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Anatomical Record (Hoboken, N.J. : 2007) Mar 2021The ontogeny of the paired appendages has been extensively studied in lungfishes and tetrapods, but remains poorly known in coelacanths. Recent work has shed light on...
The ontogeny of the paired appendages has been extensively studied in lungfishes and tetrapods, but remains poorly known in coelacanths. Recent work has shed light on the anatomy and development of the pectoral fin in Latimeria chalumnae. Yet, information on the development of the pelvic fin and girdle is still lacking. Here, we described the development of the pelvic fin and girdle in Latimeria chalumnae based on 3D reconstructions generated from conventional and X-ray synchrotron microtomography, as well as MRI acquisitions. As in other jawed vertebrates, the development of the pelvic fin occurs later than that of the pectoral fin in Latimeria. Many elements of the endoskeleton are not yet formed at the earliest stage sampled. The four mesomeres are already formed in the fetus, but only the most proximal radial elements (preaxial radial 0-1) are formed and individualized at this stage. We suggest that all the preaxial radial elements in the pelvic and pectoral fin of Latimeria are formed through the fragmentation of the mesomeres. We document the progressive ossification of the pelvic girdle, and the presence of a trabecular system in the adult. This trabecular system likely reinforces the cartilaginous girdle to resist the muscle forces exerted during locomotion. Finally, the presence of a preaxial element in contact with the pelvic girdle from the earliest stage of development onward questions the mono-basal condition of the pelvic fin in Latimeria. However, the particular shape of the mesomeres may explain the presence of this element in contact with the girdle.
Topics: Animal Fins; Animals; Biological Evolution; Fishes; Fossils; Magnetic Resonance Imaging; Pelvis; Phylogeny
PubMed: 32445538
DOI: 10.1002/ar.24452 -
BMC Veterinary Research Aug 2023Morphometric study of the bony elements of the appendicular skeleton in the ostrich was fully described and identified. The appendicular skeleton included the bones of...
BACKGROUND
Morphometric study of the bony elements of the appendicular skeleton in the ostrich was fully described and identified. The appendicular skeleton included the bones of the pectoral girdle, the wing, the pelvic girdle and the pelvic limb.
RESULTS
The shoulder girdle of the ostrich included the scapula and coracoid bones. The scapula appeared as a flattened spoon-like structure. The coracoid bone appeared quadrilateral in outline. The mean length of the scapula and coracoid (sternal wing) were 15.00 ± 0.23 and 10.00 ± 0.17 cm, respectively. The wing included the humerus, ulna, radius, radial carpal bone, ulnar carpal bone, carpometacarpus and phalanges of three digits. The mean length of the humerus, radius, and ulna were 33.00 ± 0.46, 10.50 ± 0.40 and 11.50 ± 0.29 cm respectively. The carpometacarpus was formed by the fusion of the distal row of carpal bones and three metacarpal bones. Digits of the wing were three in number; the alular, major and minor digits. Os coxae comprised the ilium, ischium and pubis. Their mean lengths were 36.00 ± 0.82 cm, 32.00 ± 0.20 and 55.00 ± 0.2.9 cm, respectively. The femur was a stout short bone, that appeared shorter than the tibiotarsus. The mean length of the femur, tibiotarsus, and tarsometatarsus were 30.00 ± 0.23, 52.00 ± 0.50 and 46.00 ± 0.28 cm. Tibiotarsus was the longest bone in the pelvic limb. The fibula was a long bone (44.00 ± 0.41 cm) lying along the lateral surface of the tibiotarsus. The tarsometatarsus was a strong long bone formed by the fusion of the metatarsal (II, III, IV) and the distal row of tarsal bones. It was worth mentioning that metatarsal II was externally absent in adults.
CONCLUSIONS
In the appendicular skeleton of ostrich, there were special characteristic features that were detected in our study; the clavicle was absent, the coracoid bone was composed of a sternal wing and scapular wing, the ulna was slightly longer in length than the radius. The coupled patellae i.e., the proximal and distal patella were observed; and the ostrich pedal digits were only two; viz., the third (III) and fourth (IV) digits.
Topics: Animals; Struthioniformes; Scapula; Metatarsal Bones; Femur; Humerus
PubMed: 37542302
DOI: 10.1186/s12917-023-03665-6 -
Journal of Morphology Aug 2022The Greater Rhea (Rhea americana, Rheidae) is a flightless paleognath with a wide geographical distribution in South America. The morphology of its shoulder girdle and...
The Greater Rhea (Rhea americana, Rheidae) is a flightless paleognath with a wide geographical distribution in South America. The morphology of its shoulder girdle and wings are different from those of flying birds and some characteristics are similar to basal birds and paravian theropods. We present a detailed osteological, myological, and functional study of the shoulder and the wing of the Greater Rhea. Particular features of the anatomy of the pectoral girdle and wing of Rhea include the lack of triosseal canal, reduced origin area of the mm. pectoralis p. thoracica and supracoracoideus and the lack of a propatagium. The wing muscle mass is markedly reduced, reaching only 0.89% of total body mass (BM). Forelimb muscles mass values are low compared to those of flying birds and are congruent with the non-use of wings for active locomotion movements. R. americana does not flap the wings dorso-ventral as typical for flying birds, but predominantly in cranio-caudal direction, following a craniolateral to caudomedial abduction-adduction arc. When the wings are fully abducted, they are inverted L-shaped, with the inner surface caudally faced, and when the wings are folded against the body, they do not perform the complete automatic wing folding nor the circumduction of the manus, a movement performed by extant volant birds. This study complements our knowledge of the axial musculature of the flightless paleognaths and highlights the use of the Greater Rhea as a model, which may help understand the evolution of Palaeognathae, as well as the origin of flapping flight among paravian theropods.
Topics: Animals; Flight, Animal; Osteology; Rheiformes; Struthioniformes; Wings, Animal
PubMed: 35673834
DOI: 10.1002/jmor.21486 -
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 -
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