An orthosis chosen from a venous support orthosis and an elastic venous compression orthosis, the orthosis including a ribbed top and a leg part, the ribbed top including an intermediate part extending the leg part, the stitch being different on each side of the boundary separating the leg part and the intermediate part, a welt extending the intermediate part and of a height less than 1.5 cm.

A circular knitting machine for knitwear, comprising a needle-holding cylinder, having longitudinal grooves housing a plurality of needles, and a needle-holding ring, having radial grooves housing a plurality of holding-down sinkers, and wherein each needles is paired with an adjacent sinker to form a needle-sinker assembly; the knitting machine comprises, for each needle-sinker assembly, a pre-selection element paired with the respective needle and comprising a connecting portion selectively cooperating with the sinker belonging to the same needle-sinker assembly; each radial groove has a rear section and a front section; the front section is wider than the rear section and configured for laterally containing and guiding the connecting portion of the pre-selection element.

A circular knitting machine for knitwear, comprising a needle-holding cylinder, having longitudinal grooves housing a plurality of needles, and a needle-holding ring, having radial grooves housing a plurality of holding-down sinkers, and wherein each needles is paired with an adjacent sinker to form a needle-sinker assembly; the knitting machine comprises, for each needle-sinker assembly, a pre-selection element paired with the respective needle and comprising a connecting portion selectively cooperating with the sinker belonging to the same needle-sinker assembly; each radial groove has a rear section and a front section; the front section is wider than the rear section and configured for laterally containing and guiding the connecting portion of the pre-selection element.