Fascia · Knee

Medial patellar retinaculum

Retinaculum patellae mediale

The matching apron on the inner side of the kneecap, formed by the aponeurosis of vastus medialis spreading forwards over the patella and down to the front of the tibia. It merges with the joint capsule and, in its deeper layer, with the fibres that run from the inner side of the femur to the edge of the patella. It resists the kneecap being dragged outwards — the direction the quadriceps naturally pulls it, because the thigh bone slants inwards towards the knee — and the medial patellofemoral fibres of its deep layer are the strongest part of that restraint.