Intermediate root of inferior extensor retinaculum

The deep layer of inferior extensor retinaculum divides into the “intermediate root” and “medial root” of the inferior extensor retinaculum and attaches to the floor of the tarsal sinus. The intermediate root, which is the larger of the 2 roots, inserts on the posterolateral border of the tarsal sinus. The medial root attaches closely to the neck of the talus and then divides into a thin lateral component (LC, 5.7 ± 1.1 mm in width) and a broad medial component (MC, 16.5 ± 2.4 mm in width).