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Developmental Dynamics : An Official... Mar 2016The muscles of the shoulder region are important for movements of the upper limbs and for stabilizing the girdle elements by connecting them to the trunk. They have a... (Review)
Review
The muscles of the shoulder region are important for movements of the upper limbs and for stabilizing the girdle elements by connecting them to the trunk. They have a triple embryonic origin. First, the branchiomeric shoulder girdle muscles (sternocleidomastoideus and trapezius muscles) develop from the occipital lateral plate mesoderm using Tbx1 over the course of this development. The second population of cells constitutes the superficial shoulder girdle muscles (pectoral and latissimus dorsi muscles), which are derived from the wing premuscle mass. This muscle group undergoes a two-step development, referred to as the "in-out" mechanism. Myogenic precursor cells first migrate anterogradely into the wing bud. Subsequently, they migrate in a retrograde manner from the wing premuscle mass to the trunk. SDF-1/CXCR4 signaling is involved in this outward migration. A third group of shoulder muscles are the rhomboidei and serratus anterior muscles, which are referred to as deep shoulder girdle muscles; they are thought to be derived from the myotomes. It is, however, not clear how myotome cells make contact to the scapula to form these two muscles. In this review, we discuss the development of the shoulder girdle muscle in relation to the different muscle groups.
Topics: Animals; Avian Proteins; Chick Embryo; Humans; Limb Buds; Mesoderm; Muscle, Skeletal; Myoblasts, Skeletal; Shoulder; Signal Transduction; Wings, Animal
PubMed: 26676088
DOI: 10.1002/dvdy.24378 -
Journal of Anatomy Mar 2020The monobasal pectoral fins of living coelacanths and lungfishes are homologous to the forelimbs of tetrapods and are thus critical to investigate the origin thereof....
The monobasal pectoral fins of living coelacanths and lungfishes are homologous to the forelimbs of tetrapods and are thus critical to investigate the origin thereof. However, it remains unclear whether the similarity in the asymmetrical endoskeletal arrangement of the pectoral fins of coelacanths reflects the evolution of the pectoral appendages in sarcopterygians. Here, we describe for the first time the development of the pectoral fin and shoulder girdle in the extant coelacanth Latimeria chalumnae, based on the tomographic acquisition of a growth series. The pectoral girdle and pectoral fin endoskeleton are formed early in development with a radially outward growth of the endoskeletal elements. The visualization of the pectoral girdle during development shows a reorientation of the girdle between the fetus and pup 1 stages, creating a contact between the scapulocoracoids and the clavicles in the ventro-medial region. Moreover, we observed a splitting of the pre- and post-axial cartilaginous plates in respectively pre-axial radials and accessory elements on one hand, and in post-axial accessory elements on the other hand. However, the mechanisms involved in the splitting of the cartilaginous plates appear different from those involved in the formation of radials in actinopterygians. Our results show a proportional reduction of the proximal pre-axial radial of the fin, rendering the external morphology of the fin more lobe-shaped, and a spatial reorganization of elements resulting from the fragmentation of the two cartilaginous plates. Latimeria development hence supports previous interpretations of the asymmetrical pectoral fin skeleton as being plesiomorphic for coelacanths and sarcopterygians.
Topics: Animal Fins; Animals; Biological Evolution; Fishes; Fossils; Skeleton
PubMed: 31713843
DOI: 10.1111/joa.13115 -
Heliyon Sep 2023This study aims to elucidate the evolution of catfish research publications over recent decades, identify emerging research clusters, examine keyword patterns, determine... (Review)
Review
This study aims to elucidate the evolution of catfish research publications over recent decades, identify emerging research clusters, examine keyword patterns, determine major contributors (including authors, organizations, and funding agencies), and analyze their collaborative networks and citation bursts on a global scale. The USA, Brazil, China, and India collectively contribute approximately 67% of the total catfish research publications, with a marked increase in prevalence since 2016. The most frequently occurring and dominant keywords are "channel catfish" and "responses," respectively. Intriguingly, our findings reveal 28 distinct article clusters, with prominent clusters including "yellow catfish," "channel catfish", "pectoral girdle," "African catfish", "Rio Sao Francisco basin," "," and "temperature mediated". Concurrently, keyword clustering generates seven main clusters: "new species", "growth performance", "heavy metal", "gonadotropin-releasing", "essential oil", and "olfactory receptor". This study further anticipates future research directions, offering fresh perspectives on the catfish literature landscape. To the best of our knowledge, this is the first article to conduct a comprehensive mapping review of catfish research publications worldwide.
PubMed: 37810135
DOI: 10.1016/j.heliyon.2023.e20081 -
Homo : Internationale Zeitschrift Fur... Apr 2023Discussions of the evolution of sexual dimorphism in torso shape and the pectoral region assume that this dimorphism exists independently of body size. We test this... (Comparative Study)
Comparative Study
Discussions of the evolution of sexual dimorphism in torso shape and the pectoral region assume that this dimorphism exists independently of body size. We test this assumption in two human populations and further examine what is needed to understand sexual dimorphism in the pectoral region. Modern human males have broad shoulders and narrow hips relative to females, lending males a more triangular torso. The wider female pelvis is commonly attributed to obstetric pressures while the broader male pectoral girdle has been argued to be an adaptation that improves hunting or intrasexual competition. While sexual dimorphism in the pelvic girdle is known to exist after adjusting for body size across human populations, most studies of sexual dimorphism in the pectoral girdle have not adjusted the data to account for sexual size dimorphism or compared different ancestral groups. The aforementioned hypotheses explaining sexual dimorphism in the clavicle and scapula as products of natural selection are predicated on the untested assumption that sex differences do not scale with body size. This study tests this assumption by comparing various measurements of the pectoral girdle, the pelvic girdle, and six pectoral-pelvic indices of black and white South Africans of known sex and height to test whether the sexes and ancestral groups will differ in these values after adjusting for differences in body size. Comparisons of ancestral groups reveal that white South Africans have larger pectoral and pelvic dimensions than black South Africans, but that blacks have larger index values than whites. Regardless of differences in ancestry and body size, males have significantly broader pectoral regions as indicated by comparisons of both individual pectoral measurements and pectoral-pelvic indices. This pattern of sexual dimorphism is reversed in the pelvic region where females have larger skeletal elements. In addition to finding both absolute and relative differences in mean values for the pectoral and pelvic skeleton, females and males and blacks and whites differ in the scaling relationship of these traits, suggesting different allometric trajectories for these bones that may be explained by their distinct evolutionary functions, their adaptations to specific environments, or by changes in lengths due to age. These results suggest that sexual dimorphism in the pectoral region is not a product of scaling and that differences in this region reflect adaptive forces acting in unique ways on each sex, consistent with the assumptions of earlier evolutionary explanations.
Topics: Female; Humans; Male; Black People; Sex Characteristics; Pelvic Bones; White People; South Africa; Bones of Upper Extremity; Race Factors; Sex Factors; Body Height; Biological Evolution
PubMed: 36628541
DOI: 10.1127/homo/2023/1486 -
Proceedings. Biological Sciences Jul 2017Positioned at the intersection of the head, body and forelimb, the pectoral girdle has the potential to function in both feeding and locomotor behaviours-although the...
Positioned at the intersection of the head, body and forelimb, the pectoral girdle has the potential to function in both feeding and locomotor behaviours-although the latter has been studied far more. In ray-finned fishes, the pectoral girdle attaches directly to the skull and is retracted during suction feeding, enabling the ventral body muscles to power rapid mouth expansion. However, in sharks, the pectoral girdle is displaced caudally and entirely separate from the skull (as in tetrapods), raising the question of whether it is mobile during suction feeding and contributing to suction expansion. We measured three-dimensional kinematics of the pectoral girdle in white-spotted bamboo sharks during suction feeding with X-ray reconstruction of moving morphology, and found the pectoral girdle consistently retracted about 11° by rotating caudoventrally about the dorsal scapular processes. This motion occurred mostly after peak gape, so it likely contributed more to accelerating captured prey through the oral cavity and pharynx, than to prey capture as in ray-finned fishes. Our results emphasize the multiple roles of the pectoral girdle in feeding and locomotion, both of which should be considered in studying the functional and evolutionary morphology of this structure.
Topics: Animal Structures; Animals; Biomechanical Phenomena; Feeding Behavior; Locomotion; Mouth; Sharks; Skull
PubMed: 28724735
DOI: 10.1098/rspb.2017.0847 -
Royal Society Open Science Nov 2018Although evolutionary transformation of the pectoral girdle and forelimb appears to have had a profound impact on mammalian locomotor and ecological diversity, both the...
Although evolutionary transformation of the pectoral girdle and forelimb appears to have had a profound impact on mammalian locomotor and ecological diversity, both the sequence of anatomical changes and the functional implications remain unclear. Monotremes can provide insight into an important stage of this evolutionary transformation, due to their phylogenetic position as the sister-group to therian mammals and their mosaic of plesiomorphic and derived features. Here we build a musculoskeletal computer model of the echidna pectoral girdle and forelimb to estimate joint ranges of motion (ROM) and muscle moment arms (MMA)-two fundamental descriptors of biomechanical function. We find that the echidna's skeletal morphology restricts scapulocoracoid mobility and glenohumeral flexion-extension compared with therians. Estimated shoulder ROMs and MMAs for muscles crossing the shoulder indicate that morphology of the echidna pectoral girdle and forelimb is optimized for humeral adduction and internal rotation, consistent with limited data. Further, more muscles act to produce humeral long-axis rotation in the echidna compared to therians, as a consequence of differences in muscle geometry. Our musculoskeletal model allows correlation of anatomy and function, and can guide hypotheses regarding function in extinct taxa and the morphological and locomotor transformation leading to therian mammals.
PubMed: 30564424
DOI: 10.1098/rsos.181400 -
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 Anatomy Sep 2021Reduced limbs and limblessness have evolved independently in many lizard clades. Scincidae exhibit a wide range of limb-reduced morphologies, but only some species have...
Reduced limbs and limblessness have evolved independently in many lizard clades. Scincidae exhibit a wide range of limb-reduced morphologies, but only some species have been used to study the embryology of limb reduction (e.g., digit reduction in Chalcides and limb reduction in Scelotes). The genus Brachymeles, a Southeast Asian clade of skinks, includes species with a range of limb morphologies, from pentadactyl to functionally and structurally limbless species. Adults of the small, snake-like species Brachymeles lukbani show no sign of external limbs in the adult except for small depressions where they might be expected to occur. Here, we show that embryos of B. lukbani in early stages of development, on the other hand, show a truncated but well-developed limb with a stylopod and a zeugopod, but no signs of an autopod. As development proceeds, the limb's small size persists even while the embryo elongates. These observations are made based on external morphology. We used florescent whole-mount immunofluorescence to visualize the morphology of skeletal elements and muscles within the embryonic limb of B. lukabni. Early stages have a humerus and separated ulna and radius cartilages; associated with these structures are dorsal and ventral muscle masses as those found in the embryos of other limbed species. While the limb remains small, the pectoral girdle grows in proportion to the rest of the body, with well-developed skeletal elements and their associated muscles. In later stages of development, we find the small limb is still present under the skin, but there are few indications of its presence, save for the morphology of the scale covering it. By use of CT scanning, we find that the adult morphology consists of a well-developed pectoral girdle, small humerus, extremely reduced ulna and radius, and well-developed limb musculature connected to the pectoral girdle. These muscles form in association with a developing limb during embryonic stages, a hint that "limbless" lizards that possess these muscles may have or have had at least transient developing limbs, as we find in B. lukbani. Overall, this newly observed pattern of ontogenetic reduction leads to an externally limbless adult in which a limb rudiment is hidden and covered under the trunk skin, a situation called cryptomelia. The results of this work add to our growing understanding of clade-specific patterns of limb reduction and the convergent evolution of limbless phenotypes through different developmental processes.
Topics: Animals; Embryonic Development; Forelimb; Hindlimb; Lizards; Phylogeny
PubMed: 33870497
DOI: 10.1111/joa.13447 -
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