Morphological examination of abdominal vertebral bodies from grass carp using high‐resolution micro‐CT scans

Abstract

The vertebral column, a defining trait of all vertebrates, is organized as a concatenated chain of vertebrae, and therefore its support to the body depends on individual vertebral morphology. Consequently, studying the morphology of the vertebral centrum is of anatomical and clinical importance. Grass carp (GC) is a member of the infraclass Teleostei (teleost fish), which accounts for the majority of all vertebrate species; thus, its vertebral anatomical structure can help us understand vertebrate development and vertebral morphology. In this study, we have investigated the morphology and symmetry of the grass carp vertebral centrum using high‐resolution micro‐CT scans. To this end, three abdominal vertebrae (V9, V10, & V11) from eight grass carp were micro‐CT scanned and then segmented using Dragonfly (ORS Inc.). Grass carp vertebral centrum conformed to the basic teleost pattern and demonstrated an amphicoelous shape (biconcave hourglass). The centrum's cranial endplate was smaller, less circular, and shallower compared to the caudal endplate. While the vertebral centrum demonstrated bilateral symmetry along the sagittal plane (left/right), the centrum focus was shifted dorsally and cranially, breaking dorsoventral and craniocaudal symmetry. The sum of these findings implies that the caudal aspect of grass carp vertebral centrum is bigger and more robust. Currently, we have no information whether this is due to nature, for example, differences in gene expression, or nurture, for example, environmental effect. As the vertebral parapophyses and spinous processes are slanted caudally, the direction of muscle action during swimming may create a gradient of stresses from cranial to caudal, resulting in a more robust caudal aspect of the vertebral centrum. Expanding our study to include additional quadrupedal and bipedal (i.e., human) vertebrae, as well as testing if these morphological aspects of the vertebrae are indeed plastic and can be affected by environmental factors (i.e., temperature or other stressors) may help answer this question.

Anatomy, 3D micro-CT and Semiquantitative Elemental Microanalysis in Common carp vertebrae (Cyprinus carpio; Linnaeus, 1758)

“…The vertebral centrum of the Common carp aligns with the general morphological pattern observed in teleosts (Sakashita et al, 2019;Schultze & Arratia, 2013;Barak et al, 2024). It is crucial to recognize that the macroscopic structure of the vertebrae is not homogeneous and, as con rmed by histological studies, neither are the microscopic characteristics.…”

“…This morphological feature may be related to the need to withstand greater muscular tensions during swimming, creating a tension gradient that strengthens the caudal end of the centrum. These ndings, highlight the importance of considering the morphological and biomechanical variability of the spine in anatomical studies and for understanding the functional adaptation of cyprinids to their aquatic environment (Barak et al, 2024).…”

“…This pattern may be related to their role in supporting the ns and participating in caudal propulsion. Barak et al (2024) analyzed the morphology of the vertebrae of the grass carp, providing data that can be extrapolated to understand the vertebral structure in the Common carp. They report that the vertebral bodies exhibit an hourglass shape and asymmetry between the cranial and caudal ends, with the caudal end being more robust, suggesting a speci c adaptation to better withstand the forces generated during active swimming and caudal propulsion.…”

“…This selection was made to ensure that the results re ected general vertebral characteristics, independent of anatomical variations such as those in uenced by the shape of the head or tail. To identify and describe the vertebral segments, structural criteria related to the position of the ns and the speci c characteristics of the vertebrae in each segment were adopted according to Barak et al (2024). This approach facilitated a detailed exploration of the vertebral anatomy of the carp.…”

“…In the eld of biomechanics and vertebral anatomy, the Common carp exhibits unique characteristics in its spine that are crucial for detailed study. Recently, micro-computed tomography (micro-CT) was used to examine the morphology of the vertebral bodies (centrum) of grass carp (Ctenopharyngodon idella), highlighting their amphicoelous shape with concave terminal plates at both ends (Barak et al, 2024). The results showed that while the vertebral centrum presents bilateral symmetry in the sagittal plane, this symmetry is altered in the transverse plane.…”