[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/) › Quadriceps tendon [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # Quadriceps tendon The quadriceps tendon is the broad tendon of the four front thigh muscles, attaching to the top of the kneecap; it straightens the knee. Official name: Tendon of quadriceps femoris muscle [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=lower_limb&select=quadriceps_tendon&side=r) Opens in the Durgical app, no sign-up needed. ## What it is A broad, thick tendon where the four quadriceps muscles join and attach to the top of the kneecap. ## What it does Carries the pull of the quadriceps through the kneecap to straighten the knee. ## Key points - Built in three layers: [rectus femoris](https://durgical.com/en/anatomy/rectus-femoris-muscle/) superficial, vastus medialis and lateralis in the middle, [vastus intermedius](https://durgical.com/en/anatomy/vastus-intermedius-muscle/) deep - Rupture usually happens just above the patella; risk is higher with [kidney](https://durgical.com/en/anatomy/kidney/) disease, diabetes and steroid use, and both sides may tear - Increasingly used as an ACL graft, with or without a patellar bone block ## Key facts **Attaches** Converging tendons of rectus femoris and the three vasti to base of patella **Function** Transmits quadriceps force to patella; continues below as patellar ligament **Tight in** Knee flexion, especially with hip extended ## Relations **Superficial** [Fascia lata](https://durgical.com/en/anatomy/fascia-lata/) and [skin](https://durgical.com/en/anatomy/skin/) **Deep** [Suprapatellar bursa](https://durgical.com/en/anatomy/suprapatellar-bursa/) (continuous with the knee joint) and the prefemoral fat pad over the [femur](https://durgical.com/en/anatomy/femur/) **Medial** [Vastus medialis](https://durgical.com/en/anatomy/vastus-medialis-muscle/) obliquus, whose aponeurosis continues as the [medial retinaculum](https://durgical.com/en/anatomy/medial-patellar-retinaculum/) **Lateral** [Vastus lateralis](https://durgical.com/en/anatomy/vastus-lateralis-muscle/), whose aponeurosis continues as the [lateral retinaculum](https://durgical.com/en/anatomy/lateral-patellar-retinaculum/) **Below** Base of the [patella](https://durgical.com/en/anatomy/patella/); superficial fibres continue over its front into the [patellar tendon](https://durgical.com/en/anatomy/patellar-ligament/) ## How to find it Just above the patella, felt as a broad firm band that hardens when the person tightens the thigh with the knee straight. ## Examination - Straight-leg raise: inability to lift the straight leg or to hold the knee fully extended against gravity suggests disruption of the extensor mechanism; a gap may be felt just above the patella ## On imaging Lateral X-ray after rupture: a low-riding patella (baja), soft-tissue swelling above it, sometimes small bone flecks from the upper pole. Ultrasound or MRI shows the gap and which layers are torn. A tooth sign (vertical spurs on the upper front of the patella on skyline views) marks enthesopathy. ## Common problems - Quadriceps tendinopathy: pain just above the kneecap with jumping or squatting. - Rupture, more common after age 40: the leg cannot be straightened against gravity. ## How it is diagnosed Physical exam (a gap above the kneecap, unable to lift the straight leg); ultrasound or MRI. ## Treatment - Tendinopathy: physical therapy and load management. - Complete rupture: surgical repair, usually soon after the injury. - A strip of this tendon can also be used as a graft for ACL reconstruction. ## Clinical notes - If the retinacula are intact, some active extension may remain despite a complete tendon tear, so the rupture is often missed - Acute complete ruptures are repaired early; delayed repairs are more difficult because the tendon retracts - On a lateral X-ray a low-riding patella (patella baja) points to a quadriceps tendon rupture, whereas a high-riding patella (patella alta) points to a patellar tendon rupture ## Anatomical variants - An extra muscle belly, the tensor of the vastus intermedius, lies between vastus lateralis and intermedius and can add a layer to the tendon; texts differ on how often ## Development The patella develops inside this tendon as the body's largest sesamoid bone; it starts as cartilage and ossifies in early childhood. Failure of one ossification centre to fuse leaves a bipartite patella, usually at the upper outer corner. ## Test yourself Think of the answer, then tap the question to see it. ## What are the three layers of the quadriceps tendon? Rectus femoris superficial, vastus medialis and lateralis in the middle, vastus intermedius deep. ## Where does the quadriceps tendon usually rupture, and which conditions raise the risk? Just above the patella; kidney disease, diabetes and steroid use raise the risk, and both sides may tear. ## Why is a complete quadriceps tendon rupture often missed? If the retinacula are intact, some active knee extension may remain. ## What does a lateral knee X-ray show after quadriceps tendon rupture? A low-riding patella (patella baja), soft-tissue swelling above it and sometimes small bone flecks from the upper pole. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/tendon-of-quadriceps-femoris-muscle/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** tendo musculi quadricipitis femoris TA2 2621 **Official Spanish (DeCS)** Tendón del músculo cuádriceps femoral DeCS D013710 **English (TA2)** Tendon of quadriceps femoris muscle ## Related - [Patella](https://durgical.com/en/anatomy/patella/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=14088); [Anatomy, Bony Pelvis and Lower Limb: Thigh Quadriceps Muscle](https://www.ncbi.nlm.nih.gov/books/NBK513334/); [8.4 Bones of the Lower Limb](https://openstax.org/books/anatomy-and-physiology-2e/pages/8-4-bones-of-the-lower-limb) (OpenStax (Rice University), 2022) · adapted, [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/). ## **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/tendon-of-quadriceps-femoris-muscle/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/tendon-of-quadriceps-femoris-muscle/