Hallux abductovalgus (HAV) is common foot deformity that is known to predominate in women and is often assumed to be linked to the use of inappropriate footwear. The predominance of the deformity in females has been demonstrated through many surveys across different populations. The highest prevalence of the deformity reported found 44 per cent of women affect whilst the highest prevalence in men reported a prevalence of 22 per cent. Although the condition is seen less frequently in children and barefoot populations, the female foot is still affected twice as often as the male foot in such groups, weakening the theoretical association between the deformity and footwear. A review of 100 radiographs of male and female feet found an association between the functional angle of the metatarsal head and HAV deformity and found that the female metatarsal head is more rounded than the male metatarsal head. There was no difference in the degree of metatarsus adductus (MA) deformity between males and females but in females, when the MA angle was greater than normal (24') an abnormal HAV angle was always seen. A good association was seen between the proximal articular set angle and the HAV angle that was similar for males and females. A three dimensional study of 100 bone-sets was undertaken using a technique not previously applied to this field of study. The bones of the medial column (talus, navicular, medial cuneiform and 1st metatarsal) were included. Several differences between in the shape of male and female foot bones were found including the more rounded metatarsal head shape in females. When the differences were considered together it was suggested that the medial column in the female foot would be more adducted that in the male foot and the resultant adducted position of the 1st metatarsal would predispose the female foot to HAV deformity. A study of 226 children was undertaken to investigate if a relationship between hypermobility and HAV deformity existed. A new assessment tool for measuring lower limb joint hypermobility was developed initially. No association between HAV deformity and lower limb hypermobility was found in healthy children, but a significant association was identified in children diagnosed with joint hypermobility. In a study of foot pressure measurements in 61 children, significant differences in the amount of pressure placed through the hallux, the speed of loading of the 1st metatarsal head and the position of the centre of force through the foot were found between males and females. Associations with the pressure measurements and increasing joint flexibility were only seen for extreme levels of hypermobility. No association between HAV and plantar pressure was found.

This study seeks to consider the functional characteristics of a five segment lower leg and foot model during gait, using the application of elementary kinematics to measure, analyse and describe lower leg and foot motion and compare these parameters between two subject groups with plantar pathological hyperkeratosis (PPH); PPH group one having callus under metatarsal heads 2, 3 and 4, and PPH group two having callus under metatarsal heads 1 and 5. Root's elegant theory of foot function (Root et al. 1966; Root et al. 1977) has become widely accepted in podiatry. This theory suggests the orientation of the subtalar joint axis influences the amount of motion in all the cardinal body planes. Therefore, a foot which has a joint axis which is highly inclined will exhibit more transverse plane lower leg rotation than frontal plane calcaneal motion; will be a less mobile foot; and tend to present with callus under metatarsal heads 1 and 5. Conversely, a foot with a lower inclined subtalar joint axis will exhibit more frontal plane calcaneal motion than transverse plane leg rotation; will be more mobile; and tend to have callus under the 2, 3 and 4 metatarsal heads. A non-invasive in vivo kinematic method was developed to collect three dimensional coordinates of markers attached to a novel five segment model of the lower leg and foot in order to estimate the angular displacement and motion between the lower leg and foot segments. The results have shown that there are statistically significant differences in the lower leg and foot kinematics between the PPH groups (p < 0.05) during various periods within the stance phase. These differences suggest that the motions of the lower leg and foot are similar to those proposed by the podiatric theory. However the findings contradict Root's theory within the latter stages of midstance and propulsive periods of gait.

The measurement of ankle joint dorsiflexion is an important component of the clinical examination of the foot and is also an outcome measure often employed in research. Diagnosis of ankle equinus or limited ankle dorsiflexion is based solely on this measurement. Although a great majority of research papers in this field utilise normal clinical goniometers for obtaining the maximum ankle dorsiflexion angle (MADA) and important clinical decisions are based on these findings, there is overwhelming evidence that this method is highly unreliable. Thus this thesis aimed to investigate alternative methods of measuring ankle dorsiflexion and various issues that affect the MADA in order to obtain a clear picture of foot segment movement from which an Ankle Goniometer could be consequently designed and validated. Ten different techniques were identified that included various apparatuses designed specifically for measuring ankle dorsiflexion. However, during validation, their methodological quality would have benefitted from the use of an actual patient population and comparison with a reference standard, which caused papers to score poorly on methodological quality assessment. It was concluded that issues affecting this measurement and that needed to be researched further include: foot posture, the amount of moment applied and the stretching characteristics of the calf muscle tendon unit. Experiments within this study indicated that in adults, the mean maximum pronated angles were always higher than in other postures, with 8.27o difference between the pronated and supinated postures (p=0.032) and 5.78o between pronated and neutral (p=0.000). However, the reported difference between neutral and supinated (mean angle of 2.49o) is of little clinical significance. It was observed that the forefoot always travels through a greater angle than the hindfoot in all 3 foot postures, while the hindfoot to forefoot angle increases during the application of a moment, indicating that the ‘midtarsal joint locking mechanism’ cannot be applied to passive dorsiflexion of the foot. In adolescents, there are no significant differences in the mean MADA between the 3 postures, implying that this measurement technique may be performed in any of these postures. It was also concluded that there is no need to control moment applied during this measurement procedure to produce consistent results between raters and that the calf muscle tendon unit does not stretch significantly following brief repetitive passive stretching. ii An ankle goniometer that measured purely hindfoot movement by eliminating forefoot influence and that increased reliability by holding the foot in the chosen posture, was consequently designed. This was validated by synchronizing with an electrogoniometer and an optoelectronic motion capture system. Reliability testing, with the foot held in a supinated posture as opposed to the traditional Rootian method of placing the foot at subtalar joint neutral position, spanned a number of different trials, including intra-tester and inter-tester reliability studies utilising both controlled and uncontrolled conditions, in convenience samples of healthy participants and a random sample of patients. Reliability testing between 4 raters with little experience on the utilization of this device was finally conducted. It has been shown that the Ankle Goniometer is a valid and reliable device for measuring ankle joint complex dorsiflexion both in healthy adults and in a patient population.

This thesis sets out to demonstrate the significant contribution to the field of podiatric dermatology, through the use of various forms of published documentary evidence, made by the author. In addition to the published papers submitted, a content analysis of British podiatric literature over a period of 21 years has mapped the emergence and development of the specialism of podiatric dermatology within the United Kingdom. This work demonstrates a significant increase in professional interest within this area during this period. This is evidenced through increased reporting of dermatological topics within podiatry journals in terms of related news items, advertisements and editorials. This is accompanied by an increasing number of case studies, peerreviewed papers and continuing professional development articles evident within the literature. The author has presented within this thesis a suite of fifty published articles along with verifiable evidence of professional activities related to the promotion and development of podiatric dermatology. Collectively this evidence represents a significant contribution to the development and evolution of dermatology as a specialist area within podiatry in the United Kingdom over the last fifteen years.

Electrical stimulation applied to the common peroneal nerve during the swing phase of gait is an established clinical technique for the correction of dropped foot following upper motor neuron injury. The catch-like effect of skeletal muscle refers to force augmentation resulting from the inclusion of an initial high frequency burst of two or more stimuli prior to conventional low frequency electrical stimulation. There is interest in clinical utilisation of catch-like stimulation during functional applications; however the mechanism of the effect is not fully understood. The purpose of this research was to determine if the catch-like effect is a property of the muscle alone or related to spinal reflex mediated activation. In order to investigate this, direct and reflex motor effects of conventional and catch-like stimulation during dropped foot correction and other controlled conditions were assessed in unimpaired (n=12) and stroke (n=13) populations through use of electromyography. A system was developed to enable analysis of electromyography activity shortly after the application of configurable stimulation patterns. Innovative design minimised effects of stimulation artefact such that electromyography of the tibialis anterior and soleus muscles during dropped foot correction could be assessed. This system was utilised and further refined during exploratory investigations prior to structured use with study participants. Both direct and reflex motor effects of conventional stimulation were found to vary with muscle length. At typical stimulation intensities and frequencies used during dropped foot correction, direct (orthodromic) motor activation dominates voluntary or reflex mediated activation of the tibialis anterior. Enhanced contractile force when utilising catch-like stimulation with human participants, appears an effect solely inherent to muscle with no excitatory or inhibitory spinal reflex contribution. Facilitation of reflected antidromic motor activation (F-waves) with voluntary effort, observed only within the unimpaired participant group, may be an indicator of normal neuroplasticity at the spinal cord. Findings highlight the need to consider antidromic motor effects of electrical stimulation when combining its use with voluntary function during future clinical development.