[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/) › Vastus lateralis [Muscular system](https://durgical.com/en/anatomy/system/muscular-system/) · [Lower limb](https://durgical.com/en/anatomy/region/lower-limb/) # Vastus lateralis The vastus lateralis is the large outer muscle of the quadriceps, on the side of the thigh; it straightens the knee. Official name: Vastus lateralis muscle [See in 3D →](https://durgical.app/?from=durgipedia&lang=en#region=lower_limb&select=vastus_lateralis&side=r) Opens in the Durgical app, no sign-up needed. ## What it is The largest quadriceps muscle, on the outer front of the thigh. ## What it does Straightens the knee. ## Key points - Recommended site for intramuscular injection in infants and young children: the anterolateral thigh, over the middle third of the muscle - Classic site for muscle biopsy: large, superficial and away from the major nerves and vessels - Its pull on the [patella](https://durgical.com/en/anatomy/patella/) is lateral; the oblique fibres of the [vastus medialis](https://durgical.com/en/anatomy/vastus-medialis-muscle/) balance it ## Key facts **Origin** Greater trochanter; upper intertrochanteric line; gluteal tuberosity; lateral lip of linea aspera **Insertion** Lateral patella via [quadriceps tendon](https://durgical.com/en/anatomy/tendon-of-quadriceps-femoris-muscle/); tibial tuberosity via [patellar ligament](https://durgical.com/en/anatomy/patellar-ligament/); [lateral patellar retinaculum](https://durgical.com/en/anatomy/lateral-patellar-retinaculum/) **Action** Extends knee **Nerve** [Femoral nerve](https://durgical.com/en/anatomy/femoral-nerve/) (L2–L4) **Blood supply** Lateral circumflex femoral artery (descending branch); [deep femoral artery](https://durgical.com/en/anatomy/deep-femoral-artery/) branches ## Relations **Superficial** [Iliotibial tract](https://durgical.com/en/anatomy/iliotibial-tract/) and [fascia lata](https://durgical.com/en/anatomy/fascia-lata/), which cover its outer surface **Medial** [Rectus femoris](https://durgical.com/en/anatomy/rectus-femoris-muscle/) in front; the descending branch of the lateral circumflex [femoral artery](https://durgical.com/en/anatomy/femoral-artery/) runs in the groove between the two **Deep** [Vastus intermedius](https://durgical.com/en/anatomy/vastus-intermedius-muscle/), partly fused with it, and the lateral surface of the femoral shaft **Behind** Lateral intermuscular septum, which separates it from the short head of the biceps femoris; [perforating arteries](https://durgical.com/en/anatomy/perforating-femoral-arteries/) cross the septum near the linea aspera ## How to find it With the knee straight and the thigh tightened, it forms the bulk of the outer front of the thigh, from the greater trochanter down to the outer edge of the patella. The infant injection site is the middle third of the line from the greater trochanter to the lateral femoral condyle, on the anterolateral surface. ## On imaging Ultrasound shows it as the large muscle of the anterolateral thigh, with fine bright fibre lines; its thickness is measured to follow muscle wasting in critical illness or ageing. Ultrasound also guides a muscle biopsy and finds a haematoma or abscess at an injection site. MRI shows strains, contusions and the muscle oedema of myositis, where it helps pick the biopsy site. ## Common problems - Strains (pulled muscle) from sprinting or kicking; bruising from a direct blow. - Weakness and shrinking after knee injury or surgery, which rehabilitation works to rebuild. ## How it is diagnosed Physical exam; ultrasound or MRI for significant injuries. ## Treatment - Rest, ice, then progressive strengthening with a physical therapist. ## Clinical notes - Anterolateral thigh (ALT) flap: the [skin](https://durgical.com/en/anatomy/skin/) perforators of the descending branch of the lateral circumflex femoral artery usually pass through this muscle, so it is dissected during the harvest - Lateral and posterolateral approaches to the femoral shaft lift or split it; the perforating vessels near the lateral intermuscular septum have to be controlled - Tight lateral structures (vastus lateralis, lateral retinaculum, iliotibial tract) add to lateral tilt and maltracking of the patella ## Anatomical variants - A lower oblique part (vastus lateralis obliquus) with its own insertion can be distinguished; the cited review found two insertional parts in about 3 of 5 limbs - An extra muscle between the vastus lateralis and the vastus intermedius, the tensor of the vastus intermedius, is described in several forms ## Development A dorsal muscle mass derivative, supplied by the femoral nerve; it ends up on the front and outer thigh because the [lower limb](https://durgical.com/en/anatomy/region/lower-limb/) rotates medially during the seventh week of development. ## Related conditions - [Tarui disease (muscle phosphofructokinase deficiency)](https://durgical.com/en/conditions/tarui-disease/) - [Cori disease (glycogen storage disease type III)](https://durgical.com/en/conditions/cori-disease/) - [McArdle disease (glycogen storage disease type V)](https://durgical.com/en/conditions/mcardle-disease/) - [Carnitine palmitoyltransferase II (CPT-II) deficiency](https://durgical.com/en/conditions/carnitine-palmitoyltransferase-ii-deficiency/) - [Myoadenylate deaminase deficiency (AMP deaminase deficiency)](https://durgical.com/en/conditions/myoadenylate-deaminase-deficiency/) - [Frailty syndrome](https://durgical.com/en/conditions/frailty-syndrome/) - [Sarcopenia](https://durgical.com/en/conditions/sarcopenia/) - [Soft tissue sarcomas (liposarcoma, leiomyosarcoma, rhabdomyosarcoma)](https://durgical.com/en/conditions/soft-tissue-sarcomas/) - [Pyomyositis (including psoas abscess)](https://durgical.com/en/conditions/pyomyositis/) - [Rhabdomyolysis](https://durgical.com/en/conditions/rhabdomyolysis/) - [Lambert-Eaton myasthenic syndrome](https://durgical.com/en/conditions/lambert-eaton-myasthenic-syndrome/) - [Critical illness polyneuropathy and myopathy (ICU-acquired weakness)](https://durgical.com/en/conditions/critical-illness-polyneuropathy-and-myopathy/) - [Periodic paralyses (hypokalaemic, hyperkalaemic, thyrotoxic)](https://durgical.com/en/conditions/periodic-paralyses/) - [Inflammatory myopathies (dermatomyositis, polymyositis)](https://durgical.com/en/conditions/inflammatory-myopathies/) - [Malignant hyperthermia](https://durgical.com/en/conditions/malignant-hyperthermia/) - [Patellar fracture](https://durgical.com/en/conditions/patellar-fracture/) - [Femoral shaft fracture](https://durgical.com/en/conditions/femoral-shaft-fracture/) ## Test yourself Think of the answer, then tap the question to see it. ## Where is the recommended intramuscular injection site in infants and young children, and which muscle lies there? The anterolateral thigh, over the middle third of the vastus lateralis (middle third of the line from the greater trochanter to the lateral femoral condyle). ## Why is the vastus lateralis a classic site for muscle biopsy? It is large and superficial and lies away from the major nerves and vessels of the thigh. ## Which flap is raised through the vastus lateralis, and on which artery is it based? The anterolateral thigh (ALT) flap: the skin perforators of the descending branch of the lateral circumflex femoral artery usually pass through the vastus lateralis. ## In which direction does the vastus lateralis pull the patella, and what balances it? Laterally; the oblique fibres of the vastus medialis balance it. Tight lateral structures add to lateral tilt and maltracking of the patella. [Add to my cards (4)](https://durgical.app/estudiar/?add=/en/anatomy/vastus-lateralis-muscle/) Educational information, not medical advice. For any symptom, see a health professional. ## Its names **Official Latin (TA2)** musculus vastus lateralis TA2 2618 **Official Spanish (DeCS)** Músculo vasto lateral DeCS D052097 **English (TA2)** Vastus lateralis muscle **Also called** musculus vastus fibularis ## Related - [IT band](https://durgical.com/en/anatomy/iliotibial-tract/) - [Vastus intermedius](https://durgical.com/en/anatomy/vastus-intermedius-muscle/) - [Femoral nerve](https://durgical.com/en/anatomy/femoral-nerve/) - [Femoral artery](https://durgical.com/en/anatomy/femoral-artery/) - [Circumflex femoral arteries](https://durgical.com/en/anatomy/medial-circumflex-femoral-artery/) - [Perforating arteries](https://durgical.com/en/anatomy/perforating-femoral-arteries/) - [Vastus lateralis tendon](https://durgical.com/en/anatomy/tendon-of-vastus-lateralis/) - [Femur](https://durgical.com/en/anatomy/femur/) Sources: Terminologia Anatomica (TA2); [DeCS](https://decs.bvsalud.org/es/ths/resource/?id=50351&filter=ths_termall&q=M%C3%BAsculo%20Cu%C3%A1driceps); [Anatomy, Bony Pelvis and Lower Limb: Vastus Lateralis Muscle](https://www.ncbi.nlm.nih.gov/books/NBK532309/); [Anatomy, Bony Pelvis and Lower Limb: Thigh Quadriceps Muscle](https://www.ncbi.nlm.nih.gov/books/NBK513334/); [8.5 Development of the Appendicular Skeleton](https://openstax.org/books/anatomy-and-physiology-2e/pages/8-5-development-of-the-appendicular-skeleton) (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/vastus-lateralis-muscle/ License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/anatomy/vastus-lateralis-muscle/