In my current role as a lecturer in human anatomy at the University of Liverpool I am establishing a new lab and research projects in the area of functional morphology and biomechanics. If you are interested in a PhD in this field, please contact me. Some of my other current and previous work is highlighted below.
Evolution of unique cranial morphology and function in lagomorphs
This is a funded NERC Doctoral Training Program of which I am the primary supervisor for Amber Wood-Bailey. Rabbits and hares (leporids, lagomorphs) are unique among mammals for having a joint within the cranium that provides movement, rather than having a completely rigid skull. This movement, or cranial kinesis, is common in vertebrates such as reptiles, but has not evolved in any other mammals, so its evolution and function is not well understood. Early studies have suggested that cranial kinesis in rabbits functions as a shock-absorbing mechanism to dissipate kinetic energy during impacts associated with fast running. However, this has not been tested. In this project, Amber will take an evolutionary comparative approach to explore how the biomechanics, ecology, and environmental factors influence the evolution of lagomorph skull shape and function, through the application of sophisticated computational methods such as finite element analysis, biplanar x-ray videography and geometric morphometrics.
The biomechanics of craniosynostosis
This project aims to advance knowledge of the biomechanical role of sutures (soft connective tissue joints between the skull bones) in overall skull function by investigating how the patterns of cranial strain are influenced by the patency of sutures. Conditions such as craniosynostosis (~1 in every 2000 live births) involves the premature closure of sutures, and unless there is early surgical intervention this can lead to serious clinical pathologies, such as head malformations and brain damage.
The role of soft tissues in cranial biomechanics
This BBSRC funded project (2015-1018) with UCL and the University of Hull used a combination of traditional anatomical work and computational biomechanics (MDA and FEA) to understand the mechanical role and significance of non-muscular soft tissues in the reptilian and mammalian skull during feeding.
Figure: lateral view of a rabbit skull
Figure: lateral view of a rabbit skull
Human foot anatomy and function
I also occationally study the functional anatomy of the human intrinsic foot muscles. The human foot is unique among vertebrates and is characterized by a pronounced longitudinal arch (LA) that compresses and recoils in response to external load during locomotion. This has typically been considered a passive process; however, it has recently been shown that the plantar intrinsic foot muscles have the capacity to actively assist in supporting the LA. Through dissection and imaging I investigate anatomical variation of the intrinsic foot muscles.
3D Visualisation and Reconstruction
Using a combination of CT and MRI scanning, gross dissection and biomechanical modelling, we can visualize and investigate the function of a variety of soft- and hard-tissue structures.
Figure: Digital dissection of the temporalis muscle group in the common wombat. 3D PDF available |
Information gathered from extant animals can then be compared to fossil specimens, allowing the reconstruction of muscles and other soft-tissue structures, which are rarely preserved in fossils.
Figure: Digital reconstruction of the jaw adductor musculature in the Diprotodon |
Cranial Morphology, Biomechanics and Diet of Marsupial Herbivores
Marsupial herbivores come in many shapes and sizes, from hopping kangaroos to lumbering wombats. Studies on teeth, dentaries and jaw adductor muscles indicate that marsupial herbivores exhibit different specializations for grazing and browsing, including hypsodonty, molar progression and high bite forces. However, the relationships between skull morphology, biomechanical performance and diet are still relatively unknown. This research aims to investigate the interaction between biomechanical and non-biomechanical factors, including the lifestyle of the animal and its environment, in selection for skull morphology to meet multiple functional demands. In accordance with previous studies, results show the mammalian skull may not be optimized solely to resist forces generated during feeding.
Figure: Predicted distribution of stress across the cranial models of the (A) common wombat (V. ursinus), (B) koala (P. cinereus), (C) red kangaroo (M. rufus), and (D) swamp wallaby (W. bicolor).
Figure: Predicted distribution of stress across the cranial models of the (A) common wombat (V. ursinus), (B) koala (P. cinereus), (C) red kangaroo (M. rufus), and (D) swamp wallaby (W. bicolor).
Sinus Morphology of Marsupial Megafauna
Cranial sinuses are air-filled cavities resulting from the resorption and deposition of bone through pneumatisation in response to biomechanical stress. The morphology of a pneumatic bone represents an optimisation between strength and being light weight. Marsupial megafauna are "airheads" in that most of their skull is composed of very large air sinuses, and their brains are relatively small compared to the overall size of the skull. The size and morphology of the sinuses changes with the size of the animal and the morphology of the skull. Using CT scans to reconstruct the skulls and estimate the volume of the sinuses and brains we can get a better understanding of their size, morphology and evolution.
Figure: Three-dimensional reconstructions of Diprotodon optatum (A-B), Zygomaturus tasmanicum (C-D), Neohelos stirtoni (E-F) and Propalorchestes sp. (G-H) showing the extent of the auditory, squamosal, parietal and frontal sinuses in blue, and brain endocast in red. Skulls are shown in dorsal (A, C, E, G) and lateral (B, D, F, H) views. Scale bars represent 10 cm.
Figure: Three-dimensional reconstructions of Diprotodon optatum (A-B), Zygomaturus tasmanicum (C-D), Neohelos stirtoni (E-F) and Propalorchestes sp. (G-H) showing the extent of the auditory, squamosal, parietal and frontal sinuses in blue, and brain endocast in red. Skulls are shown in dorsal (A, C, E, G) and lateral (B, D, F, H) views. Scale bars represent 10 cm.
Cranial Morphology and Function of Diprotodon
This project is work from my PhD. Diprotodon optatum is the largest marsupial known and became extinct about 45,000 years ago. Using CT scanning and an engineering technique called finite element analysis (FEA) I am investigating the structure and function of the extensive cranial sinuses. Another aspect of this project is predicting the bite force and feeding biomechanics to explore the diet and behaviour of these animals.
