An orthosis chosen from an elastic venous retention orthosis and an elastic venous compression orthosis is intended to treat a venous disorder of a lower limb of a patient in a service position in which it is fitted on the lower limb. The orthosis has a leg part, a ribbed top configured to maintain the orthosis in the service position, and a tab fixed on the ribbed top in such a way as to be accessible to the patient in the service position.
