectioned, and subjected to 3D computerized reconstruction using WinSURF modeling system (SURFdriver Software). Qualitative observations revealed that the morphological features of the model were consistent with those displayed by typical cadaveric specimens. Morphometric analysis indicated that the model did not significantly differ from a sample of cadaveric specimens. These data support the use of plastinates for generating tissues sections useful for 3D computerized modeling.