Site selection for subcutaneous injection of heparin sodium

The upper and lower boundaries were 5cm above the umbilicus to 5cm below the umbilicus, and the left and right sides were 5cm inside and outside the midline of the clavicle, avoiding the periumbilicus by 1-2cm. The two injection points were 2cm apart. During the injection, the skin lesions, surgical scars, spots or moles were avoided.