Trunk musculature in Urodela species varies by habitat. In this study, trunk musculature was examined in five species of adult salamanders representing three different habitats: aquatic species, Amphiuma tridactylum and Necturus maculosus; semi-aquatic species, Cynops pyrrhogaster; terrestrial species, Hynobius nigrescens and Ambystoma tigrinum. More terrestrial species have heavier dorsal and ventral trunk muscles than more aquatic forms. By contrast, the lateral hypaxial musculature was stronger in more aquatic species. The number of layers of lateral hypaxial musculature varied among Urodela species and did not clearly correlate with their habitats. The M. rectus abdominis was separated from the lateral hypaxial musculature in both terrestrial and semi-aquatic species. In aquatic species, M. rectus abdominis was not separated from lateral hypaxial musculature. Lateral hypaxial musculature differed in thickness among species and was relatively thinner in terrestrial species. In more terrestrial species, dorsal muscles may be used for stabilization and ventral flexing against gravity. Ventral muscle may be used in preventing dorsally concave curvature of the trunk by dorsal muscles and by weight. The lengthy trunk supported by limbs needs muscular forces along the ventral contour line in more terrestrial species. And, the locomotion on well-developed limbs seems to lead to a decrease of the lateral hypaxial musculature.
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http://dx.doi.org/10.1292/jvms.13-0211 | DOI Listing |
J Anat
November 2024
Experimental Zoology Group, Wageningen University, Wageningen, The Netherlands.
Most teleost fish propel themselves with lateral body waves powered by their axial muscles. These muscles also power suction feeding through rapid expansion of the mouth cavity. They consist of muscle segments (myomeres), separated by connective tissue sheets (myosepts).
View Article and Find Full Text PDFDev Biol
February 2024
Department of Anatomy and Molecular Embryology, Ruhr University Bochum, Bochum, Germany. Electronic address:
In vertebrates, the lateral body wall muscle formation is thought to be initiated by direct outgrowth of the dermomyotomes resulting in the elongation of the hypaxial myotomes. This contrasts with the formation of the muscles of the girdle, limbs and intrinsic tongue muscles, which originate from long-range migrating progenitors. Previous work shows that the migration of these progenitors requires CXCR4 which is specifically expressed in the migrating cells, but not in the dermomyotome.
View Article and Find Full Text PDFVet Anaesth Analg
January 2024
Department of Comparative, Diagnostic, and Population Medicine, College of Veterinary Medicine, University of Florida, Gainesville, FL, USA.
Objective: To develop an ultrasound-guided caudal quadratus lumborum block (C-QLB) technique in canine cadavers and to compare sensory and motor blockade resulting from the combination of ultrasound-guided greater ischiatic notch (GIN) plane and C-QLB approaches (GIN-CQLB group) versus a lumbosacral plexus (LSP group) approach [combination of lateral pre-iliac (LPI) and parasacral (PS) techniques] in dogs.
Study Design: Descriptive anatomical study and prospective randomized, blinded, experimental crossover trial.
Animals: A total of six canine cadavers and six adult Beagle dogs.
Front Neurosci
January 2023
Department of Neuroanatomy and Embryology, Fukushima Medical University, Fukushima, Japan.
Due to its long history, the study of human gross anatomy has not adequately incorporated modern embryological findings; consequently, the current understanding has often been incompatible with recent discoveries from molecular studies. Notably, the traditional epaxial and hypaxial muscle distinction, and their corresponding innervation by the dorsal and ventral rami of the spinal nerve, do not correspond to the primaxial and abaxial muscle distinction, defined by the mesodermal lineages of target tissues. To resolve the disagreement between adult anatomy and embryology, we here propose a novel hypothetical model of spinal nerve ramification.
View Article and Find Full Text PDFDev Dyn
October 2022
Instituto Gulbenkian de Ciência, Oeiras, Portugal.
Background: The turtle carapace is an evolutionary novelty resulting from changes in the processes that build ribs and their associated muscles in most tetrapod species. Turtle embryos have several unique features that might play a role in this process, including the carapacial ridge, a Myf5 gene with shorter coding region that generates an alternative splice variant lacking exon 2, and unusual expression patterns of Lbx1 and HGF.
Results: We investigated these turtle-specific expression differences using genetic approaches in mouse embryos.
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