镁是细胞内的一种主要阳离子,其含量仅次于钾。镁在细胞内不仅以游离形式存在,也与生物膜及某些酶相结合。镁在人体内主要分布于细胞内,其细胞外含量不及总量的百分之一。由于当细胞内的镁减少时,血清镁仍可能在正常范围内,故血清镁含量的变化不能直接反映细胞内镁的变化。但是,当血清镁的浓度低于其正常值(<1·2meq/L)时,则表明必 Magnesium is a major intracellular cation, its content is second only to potassium. Magnesium in the cell not only in free form, but also with the biofilm and some enzymes. Magnesium in the human body is mainly distributed in the cells, the extracellular content of less than one percent of the total. Because when the reduction of intracellular magnesium, serum magnesium may still be within the normal range, so changes in serum magnesium can not directly reflect changes in intracellular magnesium. However, when the concentration of serum magnesium is below its normal value (<1 · 2 meq / L)