[TA] slightly reinforced portion of the external oblique aponeurosis, formed by fibers derived from the medial portion of the inguinal ligament of one side that run medially and slightly superiorly, defining the inferior margin of the superficial inguinal ring; the fibers then pass on the deep aspect of the ipsilateral medial crus, crossing the linea alba and running within the contralateral aponeurosis to course parallel and superior to the contralateral inguinal ligament.aponeurosis of external oblique (muscle). SYN: ligamentum reflexum [TA], Colles ligament, fascia triangularis abdominis, reflex ligament, triangular fascia.