Over 30 tetrapod groups have evolved a snake-like, elongate, limbless body plan. Studies of the patterns of limb reduction have revealed a close relationship between the reduction of the limbs and body elongation; however, the loss of the skeletal elements that support the limb, the pectoral girdle, has been less thoroughly examined. Here, I use computed tomography to generate three dimensional models of the pectoral girdles of an Australian skink genus, Lerista. This group contains pentadactyl species, fully limbless species and many species with intermediate morphologies. I employed a 3D geometric morphometric analysis to compare the shapes of these structures and revealed that the reduction of the pectoral girdle is correlated with the degree of loss in the limbs. The girdle in species with well developed limbs is longer and more narrow than the short, broad girdle of species with highly reduced or absent limbs, but the degree of reduction is only loosely correlated with the degree of reduction in the limbs. Certain events appear to occur concurrently such as the losses of the coracoid foramen and the humerus, but other events such as the loss of the epicoracoid are not consistently associated with any other event. The extent to which limb reduction is associated with the degree of pectoral girdle reduction and the morphology of the girdles appears to be closely associated with subclade, with individuals from closely related clades showing dramatically different degrees of girdle reduction despite similarities in the degree of limb loss. Despite these differences, the patterns in Lerista are generally more similar to each other than to those of other lizard groups, and more similar to those of other skinks than to those of other groups of lizards. Though some aspects of limb loss are common to all lizard groups that have evolved a serpentine body plan, this study shows that, even in closely related groups, this transition does not proceed in exactly the same way. / Master of Science / Over 30 tetrapod groups have evolved a snake-like, elongate, limbless body plan. Many studies of the patterns of limb reduction (evolutionarily losing fingers and toes) have revealed a close relationship between the reduction of the limbs and body elongation; however, the loss of parts of the internal skeleton that support the limb (e.g. shoulder blade, collar bone) have been less thoroughly examined. Here computed tomography was used to generate three dimensional models of the pectoral girdle, the array of limb support bones, of the Australian lizard genus Lerista. This group contains species that have five fingers, species which are fully limbless (and thus have no fingers), and some that have intermediate numbers of fingers. I quantitatively compared the pectoral girdle shapes, which revealed that the reduction of the pectoral girdle occurs gradually and in a series of steps that are loosely associated with how many fingers are present. The pectoral girdle as a whole shows a more obvious reduction in length than in width, with this length reduction being loosely associated with the number of fingers present. Certain events appear to occur concurrently such as the loss of a small hole in one of the bones through which nerves that control the arm pass and loss of the upper arm bone. However other events, such as the loss of a cartilaginous structure called the epicoracoid is not consistently associated with any other event. The extent to which limb reduction is associated with the extent of pectoral girdle reduction is group dependent, with individuals from closely related groups showing dramatically different degrees of pectoral girdle reduction despite a similarity in the degree of digit loss. Despite these differences, the patterns in Lerista are more similar to each other than to those of other lizard groups, and more similar to those of other skinks than to those of other groups of lizards. Though some aspects of limb loss are common to all lizard groups that have evolved a snake-like body plan, this study reveals that even in closely related groups, this transition does not proceed in exactly the same way.

Scincidae (skinks) comprise one of the largest families of lizards, and the more than 1300 species show great variation in body size and form, and are found worldwide in a diversity of habitats. The group presents many interesting questions ranging from the colonization of oceanic islands, to the evolution of limb loss, yet most of these and other questions remain understudied. The purpose of this dissertation is to use multiple mitochonidrial and nuclear DNA markers in connection with current cladistic methods to address evolutionary questions at many levels within Scincidae. In chapter one, a molecular phylogenetic study, based on six genes and extensive analyses support Cordylidae+Xantusiidae as its sister group, and confirm the paraphyly of Scincinae. The Acontinae is the sister group to all remaining skinks, while Feylininae is nested within an otherwise monophyletic southern African scincine clade. Limited support for reversal of limb and digit loss is found. In chapter two, the monophyly and relationships of Malagasy scincines are investigated using data from seven gene regions. Malagasy scincines are monophyletic, and derived from a single colonization from southern Africa. Our analyses confirm the paraphyly of Amphiglossus, and support Madascincus as a valid genus. Madascincus is sister to a monophyletic Paracontias, while Voeltzkowia is basal to the remaining Amphiglossus and Pygomeles. Chapter three uses seven gene regions to infer relationships within South American Mabuya, and to test the hypothesis of two independent colonizations from Africa to the New World. Direct Optimization (DO) is compared with traditional alignment methods, and multilocus maximum likelihood and Bayesian methods are used to date divergence times within the group. Results show that DO consistently finds more optimal tree topologies regardless of the optimality criterion used, and provides the ability to use models throughout the alignment and tree reconstruction process. South American Mabuya are not monophyletic, and the two colonization hypothesis is confirmed with parametric bootstrapping. Within the mainland species of Mabuya, many taxonomic problems are uncovered including multiple species complexes. Due to the lack of reliable fossil information, dating methods differ greatly in their estimates of divergence dates within Mabuya.

The psychometric properties of a new high-level mobility outcome measure for Service Members (SMs) with traumatic lower limb loss called the Comprehensive High-level Activity Mobility Predictor (CHAMP) was developed in order objectively evaluate functional abilities and measure change in function throughout the rehabilitation process. The CHAMP was administered to a population of SMs with traumatic lower limb loss who were representative of those who have suffered limb loss in recent conflicts. In addition, a population of non-amputee Active Duty soldiers completed the CHAMP and provided normative data for high-level mobility and threshold levels of performance for those SMs with lower limb loss. A simple grading system, absent of floor and ceiling effects, generates a composite score providing a single numeric value representing the physical performance factors of high-level mobility in different plane of motion and under different conditions. The CHAMP was found to be a safe, reliable, valid, and responsive performance-based outcome measure of high-level mobility. It was found to have excellent interrater and test-retest reliability suggesting that it is a stable and repeatable measure of high-level mobility. Convergent construct validity and known group methods were utilized to establish the CHAMP as a valid measure of high-level mobility. Predictive models of CHAMP performance were established utilizing variables representing impairments of body structure and function and contextual factors by level of lower limb amputation. The CHAMP has the potential to be used for lower limb amputees throughout the rehabilitation process and could translate to the non-amputee population for assessment of high-level mobility capabilities.

Everyday ecologically relevant tasks that affect organismal fitness, such as foraging, reproduction, predator avoidance, and escape responses, rely upon successful locomotion. The effectiveness of animal locomotion depends on many underlying factors, such as the morphology of the locomotor limbs, which evolved to fulfill specific locomotor tasks. Besides morphology, the material properties of the limbs also play a crucial role in locomotion. The skeletal structures of locomotor limbs must be able to withstand the repeated stresses that come with locomotion, either on land or underwater, as they use their limbs to generate propulsive forces. The natural environment animals move in is complex and dynamic, as various conditions crucial to locomotor performance can change unexpectedly. Perturbations to locomotor stability can take different forms, such as elevation changes, obstacles, substrate changes, and slipping. To maintain stable locomotor performance in these environments, animals rely on locomotor control mechanisms to counteract destabilizing effects of locomotor perturbations. In this Dissertation, I investigated the biomechanical control mechanisms and morphological adaptations during locomotion in challenging locomotor scenarios. Over the course of three chapters, the goals were to: 1) explore the effects of limb loss on a side-ways running sprint specialist, the Atlantic ghost crab, 2) determine the response and control mechanisms that allow ghost crabs overcome slip perturbations, and 3) to describe the pelvic morphology of bottom-walking Antarctic plunderfish and compare the pelvic morphologies among multiple species of nothenioids that do not bottom-walk. This study demonstrates the robustness of Atlantic ghost crabs to limb loss and slip perturbations. Paired limb removals resulted in a pattern of kinematic adjustments, which reduced locomotor performance by up to 25%, which was dependent on specific limbs being lost. I suggest that these limbs serve more important limb functions that can’t be replaced by the remaining limbs, however the loss of these particular limbs also results in re-patterning of limb relationships, which may reveal a neural component that may be the cause of decreased locomotor performance. Slip perturbations on the other hand were found to not have any significant effects on the locomotor performance of ghost crabs. Kinematics remained constant as ghost crabs traversed the slip surface, suggesting that ghost crabs may rely on feedforward control to overcome slip perturbations, however further studies measuring neural activity are required to confirm our finding. Most importantly though this chapter demonstrates and corroborates the role of momentum and how it allows animals to overcome perturbations. The last chapter investigated the pelvic morphology and material properties of fin rays in bottom walking fish. The Antarctic plunderfish was found to possess high flexural stiffness in its pelvic fin rays, which likely facilitate the bottom walking behavior in this species. Other, non-bottom walking notothenioids did not have fin rays of similar stiffness. Pelvic plate morphology was not different between species, however there were stark differences in mineralization. The bottom-walking fish had higher bone mineral density compared to the other species analyzed in this chapter. I also found mineralization patterns which seem to align with muscle fiber alignment of the major pelvic muscles, suggesting that these regionalized increases in stiffness provide stability while allowing for a lightweight pelvic plate. / Biology

Bakgrund: Att förlora ett ben innebär en påfrestning på livet och livskvalitén sänks. Amputation betyder att skadad vävnad och skelett avlägsnas och det kan bero på trauma, cirkulatorisk svikt eller infektioner. Syfte: Var att beskriva upplevelsen av att ha förlorat en nedre extremitet genom amputation. Metod: Allmän litteraturöversikt användes för att sammanställa och skapa en översikt över befintlig forskning. Analysmodellen var induktiv utifrån Fribergs trestegsmodell. Resultat: Fem huvudkategorier med tillhörande underkategorier sammanställdes. De fem huvudkategorierna var; upplevelser av hur livet förändrats och hur andra ser på en själv, upplevelsen av information och stöd från sjukvården, hjälpmedel som hinder eller möjlighet till självständighet, att behöva socialt stöd på vägen mot ett nytt liv och positivt tänkande – en nyckelfaktor. Diskussion: Litteraturstudien visade att behovet av information var av stor vikt under hela amputationsprocessen, de amputerade upplevde att det var lite information som gavs ut och det skulle vara relevant att ge ut information både muntligt och skriftligt. Litteraturstudien visade också att protesen spelade en stor roll för synen på framtiden. Många såg den som nyckeln tillbaka till det tidigare livet och till ökad självständighet. Vidare föreslås mer forskning med kvalitativt tillvägagångssätt avseende de psykiska aspekterna hos såväl de amputerade som deras anhöriga.

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Prosthesis treatment requires the close interaction of different actors. In fitting prostheses to patients, special attention is given to the manufacturing of the socket. The continuous development of the technologies involved in the fitting and optimization of prostheses is shown in the literature. The assessment of orthopedic technicians and their influence in the process is thus far largely unexplored. Ten orthopedic technicians were interviewed about the socket fitting process after transfemoral amputation. The research goal was to clarify the socket treatment process with regards to the German context. The results showed that the orthopedic technicians focussing on the patient during the fitting process. This study underlines the importance of interaction and empathy. Volume fluctuations are decisive within the treatment process and are interactively influenced by various factors. Furthermore, the research emphasizes the need for appropriate assistive technologies and the potential for the further development of existing systems.

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No description available.