[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Anatomy](https://durgical.com/en/anatomy/) › [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) › Patellar tendon [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # Patellar tendon The patellar tendon runs from the kneecap to the shin bone; with the quadriceps it straightens the knee. Official name: Patellar ligament [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=lower_limb&select=patellar_tendon&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A broad, thick band (about 2.5–3 cm wide) from the lower tip of the kneecap to the bump on the front of the [tibia](https://durgical.com/en/anatomy/tibia/) (tibial tuberosity). ## What it does Carries the pull of the quadriceps to the shin bone, so the knee can straighten. ## Key points - Strictly a ligament (bone to bone), because the [patella](https://durgical.com/en/anatomy/patella/) is a sesamoid bone inside the [quadriceps tendon](https://durgical.com/en/anatomy/tendon-of-quadriceps-femoris-muscle/) - Patellar tendon rupture is typical under 40, quadriceps tendon rupture over 40; the patella rides high (alta) after a patellar tendon rupture - Its central third with a bone block at each end is the bone–patellar tendon–bone graft for ACL reconstruction - Insall–Salvati ratio (tendon length over patellar length) is about 1; above 1.2 means patella alta, below 0.8 patella baja ## Key facts **Attaches** Apex and lower margins of patella to tibial tuberosity **Function** Continuation of quadriceps tendon; transmits quadriceps pull to tibia to extend knee; tapped for knee jerk (L3–L4) **Tight in** Knee flexion; quadriceps contraction ## Relations **Superficial** [Subcutaneous infrapatellar bursa](https://durgical.com/en/anatomy/subcutaneous-infrapatellar-bursa/) over its lower part and the tibial tuberosity, then [skin](https://durgical.com/en/anatomy/skin/); the infrapatellar branch of the [saphenous nerve](https://durgical.com/en/anatomy/saphenous-nerve/) crosses it **Deep** Infrapatellar (Hoffa) fat pad and, just above its insertion, the deep infrapatellar bursa **Medial** [Medial retinaculum](https://durgical.com/en/anatomy/medial-patellar-retinaculum/) along its border **Lateral** [Lateral retinaculum](https://durgical.com/en/anatomy/lateral-patellar-retinaculum/) along its border ## How to find it With the knee bent to 90° and relaxed, it is felt as a broad firm band between the lower pole of the patella and the tibial tuberosity; it tightens when the quadriceps contracts. ## Examination - Single-leg decline squat: pain at the lower pole of the patella suggests patellar tendinopathy - Palpation with the knee straight: tenderness at the lower pole that eases when the knee is flexed is typical of tendinopathy ## On imaging Lateral X-ray: patella alta after rupture; fragments at the tuberosity in Osgood–Schlatter. Ultrasound in tendinopathy: a thickened, darker (hypoechoic) proximal tendon, often with new vessels on Doppler. MRI: thickening and bright signal in the deep proximal fibres. ## Common problems - Tendinitis from jumping and running (jumper's knee). - Rupture (uncommon): the leg cannot be straightened against gravity. ## How it is diagnosed Physical exam; ultrasound or MRI. ## Treatment - Tendinitis: rest from the painful activity, physical therapy and load management. - Complete rupture: surgical repair. - Bone–patellar tendon–bone (BTB) graft: the central third of this tendon, with a small block of bone from the kneecap and the tibia, is a classic graft for ACL reconstruction. It can come from the patient or from a donor. ## Clinical notes - BPTB graft harvest can leave anterior knee pain, pain when kneeling and, rarely, a patellar fracture - Sinding-Larsen–Johansson disease: traction apophysitis at the lower pole of the patella in adolescents, the upper counterpart of Osgood–Schlatter - Scarring after surgery or immobilization can shorten the tendon (patella baja), limiting knee motion ## Development The tibial tuberosity ossifies from a [tongue](https://durgical.com/en/anatomy/tongue/) -like extension of the proximal tibial epiphysis; repeated pull during the growth spurt causes Osgood–Schlatter disease. ## Related conditions - [Osgood–Schlatter Disease](https://durgical.com/en/conditions/osgood-schlatter-disease/) - [Patellar Tendinopathy](https://durgical.com/en/conditions/patellar-tendinopathy/) ## Test yourself Think of the answer, then tap the question to see it. ## Why is the patellar tendon strictly a ligament? It joins bone to bone (patella to tibial tuberosity), because the patella is a sesamoid bone inside the quadriceps tendon. ## Which extensor tendon ruptures typically under 40, and what happens to the patella? The patellar tendon; the patella rides high (patella alta). ## What Insall–Salvati ratios define patella alta and patella baja? Normal is about 1; above 1.2 is patella alta, below 0.8 patella baja. ## Which reflex is tested by tapping the patellar tendon, and at which roots? The knee jerk, L3–L4. ## What is Sinding-Larsen–Johansson disease? Traction apophysitis at the lower pole of the patella in adolescents, the upper counterpart of Osgood–Schlatter disease. [Add to my cards (5)](https://durgical.app/estudiar/?add=/en/anatomy/patellar-ligament/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** ligamentum patellae TA2 2622 **Official Spanish (DeCS)** Ligamento rotuliano DeCS D017847 **English (TA2)** Patellar ligament **Also called** infrapatellar portion of quadriceps tendon ## Related - [Patella](https://durgical.com/en/anatomy/patella/) - [Infrapatellar fat pad](https://durgical.com/en/anatomy/infrapatellar-fat-pad/) - [Infrapatellar bursae](https://durgical.com/en/anatomy/subcutaneous-infrapatellar-bursa/) - [Tibia](https://durgical.com/en/anatomy/tibia/) - [Rectus femoris](https://durgical.com/en/anatomy/rectus-femoris-muscle/) - [Vastus medialis](https://durgical.com/en/anatomy/vastus-medialis-muscle/) - [Vastus lateralis](https://durgical.com/en/anatomy/vastus-lateralis-muscle/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=31206&filter=ths_termall&q=Ligamento%20Rotuliano); [Anatomy, Bony Pelvis and Lower Limb: Thigh Quadriceps Muscle](https://www.ncbi.nlm.nih.gov/books/NBK513334/). ## **Spotted a mistake?** We are always improving for the community. Tell us what is wrong and our team will review it. Report a mistake Representative model, for educational purposes only. --- Source: https://durgical.com/en/anatomy/patellar-ligament/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/patellar-ligament/