The orbital veins.
D001164:Arteriovenous Fistula / Q000000981:diagnostic imaging; D006391:Hemangioma / Q000000981:diagnostic imaging; D006801:Humans; D009915:Orbit / Q000098:blood supply*; D009918:Orbital Neoplasms / Q000000981:diagnostic imaging; D010690:Phlebography; D013924:Thrombophlebitis / Q000000981:diagnostic imaging; D014680:Veins