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Journal of Morphology Jul 2018The development of the tetrapod pectoral and pelvic girdles is intimately linked to the proximal segments of the fore- and hindlimbs. Most studies on girdles are...
The development of the tetrapod pectoral and pelvic girdles is intimately linked to the proximal segments of the fore- and hindlimbs. Most studies on girdles are osteological and provide little information about soft elements such as muscles and tendons. Moreover, there are few comparative developmental studies. Comparative data gleaned from cleared-and-stained whole mounts and serial histological sections of 10 species of hylid frogs are presented here. Adult skeletal morphology, along with bones, muscles, and connective tissue of both girdles and their association with the proximal portions of the anuran fore- and hindlimbs are described. The data suggest that any similarity could be attributable to the constraints of their ball-and-socket joints, including incorporation of the girdle and stylopodium into a single developmental module. An ancestral state reconstruction of key structures and developmental episodes reveals that several development events occur at similar stages in different species, thereby preventing heterochronic changes. The medial contact of the halves of the pectoral girdle coincides with the emergence of the forelimbs from the branchial chamber and with the total differentiation of the linkage between the axial skeleton and the girdles. The data suggest that morphogenic activity in the anterior dorsal body region is greater than in the posterior one, reflecting the evolutionary sequence of the development of the two girdles in ancient tetrapods. The data also document the profound differences in the anatomy and development of the pectoral and pelvic girdles, supporting the proposal that the pectoral and pelvic girdles are not serially homologous, as was long presumed.
Topics: Anatomy, Comparative; Animals; Anura; Forelimb; Hindlimb; Organogenesis; Phylogeny; Species Specificity
PubMed: 29665044
DOI: 10.1002/jmor.20820 -
Ecology and Evolution Oct 2020Frogs and toads (Lissamphibia: Anura) show a diversity of locomotor modes that allow them to inhabit a wide range of habitats. The different locomotor modes are likely...
Frogs and toads (Lissamphibia: Anura) show a diversity of locomotor modes that allow them to inhabit a wide range of habitats. The different locomotor modes are likely to be linked to anatomical specializations of the skeleton within the typical frog Bauplan. While such anatomical adaptations of the hind limbs and the pelvic girdle are comparably well understood, the pectoral girdle received much less attention in the past. We tested for locomotor-mode-related shape differences in the pectoral girdle bones of 64 anuran species by means of micro-computed-tomography-based geometric morphometrics. The pectoral girdles of selected species were analyzed with regard to the effects of shape differences on muscle moment arms across the shoulder joint and stress dissipation within the coracoid. Phylogenetic relationships, size, and locomotor behavior have an effect on the shape of the pectoral girdle in anurans, but there are differences in the relative impact of these factors between the bones of this skeletal unit. Remarkable shape diversity has been observed within locomotor groups indicating many-to-one mapping of form onto function. Significant shape differences have mainly been related to the overall pectoral girdle geometry and the shape of the coracoid. Most prominent shape differences have been found between burrowing and nonburrowing species with headfirst and backward burrowing species significantly differing from one another and from the other locomotor groups. The pectoral girdle shapes of burrowing species have generally larger moment arms for (simulated) humerus retractor muscles across the shoulder joint, which might be an adaptation to the burrowing behavior. The mechanisms of how the moment arms were enlarged differed between species and were associated with differences in the reaction of the coracoid to simulated loading by physiologically relevant forces.
PubMed: 33144978
DOI: 10.1002/ece3.6784 -
Journal of Morphology Mar 2015Acipenseriformes hold an important place in the evolutionary history of bony fishes. Given their phylogenetic position as extant basal Actinopterygii, it is generally...
Acipenseriformes hold an important place in the evolutionary history of bony fishes. Given their phylogenetic position as extant basal Actinopterygii, it is generally held that a thorough understanding of their morphology will greatly contribute to the knowledge of the evolutionary history and the origin of diversity for the major osteichthyan clades. To this end, we examined comparative developmental series from the pectoral girdle in Acipenser fulvescens, A. medirostris, A. transmontanus, and Scaphirhynchus albus to document, describe, and compare ontogenetic and allometric differences in the pectoral girdle. We find, not surprisingly, broad congruence between taxa in the basic pattern of development of the dermal and chondral elements of the pectoral girdle. However, we also find clear differences in the details of structure and development among the species examined in the dermal elements, including the clavicle, cleithrum, supracleithrum, posttemporal, and pectoral-fin spine. We also find differences in the internal fin elements such as the distal radials as well as in the number of fin rays and their association with the propterygium. Further, there are clear ontogenetic differences during development of the dermal and chondral elements in these species and allometric variation in the pectoral-fin spine. The characters highlighted provide a suite of elements for further examination in studies of the phylogeny of sturgeons. Determining the distribution of these characters in other sturgeons may aid in further resolution of phylogenetic relationships, and these data highlight the role that ontogenetic and comparative developmental studies provide in systematics.
Topics: Animal Fins; Animals; Bone and Bones; Cartilage; Clavicle; Fishes; Phylogeny
PubMed: 25303307
DOI: 10.1002/jmor.20328 -
Developmental Dynamics : An Official... Oct 2020Two main theories have been used to explain the origin of pectoral and pelvic appendages. The "fin-fold theory" proposes that they evolved from a trunk bilateral fin... (Review)
Review
Two main theories have been used to explain the origin of pectoral and pelvic appendages. The "fin-fold theory" proposes that they evolved from a trunk bilateral fin fold, while Gegenbaur's theory assumes they derived from the head branchial arches. However, none of these theories has been fully supported. The "fin-fold" theory is mainly often accepted due to some existing developmental data, but recent developmental studies have revived Gegenbaur's theory by revealing common mechanisms underlying the patterning of branchial arches and paired appendages. Here I review developmental data and many others lines of evidence, which lead to a crucial question: might the apparent contradictions between the two theories be explained by a dual origin of the pectoral appendage, that is, the pectoral girdle and fin/limb being mainly related to the head and trunk, respectively? If this is so then (a) the pectoral and pelvic girdles would not be serial homologues; (b) the term "developmental serial homologues" could only potentially be applied to the pectoral and pelvic fins/limbs. Fascinatingly, in a way this would be similar to what Owen had already suggested, more than 170 years ago: that the pectoral and pelvic girdles are mainly related to the head and trunk, respectively.
Topics: Animal Fins; Animals; Biological Evolution; Extremities; Fishes; Fossils; Gene Expression Profiling; Gene Expression Regulation, Developmental; Gene Regulatory Networks; Gills; Humans; Mice; Phylogeny; Urodela
PubMed: 32395826
DOI: 10.1002/dvdy.192 -
Autopsy & Case Reports Nov 2020There is scant information about the comprehensive distribution of dystrophic muscles in muscular dystrophy. Despite different clinical presentations of muscular...
There is scant information about the comprehensive distribution of dystrophic muscles in muscular dystrophy. Despite different clinical presentations of muscular dystrophy, a recent multi-center study concluded that phenotypic distribution of dystrophic muscles is independent of clinical phenotype and suggested that there is a common pattern of involved muscles. To evaluate this possibility, the present case report used cadaveric dissection to determine the whole-body distribution of fat-infiltrated, dystrophic muscles from a 72-year-old white male cadaver with adult-onset, late-stage muscular dystrophy. Severely dystrophic muscles occupied the pectoral, gluteal and pelvic regions, as well as the arm, thigh and posterior leg. In contrast, muscles of the head, neck, hands and feet largely appeared unaffected. Histopathology and a CT-scan supported these observations. This pattern of dystrophic muscles generally conformed with that described in the multi-center study, and provides prognostic insight for patients and the physicians treating them.
PubMed: 33344329
DOI: 10.4322/acr.2020.221 -
Clinical Anatomy (New York, N.Y.) Mar 2023Knowledge of musculoskeletal anatomy is fundamental to physical therapy education. Although detailed anatomy syllabi have been developed for medical and other health...
Knowledge of musculoskeletal anatomy is fundamental to physical therapy education. Although detailed anatomy syllabi have been developed for medical and other health professional students, none are available for training physical therapists. Therefore, the aim of this project was to produce a core musculoskeletal anatomy syllabus specific to physical therapy students, utilizing a modified Delphi approach. An international Delphi panel (n = 53) composed of anatomists and clinicians involved in physical therapy education considered a total of 2193 anatomical items arranged in four categories (musculoskeletal concepts; vertebral column; pectoral girdle and upper limb; pelvic girdle and lower limb). Using specific criteria, items were rated on the basis of whether they were considered essential knowledge for a competent physical therapy student, and were categorized as core, recommended, not recommended or not core. Of the 2193 items, 1700 (77.5%) were rated as core or recommended. For musculoskeletal concepts, 70% (233/332) of items were categorized as core/recommended. Approximately 80% of items in the other three categories were considered core/recommended-vertebral column (355/440), pectoral girdle and upper limb (513/657), and pelvic girdle and lower limb (599/764). This project presents a detailed musculoskeletal anatomy syllabus which may be used within a physical therapy curriculum. A key difference compared to published musculoskeletal anatomy syllabi for medical students is that a greater number of items are considered core/recommended (approximately 80% vs. 50%). These findings will now be considered and deliberated in accordance with the International Federation of Associations of Anatomists modified Delphi approach.
Topics: Humans; Curriculum; Education, Medical, Undergraduate; Students, Medical; Anatomists; Spine; Anatomy
PubMed: 36177764
DOI: 10.1002/ca.23953 -
Journal of the American Veterinary... Jan 2022To determine the prevalence of pectoral girdle fractures in wild passerines found dead following presumed window collision and evaluate the diagnostic accuracy of...
OBJECTIVE
To determine the prevalence of pectoral girdle fractures in wild passerines found dead following presumed window collision and evaluate the diagnostic accuracy of various radiographic views for diagnosis of pectoral girdle fractures.
SAMPLE
Cadavers of 103 wild passerines that presumptively died as a result of window collisions.
PROCEDURES
Seven radiographic projections (ventrodorsal, dorsoventral, lateral, and 4 oblique views) were obtained for each cadaver. A necropsy was then performed, and each bone of the pectoral girdle (coracoid, clavicle, and scapula) was evaluated for fractures. Radiographs were evaluated in a randomized order by a blinded observer, and results were compared with results of necropsy.
RESULTS
Fifty-six of the 103 (54%) cadavers had ≥ 1 pectoral girdle fracture. Overall accuracy of using individual radiographic projections to diagnose pectoral girdle fractures ranged from 63.1% to 72.8%, sensitivity ranged from 21.3% to 51.1%, and specificity ranged from 85.7% to 100.0%. The sensitivity of using various combinations of radiographic projections to diagnose pectoral girdle fractures ranged from 51.1% to 66.0%; specificity ranged from 76.8% to 96.4%.
CLINICAL RELEVANCE
Radiography alone appeared to have limited accuracy for diagnosing fractures of the bones of the pectoral girdle in wild passerines after collision with a window. Both individual radiographic projections and combinations of projections resulted in numerous false negative but few false positive results.
Topics: Animals; Fractures, Bone; Passeriformes; Radiography; Scapula
PubMed: 34986113
DOI: 10.2460/javma.20.11.0642 -
Anatomical Record (Hoboken, N.J. : 2007) Feb 2023As one of the mysteries volant vertebrates, pterosaurs were completely extinct in the K-Pg extinction event, which hampered our understanding of their flight. Recent...
As one of the mysteries volant vertebrates, pterosaurs were completely extinct in the K-Pg extinction event, which hampered our understanding of their flight. Recent studies on pterosaur flight usually use birds as analogies, since their shoulder girdle share many features. However, it was also proposed that these two groups may differ in some critical flight mechanisms, such as the primary muscles for the upstroke of the wings. Here, we describe and characterize the detail features of the pectoral girdle morphology and histology in Hamipterus from the Early Cretaceous of Northwest China for the first time. Our research reveals that the scapula and coracoid of Hamipterus form a synostosis joint, representing a distinct pectoral girdle adaption during pterosaur flight evolution, different from that of birds. The residual of the articular cartilage of the glenoid fossa supports the potential for cartilage tissue preservation in this location. The morphology of the acrocoracoid process of Hamipterus indicates it may work as a pulley for M. supracoracoideus as the main power of flight upstroke resembles that of birds. But the saddle type of the shoulder joint of the pterosaur may limit the rotation of the humerus head, suggesting a particular mechanism to control the angle of attack unlike birds. The presence of both the similarity and differences between the flight apparatus of pterosaurs and birds are highlighted in our research, which may be related to the flight mechanism and forelimb functional adaption. The distinctive feature of the flight apparatus of pterosaur should be treated with caution in future research, to better understand the life of this unique extinct volant vertebrate.
PubMed: 36787121
DOI: 10.1002/ar.25167 -
Evolution; International Journal of... Oct 2015While fore- and hindlimbs are commonly assumed to be serially homologous, the serial homology of the pectoral and pelvic girdles is more ambiguous. We investigate the...
While fore- and hindlimbs are commonly assumed to be serially homologous, the serial homology of the pectoral and pelvic girdles is more ambiguous. We investigate the degree to which a common history, developmental program, and gene network are shared between the girdles relative to the rest of the appendicular skeleton. Paleontological data indicate that pectoral appendages arose millions of years before pelvic appendages. Recent embryological and genetic data suggest that the anatomical similarity between the fore- and hindlimbs arose through the sequential, derived deployment of similar developmental programs and gene networks, and is therefore not due to ancestral serial homology. Much less developmental work has however been published about the girdles. Here, we provide the first detailed review of the developmental programs and gene networks of the pectoral and pelvic girdles. Our review shows that, with respect to these programs and networks, there are fewer similarities between pelvic and pectoral girdles than there are between the limbs. The available data therefore support recent hypotheses that the anatomical similarities between the fore- and hindlimbs arose during the fin-to-limb transition through the derived co-option of similar developmental mechanisms, while the phylogenetically older pectoral and pelvic girdles have remained more distinct since their evolutionary origin.
Topics: Animal Fins; Animals; Biological Evolution; Forelimb; Fossils; Hindlimb; Phylogeny; Vertebrates
PubMed: 26374500
DOI: 10.1111/evo.12773 -
Journal of Anatomy Nov 2020Birds have lost and modified the musculature joining the pectoral girdle to the skull and hyoid, called the pectoral extrinsic appendicular and infrahyoid musculature....
Birds have lost and modified the musculature joining the pectoral girdle to the skull and hyoid, called the pectoral extrinsic appendicular and infrahyoid musculature. These muscles include the levator scapulae, sternomandibularis, sternohyoideus, episternocleidomastoideus, trapezius, and omohyoideus. As non-avian theropod dinosaurs are the closest relatives to birds, it is worth investigating what conditions they may have exhibited to learn when and how these muscles were lost or modified. Using extant phylogenetic bracketing, osteological correlates and non-osteological influences of these muscles are identified and discussed. Compsognathids and basal Maniraptoriformes were found to have been the likeliest transition points of a derived avian condition of losing or modifying these muscles. Increasing needs to control the feather tracts of the neck and shoulder, for insulation, display, or tightening/readjustment of the skin after dynamic neck movements may have been the selective force that drove some of these muscles to be modified into dermo-osseous muscles. The loss and modification of shoulder protractors created a more immobile girdle that would later be advantageous for flight in birds. The loss of the infrahyoid muscles freed the hyolarynx, trachea, and esophagus which may have aided in vocal tract filtering.
Topics: Animals; Biological Evolution; Birds; Dinosaurs; Muscle, Skeletal
PubMed: 32794182
DOI: 10.1111/joa.13256