Lower limb

Knee joint capsule, synovial membrane, and infrapatellar (Hoffa's) fat pad

Capsula articularis, membrana synovialis genus et corpus adiposum infrapatellare (Hoffa)

Origin

Distal femur, patellar borders, and proximal tibia

Insertion

Tibial plateau, patellar ligament, and intercondylar notch

Function

Largest synovial joint capsule in the body; secretes synovial lubricant; Hoffa's fat pad acts as a dynamic cushion and sensory endocrine organ rich in nociceptive fibers

Innervation

Femoral, tibial, common fibular, and obturator nerves

Movement & chain

Folds and expands smoothly during full flexion (suprapatellar pouch extends up to 5 cm above patella)

Palpation

Hoffa fat pad is palpable adjacent to patellar tendon beneath patellar apex

Clinical

Hoffa's disease (infrapatellar fat pad impingement/hypertrophy; positive Hoffa test); knee joint effusion (patellar ballottement test); synovial plica syndrome.

Segmental innervation

L2–S1

In clinical practice

Patellar ballottement test for effusion, Hoffa test, arthrocentesis, and offloading tape for fat pad irritation

Region in the model

Lower limb