Structural Anatomy
Permanent URI for this collectionhttps://hdl.handle.net/20.500.12503/32563
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Browsing Structural Anatomy by Author "Gonzales, Lauren"
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Item Identification of ecological, locomotor, and morphological indicators of semi-terrestriality in anthropoid primates.(2024-03-21) Thompson, Indya; Perchalski, Bernadette; Maddux, Scott; Gonzales, LaurenSemi-terrestriality , the utilization of both arboreal and terrestrial environments, is commonly discussed in the primatological literature but inconsistently defined, limiting its study in fossil taxa. This project aims to fill that gap by investigating the ecological, morphological and locomotor variables that characterize semi-terrestrial taxa. 18 semi-terrestrial and 17 arboreal anthropoid taxa were identified from the literature. Ecological data were collected from mammalian demographic and environmental databases; postcranial measurements and behavioral data were collected from the literature. Three stepwise canonical variate analyses (CVA) were run (ecological, locomotor, and morphological) to identify factors that discriminate between semi-terrestrial and arboreal primates. The ecological CVA retained population size, social group size, and percentage of leaves in the diet as variables. CV1 (55.8%) differentiated semi-terrestrial platyrrhines from arboreal and semi-terrestrial catarrhines. CV2 (26.9%) distinguished semi-terrestrial platyrrhines and catarrhines cluster away from their arboreal counterparts. The behavioral CVA retained bridging, leaping, quadrupedal walking, climbing, scrambling/clambering and bimanual suspension as variables. CV1 (62.3%) separated semi-terrestrial platyrrhines from semi-terrestrial catarrhines, while CV2 (31.5%) distinguished both semi-terrestrial taxa from arboreal taxa. The morphological CVA did not retain any size-corrected variables, with no iteration of relative long bone lengths differentiating between any of the groups. These results indicate select ecological and locomotor variables can reliably identify semi-terrestrial taxa, helping to improve our understanding of this enigmatic behavior. Future studies should likely include measures of specific bony features to more fully investigate potential morphological indicators of semi-terrestrial behaviors.Item Masticatory muscle morphology in early postnatal mice with osteogenesis imperfecta(2024-03-21) Ansari, Zahra; Miller, Courtney; Emmanuel, Tanusha; Handler, Emma; Gonzales, Lauren; Organ, Jason; Menegaz, Rachel A.Purpose: Osteogenesis imperfecta (OI) is a connective tissue disorder resulting from mutations in COL1A1 or COL1A2, responsible for encoding type I collagen alpha chains. While OI is primarily distinguished by manifestations of bone fragility, including recurrent fractures and bone deformities, muscle abnormalities have also been documented in those affected by OI. While prior research has shown postcranial muscle weakness in mouse models of OI, it remains unclear whether this also applies to feeding musculature and if these differences are present at birth or develop postnatally. This study investigates the development of the masticatory muscles during the early postnatal period in a mouse model. Our hypothesis posits that mice affected by OI will exhibit decreased muscle mass, and therefore potentially weaker muscles, in comparison to unaffected mice. Methods: Cranial tissues from OIM mice (B6C3Fe a/a-Col1a2oim/J) and unaffected wild type (WT) littermates were collected at day of birth (P0) and postnatal day 14 (P14). Tissues were fixed and stained with 1.25% buffered Lugol’s solution, then micro-CT scanned with a reconstruction of 0.02 mm3 voxels. 3D Slicer software was used to isolate and measure the volumes of the superficial masseter, deep masseter, and temporalis muscles. Muscle volumes were compared between genotypes using a Mann-Whitney U test. Results: At birth, no significant differences were observed in body mass or muscle volumes between OIM and WT mice. A trend was observed for OIM mice to have lower superficial masseter volumes compared to WT mice at P0, but this difference was not significant. At P14, OIM mice have significantly lower body weights (p=0.002). Data collection is ongoing for volumetric muscle data from the P14 stage. After birth, body masses diverge rapidly between OIM and WT mice. These growth curves suggest poor feeding performance during the suckling stage in OIM mice. Although masticatory muscle volumes (similar to body mass) start out similar between genotypes at birth, a trend for decreased superficial masseter volume in OIM mice suggests feeding musculature will also lag behind unaffected mice during early postnatal growth. Conclusion: The production of strain above an osteogenic threshold by feeding musculature is critical to typical craniofacial growth during early life. Weaker masticatory muscles may produce lower (yet still osteogenic) levels of strain, contributing to the midfacial hypoplasia seen in OIM mice. A better understanding of muscle development during this critical growth period will provide insight on feeding disorders seen in OI, and the development of the craniofacial phenotype in pediatric patients with OI.Item Pre-weaning craniofacial development in mice with Osteogenesis Imperfecta(2024-03-21) Miller, Courtney; Emmanuel, Tanusha; Gonzales, Lauren; Handler, Emma; Organ, Jason; Menegaz, Rachel A.The craniofacial region plays a pivotal role in various physiological functions, including mastication, speech, and respiration. Early life behaviors have a profound role in shaping adult structure and function. In the early stages of life, all mammals undergo the transition from suckling to mastication, a period coinciding with rapid cranial biomineralization. Osteogenesis imperfecta (OI), a genetic disorder that impacts the production of type I collagen, disrupts biomineralization, leading to craniofacial growth differences affecting overall quality of life. This study investigates the preweaning craniofacial growth trajectory in mice OI (the OIM mouse) compared to unaffected wild type (WT mice). We hypothesize that mice with OI will exhibit smaller overall size and greater craniofacial variation than WT mice due to the abnormal collagen synthesis during skull development. Micro-CT based geometric morphometric analyses of the OIM mouse model (B6C3Fe a/a-Col1a2oim/J) were used to compare craniofacial size and shape differences at birth (P0; n=27 OIM / 20 WT) and postnatal days 7 (P7; n=21/21) and 14 (P14; n=16/20). The SlicerMorph package for 3D Slicer software was used to generate landmark point clouds for the cranium and mandible. Dimension ratios were calculated as width/length for the crania. Principal component analysis with Procrustes ANOVA were used to examine differences between genotypes at each time point, and a canonical variate analysis (CVA) used to identify shape features that maximize the distinction between genotypes across all time points. Results reveal the development of significant differences in both shape and size between the genotypes following birth. At birth, size and shape are similar between genotypes. However, by P7 and P14, OIM mice are significantly (p<0.05) smaller and display pronounced shape changes (p<0.001) characterized by larger neurocranium and shorter viscerocranium. Additionally, OIM mice have significant mandibular alterations by P7 (p<0.001) - shorter ramus, more posterior position of the coronoid, and shorter and wider dental arcade. All of these changes align with the suckling developmental stage, suggesting changes in the ratio of growth between the neurocranium and the viscerocranium during early life. Widening the neurocranium while shortening the viscerocranium during this critical developmental stage alters the masticatory muscle line of action, consequently, influences the health of individuals with OI. These findings underscore the suckling stage’s significance in shaping the foundational structures for later life, providing insights into OI craniofacial development, and suggest potential benefits to directing interventions toward an earlier time point for more effective treatment of OI.