The patellar tendon is really a tendon of the quadriceps muscle, where the patella bone is recessed into this tendon, splitting the tendon anatomically into quads tendon above the patella and patellar tendon below. A bone situated inside a tendon like this is called a 'sesamoid' bone.
The bony bump on the tibia where the tendon attaches is called the tibial tubercle.
The 'extensor mechanism'
The patellar tendon is the lower part of a chain of structures known as the extensor mechanism, which reaches from the hip to the shin.
The extensor mechanism functions as a unit to straighten the knee and hold the person upright.
Patellar tendon problems
The patellar tendon is really important as it is the lower tether for the whole extensor mechanism, and it is therefore subject to a lot of stress.
Problems that can arise here include:
- Patellar malalignment - where the tendon attachment does not align well with the groove in which the patella is contained.
- Osgood-Schlatter's disorder - also called Juvenile traction osteochondritis - where repeated jumping activities in a young person put stress on the attachment of the tendon to the tibia at the tibial tuberosity.
- Patellar tendinitis - where overuse in an older person leads to painful mucoid degeneration inside the tendon itself.
- Patellar tendon rupture - where extreme sports can cause the patellar tendon to break.
Relevant links on KNEEguru
A-Z Keywords
Osgood Schlatter's disease, Patellar tendon rupture, Patellar tendinopathy, BTB, Bone patellar-tendon bone, Extensor mechanism, Tibial tuberosity, Traction apophysitis, Juvenile traction osteochondritis, Tibial tubercle avulsion, Bone-patellar tendon-bone graft
Contributions by experts
- Dr Lars Blønd - TT-TG distance
- Dr (Mr) Charles Willis-Owen - Patellar tendinitis - part of a course on Lower Limb Overuse Injur
Forum discussions
- please give advice an graft selection, im freaking out. - Patients discuss options - including patellar tendon - for reconstructing their torn cruciate ligament.
- Please not the other knee as well!!!! - A wide-ranging discussion about patellar tendinitis and other problems in and around the patellar tendon.