Ultrasound evaluation in combination with finger extension force measurements of the forearm musculus extensor digitorum communis in healthy subjects

<p>Abstract</p> <p>Background</p> <p>The aim of this study was to evaluate the usefulness of an ultrasound-based method of examining extensor muscle architecture, especially the parameters important for force development. This paper presents the combination of two non-invasive methods for studying the extensor muscle architecture using ultrasound simultaneously with finger extension force measurements.</p> <p>Methods</p> <p>M. extensor digitorum communis (EDC) was examined in 40 healthy subjects, 20 women and 20 men, aged 35–73 years. Ultrasound measurements were made in a relaxed position of the hand as well as in full contraction. Muscle cross-sectional area (CSA), pennation angle and contraction patterns were measured with ultrasound, and muscle volume and fascicle length were also estimated. Finger extension force was measured using a newly developed finger force measurement device.</p> <p>Results</p> <p>The following muscle parameters were determined: CSA, circumference, thickness, pennation angles and changes in shape of the muscle CSA. The mean EDC volume in men was 28.3 cm³and in women 16.6 cm³. The mean CSA was 2.54 cm²for men and 1.84 cm²for women. The mean pennation angle for men was 6.5° and for women 5.5°. The mean muscle thickness for men was 1.2 cm and for women 0.76 cm. The mean fascicle length for men was 7.3 cm and for women 5.0 cm. Significant differences were found between men and women regarding EDC volume (p < 0.001), CSA (p < 0.001), pennation angle (p < 0.05), muscle thickness (p < 0.001), fascicle length (p < 0.001) and finger force (p < 0.001). Changes in the shape of muscle architecture during contraction were more pronounced in men than women (p < 0.01). The mean finger extension force for men was 96.7 N and for women 39.6 N. Muscle parameters related to the extension force differed between men and women. For men the muscle volume and muscle CSA were related to extension force, while for women muscle thickness was related to the extension force.</p> <p>Conclusion</p> <p>Ultrasound is a useful tool for studying muscle architectures in EDC. Muscle parameters of importance for force development were identified. Knowledge concerning the correlation between muscle dynamics and force is of importance for the development of new hand training programmes and rehabilitation after surgery.</p

Studies on nerve terminations in human mucosa and skin

In spite of their accessibility and important sensory function, the nervous tissue components of human oral and vaginal mucosa and skin have been subject to very few, if any, systematic investigations. Studies on the innervation of oral tissues have mainly focused on the dental pulp, the periodontium and the gingiva, probably because of specific clinical interest, thus largely neglecting the mucosa. Genital studies comprise only in a few cases the vagina and when the vagina is included, morphological descriptions of the innervation are often very meager. In cutaneous innervation, interest has been focused on certain neural end structures, e.g. Meissner corpuscles, Merkel cell-neurite complexes, hair follicles and Pacinian corpuscles. The general purpose of the present thesis was to further our understanding of the neurohistology of the human mucosa and skin. Particular emphasis was put on regional differences in innervation within and between organs. The work also includes studies on quantification methods suitable for unbiased estimates of peripheral innervation. The last part of the thesis deals with nerve-related pathosis, where the knowledge from the first parts is applied. The following specific conclusions were drawn: (1) The human oral mucosa possess intraepithelial nerve fibres, Merkel cell-neurite complexes, non-innervated Merkelcell-like cells, lamellar and glomerular nerve corpuscles, nerves in close connection to blood vessels, accessory salivary glands, salivary gland ducts and different sized nerve bundles. Salient differences exist both in number and organisation of the intraepithelial nerve endings as well as organised corpuscles; (2) The human vaginal mucosa possess intraepithelial nerve fibres, non-innervated Merkel cell-like cells, glomerular nerve corpuscles, nerves in close connection to blood vessels and smooth muscle cells and different sized nerve bundles. The distal areas of the vaginal wall have more nerve fibres compared to the more proximal parts. The anterior wall is generally more densely innervated than the posterior wall. Larger nerve coils is found in the anterior vaginal wall only and intraepithelial nerves exclusively in the introitus region. (3) The human skin possess intraepithelial nerve fibres, Merkel cell-neurite complexes, lamellar nerve corpuscles, nerves in close connection to blood vessels, eccrine and apocrine sweat glands, hair follicles and the smooth muscle cells of the arrector pili as well as different sized nerve bundles. Evidence for the existence of free nerve endings in human epidermis was obtained. (4) Ultrastructural studies confirm that the PGP9.5 positive fibres throughout the whole living epidermis are nerve fibres. (5) For both theoretical and practical purpouses, it was concluded that the nerve fibre profile and fragment estimation methods are simple, quick and reliable. The use of the nerve fibre estimation method is dubious and the nerve length estimation method should be used if differences in epithelial and section thickness and the nerve fibres shape factors cannot be controlled for. (6) The skin intraepithelial nerve fibres varying their number and distribution pattern between body areas, with most fibres in the back and chest skin and least in the extremities. (7) The appearance of recurrent oral herpes lesions at exclusive sites correspond with local neurohistology. Only regions with epithelial innervation will express the classical intraepithelial vesicles. (8) Stress urinary incontinent women have a significant decrease in their paraurethral innervation compared to continent controls. It is suggested that an impaired innervation may reduce the sensory feed-back in this area and result in a decreased stimulus to pelvic floor contraction in order to avoid urinary leakage

A six-week hand exercise programme improves strength and hand function in patients with rheumatoid arthritis

OBJECTIVE: To evaluate the effects of hand exercise in patients with rheumatoid arthritis, and to compare the results with healthy controls. METHODS: Forty women (20 patients with rheumatoid arthritis and 20 healthy controls) performed a hand exercise programme. The results were evaluated after 6 and 12 weeks with hand force measurements (with a finger extension force measurement device (EX-it) and finger flexion force measurement with Grippit). Hand function was evaluated with the Grip Ability Test (GAT) and with patient relevant questionnaires (Disability of the Arm, Shoulder, and Hand (DASH) and Short Form-36). Ultrasound measurements were performed on m. extensor digitorum communis for analysis of the muscle response to the exercise programme. RESULTS: The extension and flexion force improved in both groups after 6 weeks (p &lt; 0.01). Hand function (GAT) also improved in both groups (p &lt; 0.01). The rheumatoid arthritis group showed improvement in the results of the DASH questionnaire (p &lt; 0.05). The cross-sectional area of the extensor digitorum communis increased significantly in both groups measured with ultrasound. CONCLUSION: A significant improvement in hand force and hand function in patients with rheumatoid arthritis was seen after 6 weeks of hand training; the improvement was even more pronounced after 12 weeks. Hand exercise is thus an effective intervention for rheumatoid arthritis patients, leading to better strength and function

Biomechanics of extreme sports - a kite surfing scenario

Do extreme sports contribute to higher biomechanical stress compared to other sports? Kite surfing is one of the upcoming popular extreme sports,where very few have studied the mechanical forces that act on the body. There are several factors that contribute to mechanical stress. For preventing injuries, it is of high interest to investigate how these forces affect the body and how the equipment can be further developed to prepare the athletes for making the sport as safe as possible. This project will study injury prevalence, motion analysis and mapping of forces and pressure during kite surfing. The outcome will be a better understanding of biomechanics of kite surfing and a construction for testing and training as well as ergonomic design ideas for the equipment

Sport performance and perceived musculoskeletal stress, pain and discomfort in kitesurfing

The purpose of this study was to obtain an overview of the specific movement patterns in kitesurfing, and the participants\u27 perceptions of musculoskeletal stress, pain and discomfort. Task analysis and survey studies were used to provide an overview of the sport, and to identify problematic issues associated with the performance of the tasks. Three different methods were complimentary used for data collection: observations (n=8), a web questionnaire (n=206) and interviews (n=17). Participants were contacted through kitesurfing events and online forums. Their ages ranged from 16-62 years. The results showed that participants experienced high musculoskeletal stress for short times during a session (jumps, tricks and strong winds), and lower, static musculoskeletal stress over a longer time (crossing). High stress was most frequently perceived in abdominal muscles. Knees and feet were the sites most frequently experienced as painful, followed by the shoulders and elbows. This study provides additional information on the performance of kitesurfing and perceived musculoskeletal stress, pain and discomfort. The results can be used as input data to develop training methods and equipment for safe and comfortable performance

Neural Signal Processing : The Underestimated Contribution of Peripheral Human C-Fibers

The microneurography technique was used to analyze use-dependent frequency modulation of action potential (AP) trains in human nociceptive peripheral nerves. Fifty-one single C-afferent units (31 mechano-responsive, 20 mechano-insensitive) were recorded from cutaneous fascicles of the peroneal nerve in awake human subjects. Trains of two and four suprathreshold electrical stimuli at interstimulus intervals of 20 and 50 msec were applied to the receptive fields of single identified nociceptive units at varying repetition rates. The output frequency (interspike interval) recorded at knee level was compared with the input frequency (interstimulus interval) at different levels of accumulated neural accommodation. At low levels of use-dependent accommodation (measured as conduction velocity slowing of the first action potential in a train), intervals between spikes increased during conduction along the nerve. At increasing levels of neural accommodation, intervals decreased because of a relative supernormal period (SNP) and asymptotically approached the minimum "entrainment" interval of the nerve fiber (11 ± 1.4 msec) corresponding to a maximum instantaneous discharge frequency (up to 190 Hz). For neural coding, this pattern of frequency decrease at low activity levels and frequency increase at high levels serves as a mechanism of peripheral contrast enhancement. The entrainment interval is a good minimum estimate for the duration of the refractory period of human C-fibers. At a given degree of neural accommodation, all afferent C-units exhibit a uniform pattern of aftereffects, independent of fiber class. The receptive class of a fiber only determines its susceptibility to accommodate. Thus, the time course of aftereffects and existence or absence of an SNP is fully explained by the amount of preexisting accommodation

Abnormal Function of C-Fibers in Patients with Diabetic Neuropathy

The mechanisms underlying the development of painful and nonpainful neuropathy associated with diabetes mellitus are unclear. We have obtained microneurographic recordings from unmyelinated fibers in eight patients with diabetes mellitus, five with painful neuropathy, and three with neuropathy without pain. All eight patients had large-fiber neuropathy, and seven patients had pathological thermal thresholds in their feet, indicating the involvement of small-caliber nerve fibers. A total of 163 C-fibers were recorded at knee level from the common peroneal nerve in the patients (36–67 years old), and these were compared with 77 C-fibers from healthy controls (41–64 years old). The ratio of mechano-responsive to mechano-insensitive nociceptors was ~2:1 in the healthy controls, whereas in the patients, it was 1:2. In patients, a fairly large percentage of characterized fibers (12.5% in nonpainful and 18.9% in painful neuropathy) resembled mechano-responsive nociceptors that had lost their mechanical and heat responsiveness. Such fibers were rarely encountered in age-matched controls (3.2%). Afferent fibers with spontaneous activity or mechanical sensitization were found in both patient groups. We conclude that small-fiber neuropathy in diabetes affects receptive properties of nociceptors that leads to an impairment of mechano-responsive nociceptors. Copyright © 2006 Society for Neuroscienc

Akademiskt ansvar

Denna rapport består av åtta kapitel baserade på en seminarieserie om akademiskt ansvar, som arrangerades av Högskolan i Borås under 2015 och 2016. Seminarierna utgjorde den fjärde omgången av de så kallade Humboldtseminarierna, som högskolan arrangerat i olika omgångar sedan 2010. Vid Humboldtseminarierna har aktuella frågor kring akademins möjligheter och utmaningar belysts utifrån olika teman, inte minst kopplat till samhällets förväntningar på forskning och högre utbildning. I det perspektivet blev akademiskt ansvar ett naturligt tema för den fjärde och avslutande omgången av Humboldtseminarierna. Just kopplingen till samhällsnytta är också en röd tråd igenom rapporten. Författarna skriver utifrån skilda erfarenheter som forskare, lärare och akademiska ledare – inte minst är rektorsperspektivet väl företrätt. Ett annat återkommande ämne är kopplingen mellan akademiskt ansvar och akademisk frihet, där ansvaret inte minst bidrar till att legitimera friheten. Kollegialitet är en viktig fråga för flera av författarna, både som princip för kvalitetsstyrning och som beslutsform. Sammantaget visar de olika bidragen att akademiskt ansvar berör många frågor av stor relevans för forskare, lärare, ledare och studenter, men också för intressenter utanför akademin. Där har författarnas bidrag goda möjligheter att ge nya insikter och inspirera till fortsatta diskussioner inom många olika områden