Muscle fascicles lengthen in response to chronic passive stretch through in-series sarcomere addition in order to maintain an optimum sarcomere length. In turn, the muscles’ force generating capacity, maximum excursion, and contraction velocity is enhanced. Thus, longer fascicles suggest a greater capacity to develop joint power and work. However, static fascicle length measurements may not be taking sarcomere length differences into account. Thus, we considered relative fascicle excursions through passive ankle dorsiflexion may better correlate with the capacity to generate joint power and work than fascicle length. Therefore, the aim of the present study was to determine if medial gastrocnemius relative fascicle excursions correlate with ankle joint power and work generation during gait in typically developing children. A sample of typically developing children (n = 10) were recruited for this study and data analysis was carried out on 20 legs. Medial gastrocnemius relative fascicle excursion from resting joint angle to maximum dorsiflexion was estimated from trigonometric relations of medial gastrocnemius pennation angle and thickness obtained from B-mode real-time ultrasonography. Furthermore, a three-dimensional motion capture system was used to obtain ankle joint work and power during the stance phase of gait. Significant correlations were found between relative fascicle excursion and peak power absorption (–) r(14) = −0.61, P = .012 accounting for 31% variability, positive work r(18) = 0.56, P = .021 accounting for 31% variability, and late stance positive work r(15) = 0.51, P = .037 accounting for 26% variability. The large unexplained variance may be attributed to mechanics of neighboring structures (e.g., soleus or Achilles tendon mechanics) and proximal joint kinetics which may also contribute to ankle joint power and work performance, and were not taken into account. Further studies are encouraged to provide greater insight on the relationship between relative fascicle excursions and joint function.
INTRODUCCIÓN: Los quistes esplénicos aislados son raros en niños y potencialmente graves y casi siempre difíciles de diagnosticar. CASO CLÍNICO: Paciente de 5 años, traído a urgencias por fiebre alta, dolor abdominal y vómito. Reporte hematológico: leucocitosis con elevación de reactantes de fase aguda, hemocultivo negativo y coprocultivo positivo para Salmonella serogrupo D. En la radiografía de tórax se objetivó infiltrado basal izquierdo y derrame pleural; en la ecografía abdominal se detectó lesión quística intraesplénica de gran tamaño. Con el diagnóstico de absceso gigante del bazo se pautó tratamiento antibiótico intravenoso y drenajes percutáneos repetidos hasta la intervención quirúrgica definitiva con extirpación quística parcial y fenestración de la cápsula. En el cultivo del absceso creció una Salmonella del mismo serogrupo. El análisis anatomopatológico de la pieza fue compatible con quiste epitelial primario. CONCLUSIONES: Como parte del diagnóstico diferencial de cualquier paciente con signos sugerentes de afectación en el hipocondrio izquierdo deben considerarse los quistes esplénicos. En los últimos años ha habido grandes avances en su tratamiento; en pacientes pediátricos suele ser conservador. PALABRAS CLAVE: Quiste epitelial; absceso esplénico; esplenectomía; niños
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