Medial border of patella

The medial border of the patella is characterized by the attachment sites of several key soft tissue structures that contribute to patellar stability. The most prominent structure is the medial patellofemoral ligament (MPFL), which inserts onto the superomedial aspect of the patella. The MPFL is an hourglass-shaped structure that fans out at both ends and attaches broadly to the medial patella, rather than at a single point, with its patellar insertion typically located at the upper half of the medial border. 

Inferiorly, the medial patellotibial ligament (MPTL) and medial patellomeniscal ligament (MPML) share a common patellar insertion at the distal medial border of the patella, approximately 3–6 mm proximal to the distal pole. The MPTL and MPML are visible thickenings of the deep medial retinaculum and are oriented obliquely, contributing to patellar stabilization, especially in flexion. 

Additionally, the medial quadriceps tendon-femoral ligament (MQTFL), a component of the medial patellofemoral complex, attaches to the medial aspect of the distal quadriceps tendon and the medial border of the patella, with its midpoint at the junction of the medial quadriceps tendon and the articular surface of the patella.