Lower limb

Quadriceps tendon and patellar ligament (Knee extensor apparatus)

Tendo musculi quadricipitis femoris et ligamentum patellae

Origin

Confluence of 4 quadriceps muscle heads onto the superior patellar pole, continuing from the inferior patellar pole as the patellar ligament

Insertion

Tibial tuberosity on the anterior proximal tibia

Function

Primary knee extension mechanism; patella acts as a anatomical fulcrum, increasing the quadriceps moment arm by 30–50%

Innervation

Femoral nerve (L2–L4)

Movement & chain

Drives active knee extension and eccentric deceleration during landing and stair descent

Palpation

Palpable superior and inferior to patella down to tibial tuberosity

Clinical

Patellar tendinopathy (Jumper's knee); Osgood-Schlatter disease (traction apophysitis in adolescents); acute extensor mechanism rupture (inability to perform straight leg raise - extensor lag).

Segmental innervation

L2–L4

In clinical practice

Straight leg raise test, Heavy Slow Resistance (HSR) protocol, and decline squat eccentric training for patellar tendinopathy

Region in the model

Lower limb