{"schemaVersion":1,"id":"en-anatomy-tensor-fasciae-latae","type":"anatomy","pillar":"body","locale":"en","translationGroupId":"anatomy-tensor-fasciae-latae","slugPath":"body/muscles/tensor-fasciae-latae","title":"Tensor fasciae latae","shortTitle":"Tensor fasciae latae","summary":"A short muscle that attaches not to a bone but to a fibrous band. That band runs down to the tibia and carries its pull along the whole length of the thigh.","level":"intermediate","estimatedMinutes":8,"synonyms":["tensor fasciae latae","TFL","iliotibial band","iliotibial tract","fascia lata","outer thigh"],"blocks":[{"id":"b1","type":"heading","level":2,"text":"A muscle that touches no bone below","anchor":"a-muscle-that-touches-no-bone-below"},{"id":"b2","type":"paragraph","content":[{"kind":"text","value":"Tensor fasciae latae is short — around fifteen centimetres — and sits at the front of the outer hip. What sets it apart is its insertion: it attaches not to a bone, but to a fibrous band."}]},{"id":"b3","type":"paragraph","content":[{"kind":"text","value":"That band, the iliotibial band, runs down the whole outer face of the thigh and attaches to the tibia, below the "},{"kind":"link","value":"knee","href":"/en/body/joints/knee","external":false},{"kind":"text","value":". The muscle therefore pulls on a cord, and the cord carries the pull far beyond it."}]},{"id":"b4","type":"definition","term":"Iliotibial band","definition":"The fibrous thickening of the outer face of the fascia lata, the connective wrapping of the thigh. It runs from the iliac crest to the tibia and receives the insertions of tensor fasciae latae and part of gluteus maximus.","alsoKnownAs":["iliotibial tract"]},{"id":"b5","type":"heading","level":3,"text":"Origin","anchor":"origin"},{"id":"b6","type":"paragraph","content":[{"kind":"text","value":"It arises from the front part of the iliac crest and the anterior superior iliac spine, the bony prominence you can feel at the front of the hip."}]},{"id":"b7","type":"heading","level":3,"text":"Insertion","anchor":"insertion"},{"id":"b8","type":"paragraph","content":[{"kind":"text","value":"After a few centimetres its fibres run into the iliotibial band, at the junction of the upper third and lower two-thirds of the thigh."}]},{"id":"b9","type":"heading","level":3,"text":"Nerve supply and palpable landmarks","anchor":"nerve-supply-and-palpable-landmarks"},{"id":"b10","type":"paragraph","content":[{"kind":"text","value":"The nerve supply comes from the superior gluteal nerve, from the L4 to S1 roots — the same as "},{"kind":"link","value":"gluteus medius","href":"/en/body/muscles/gluteus-medius","external":false},{"kind":"text","value":". The muscle can be felt at the front of the hip, just below the iliac spine, and hardens when you lift the leg sideways."}]},{"id":"b11","type":"heading","level":2,"text":"What tensor fasciae latae does","anchor":"what-tensor-fasciae-latae-does"},{"id":"b12","type":"paragraph","content":[{"kind":"text","value":"It acts on two joints without directly touching either from below."}]},{"id":"b13","type":"list","ordered":false,"items":[[{"kind":"strong","value":"Hip abduction"},{"kind":"text","value":": it takes the thigh outwards, alongside "},{"kind":"link","value":"gluteus medius","href":"/en/body/muscles/gluteus-medius","external":false},{"kind":"text","value":"."}],[{"kind":"strong","value":"Hip flexion"},{"kind":"text","value":": its forward origin gives it a flexing component."}],[{"kind":"strong","value":"Medial rotation"},{"kind":"text","value":": it turns the thigh inwards."}],[{"kind":"strong","value":"Action on the knee"},{"kind":"text","value":": through the band, it takes part in sideways knee stability, with a contribution that changes with the angle of flexion."}]]},{"id":"b14","type":"evidence","level":"established","statement":"Tensor fasciae latae transmits its pull to the tibia through the iliotibial band, with no bony insertion of its own at the knee.","detail":"Descriptive anatomy and kinesiology describe the same arrangement. The exact share of the band in sideways knee stability varies with the angle of flexion and with measurement method.","referenceIds":["standring2020","neumann2016"]},{"id":"b15","type":"heading","level":2,"text":"The first fascia visible in a scene","anchor":"the-first-fascia-visible-in-a-scene"},{"id":"b16","type":"paragraph","content":[{"kind":"text","value":"The "},{"kind":"link","value":"fascia","href":"/en/body/fascia","external":false},{"kind":"text","value":" page explains that this tissue appears in no model, for want of a separate mesh in the sources used. The iliotibial band is the exception: it is thick and distinct enough to exist as a separate part."}]},{"id":"b17","type":"paragraph","content":[{"kind":"text","value":"It is therefore, in the whole corpus, the only fascial structure that can be seen. It illustrates well what the fascia page describes in general: a wrapping that is not passive, that muscles attach to and through which force is transmitted."}]},{"id":"b18","type":"heading","level":2,"text":"The movements it takes part in","anchor":"the-movements-it-takes-part-in"},{"id":"b19","type":"paragraph","content":[{"kind":"text","value":"It works in the "},{"kind":"link","value":"lunge","href":"/en/movements/lunge","external":false},{"kind":"text","value":" and in every reduced-base position, where sideways control of the pelvis becomes a constraint. It also works in walking and running, on every single-leg stance, with "},{"kind":"link","value":"gluteus medius","href":"/en/body/muscles/gluteus-medius","external":false},{"kind":"text","value":"."}]},{"id":"b20","type":"heading","level":2,"text":"Related structures","anchor":"related-structures"},{"id":"b21","type":"heading","level":3,"text":"Synergists","anchor":"synergists"},{"id":"b22","type":"list","ordered":false,"items":[[{"kind":"link","value":"Gluteus medius","href":"/en/body/muscles/gluteus-medius","external":false},{"kind":"text","value":" shares its nerve supply and its abduction role."}],[{"kind":"text","value":"The upper fibres of "},{"kind":"link","value":"gluteus maximus","href":"/en/body/muscles/glutes","external":false},{"kind":"text","value":" also end on the band, from behind."}],[{"kind":"text","value":"The "},{"kind":"link","value":"iliopsoas","href":"/en/body/muscles/iliopsoas","external":false},{"kind":"text","value":" accompanies its flexing component."}]]},{"id":"b23","type":"heading","level":3,"text":"Antagonists","anchor":"antagonists"},{"id":"b24","type":"list","ordered":false,"items":[[{"kind":"text","value":"The "},{"kind":"link","value":"hip adductors","href":"/en/body/muscles/hip-adductors","external":false},{"kind":"text","value":" bring the thigh back towards the midline."}],[{"kind":"text","value":"The lateral hip rotators oppose its medial rotation component."}]]},{"id":"b25","type":"heading","level":2,"text":"Seeing the tensor and its band","anchor":"seeing-the-tensor-and-its-band"},{"id":"b26","type":"scene3d","sceneId":"carte-corporelle","title":"Tensor fasciae latae and its band","intro":"The scene shows the muscle at the front of the hip and the fibrous band running down from it to the tibia. Seen from the front, the band is almost edge-on: it appears as a line along the outer border of the thigh rather than as a sheet. The two are also merged into a single volume, the boundary between fleshy belly and band not being drawn. Without the 3D, the picture fits in one sentence: a short muscle at the top, a long strap below.","initialStepId":"vue-anterieure","accessibility":{"textAlternative":"A three-dimensional diagram of a standing human body, arms by the sides, built from simplified paper-coloured volumes. Twelve priority muscle groups are laid over this outline in terracotta: at the front, pectoralis major, the deltoid, biceps brachii, the abdominal wall and the quadriceps; at the back, the trapezius, latissimus dorsi, the erector spinae, triceps brachii, the glutes, the hamstrings and the calves. A simplified skeleton — skull, spine, ribcage, pelvis, humerus, femur and tibia — can be shown beneath the outline to reveal the bony levers these muscles pull on. Each group is selectable and opens its own reference page. This is a teaching diagram with stylised volumes, not an exact anatomical reconstruction.","structures":[{"label":"Pectoralis major","description":"A thick sheet running from the clavicle, the sternum and the upper costal cartilages to the lateral lip of the bicipital groove of the humerus. It draws the arm towards the midline and forwards, and drives horizontal pushing.","href":"/en/body/muscles/pectoralis-major"},{"label":"Deltoids","description":"Three heads — anterior, lateral and posterior — running from the clavicle, the acromion and the spine of the scapula to the deltoid tuberosity of the humerus. Together they raise the arm; separately they carry it forwards, out to the side or backwards.","href":"/en/body/muscles/deltoids"},{"label":"Biceps brachii","description":"Two heads arising from the scapula — the supraglenoid tubercle and the coracoid process — joining on the radial tuberosity. It flexes the elbow and supinates the forearm, and contributes to every pulling movement.","href":"/en/body/muscles/biceps-brachii"},{"label":"Abdominal wall","description":"Rectus abdominis, the external and internal obliques and transversus, running from the ribs and sternum to the pubis and iliac crest. They flex and rotate the trunk and, above all, stabilise the spine by regulating intra-abdominal pressure.","href":"/en/body/muscles/abdominal-wall"},{"label":"Quadriceps","description":"Four heads — rectus femoris, vastus lateralis, vastus medialis and vastus intermedius — joining through the quadriceps tendon onto the patella and then the tibial tuberosity. They extend the knee, and rectus femoris also flexes the hip.","href":"/en/body/muscles/quadriceps"},{"label":"Trapezius","description":"A diamond-shaped muscle spanning from the occiput and the cervical and thoracic spinous processes to the clavicle, the acromion and the spine of the scapula. Its upper, middle and lower portions elevate, retract and depress the scapula.","href":"/en/body/muscles/trapezius"},{"label":"Latissimus dorsi","description":"A broad fan arising from the lower thoracic vertebrae, the thoracolumbar fascia, the iliac crest and the lowest ribs, converging on the bicipital groove of the humerus. It pulls the arm down and back, and drives vertical pulling.","href":"/en/body/muscles/latissimus-dorsi"},{"label":"Erector spinae","description":"Muscular columns — iliocostalis, longissimus and spinalis — running from the sacrum and iliac crest to the ribs, the vertebrae and the skull, on either side of the spinous processes. They extend the spine and control the trunk as it lowers.","href":"/en/body/muscles/erector-spinae"},{"label":"Triceps brachii","description":"Three heads — long, lateral and medial — arising from the scapula and the back of the humerus and joining on the olecranon of the ulna. It extends the elbow, and its long head also assists shoulder extension.","href":"/en/body/muscles/triceps-brachii"},{"label":"Glutes","description":"Gluteus maximus, medius and minimus, arising from the iliac wing and the sacrum and inserting on the femur and the iliotibial tract. They extend, abduct and rotate the hip, and drive the pelvis upright in the hinge and the squat.","href":"/en/body/muscles/glutes"},{"label":"Hamstrings","description":"Biceps femoris, semitendinosus and semimembranosus, running from the ischial tuberosity to the tibia and fibula. They extend the hip and flex the knee, and control the trunk as it lowers in the hip hinge.","href":"/en/body/muscles/hamstrings"},{"label":"Calves","description":"The gastrocnemius and soleus, joining through the Achilles tendon onto the calcaneus. They plantarflex the ankle, and the gastrocnemius, which crosses the knee, also assists knee flexion.","href":"/en/body/muscles/calves"},{"label":"Rotator cuff","description":"Four short muscles running from the shoulder blade to the top of the humerus. Their tendons merge into a sheet that holds the head of the bone against its socket while the deltoid moves the arm.","href":"/en/body/muscles/rotator-cuff"},{"label":"Serratus anterior","description":"A sheet hooked onto the upper ribs by triangular slips, passing under the shoulder blade and attaching to its inner border. It holds the blade against the ribcage and rotates it.","href":"/en/body/muscles/serratus-anterior"},{"label":"Iliopsoas","description":"The only muscle linking the lumbar spine directly to the femur. It descends from the vertebrae and the iliac fossa, curves around the rim of the pelvis and attaches to the lesser trochanter.","href":"/en/body/muscles/iliopsoas"},{"label":"Hip adductors","description":"Five muscles running from the pubis to the back of the femur in overlapping layers. They draw the thigh towards the midline and control the pelvis in single-leg stance.","href":"/en/body/muscles/hip-adductors"},{"label":"Forearm muscles","description":"Masses gathered near the elbow, continued by long tendons to the wrist and fingers. They drive the hand from a distance and carry grip strength.","href":"/en/body/muscles/forearm"},{"label":"Tibialis anterior","description":"A muscle pressed against the outer surface of the tibia, its tendon swinging towards the inside of the foot. It lifts the toes on every step and brakes the forefoot after heel strike.","href":"/en/body/muscles/tibialis-anterior"},{"label":"Diaphragm","description":"A muscular dome running from the lower border of the ribs, the sternum and the lumbar vertebrae to a central tendon. As it contracts it descends, the chest gains volume and air enters: it is the engine of quiet breathing, and the ceiling of the abdominal cavity.","href":"/en/body/muscles/diaphragm"}],"steps":[{"id":"vue-anterieure","title":"Anterior view","body":"The front of the body. Pectoralis major covers the upper chest, the deltoid caps the shoulder, the biceps fills the front of the arm, the abdominal wall links the ribs to the pelvis, and the quadriceps fills the front of the thigh. Further out on the limbs, the forearm muscles drive the wrist and hand, and tibialis anterior lifts the foot."},{"id":"vue-posterieure","title":"Posterior view","body":"The back of the body. The trapezius links the neck to the shoulder blades, the latissimus dorsi fans down to the pelvis, the erector spinae flank the spine, and the triceps fills the back of the arm. Glutes, hamstrings and calves form the posterior chain from hip to ankle."},{"id":"plan-profond","title":"Deep and medial muscles","body":"Beneath the visible groups work muscles no silhouette shows. The rotator cuff holds the head of the humerus against the shoulder blade, serratus anterior keeps the shoulder blade flat on the ribcage, the iliopsoas links the lumbar spine to the femur, and the adductors fill the inner thigh. Deeper still, the diaphragm closes the trunk as a dome, inside the ribs. They orient and stabilise more than they move."},{"id":"chaine-de-poussee","title":"Pushing chain","body":"In a push, force starts at the ground, travels through the quadriceps and the abdominal wall, and then pectoralis major, the anterior deltoid and the triceps drive the load away from the trunk. The skeleton acts as the lever: no group works alone, and the quality of the movement comes from their sequencing."},{"id":"chaine-de-tirage","title":"Pulling chain","body":"In a pull, the latissimus dorsi and trapezius bring the arm and shoulder blade towards the trunk while the biceps flexes the elbow. Glutes, hamstrings and erector spinae hold the pelvis and spine so that force transfers without the trunk collapsing."}],"license":"Z-Anatomy et BodyParts3D — CC-BY-SA 4.0"}},{"id":"b27","type":"heading","level":2,"text":"What the model simplifies","anchor":"what-the-model-simplifies"},{"id":"b28","type":"callout","tone":"limit","title":"A band without its wrapping","content":[[{"kind":"text","value":"The iliotibial band is the lateral thickening of the fascia lata, which wraps the whole thigh. Only that lateral part exists as a distinct piece in the sources: the rest of the wrapping is not represented."}],[{"kind":"text","value":"The muscle and the band are also rendered as a single volume, although the transition from fleshy to fibrous tissue is abrupt."}]]},{"id":"b29","type":"heading","level":2,"text":"A subject that calls for care","anchor":"a-subject-that-calls-for-care"},{"id":"b30","type":"callout","tone":"caution","title":"What this page does not say","content":[[{"kind":"text","value":"Iliotibial band syndrome is a frequent reason for consultation among runners, and its mechanisms are debated. Describing the anatomy of the structure establishes neither its causes nor grounds for attributing a pain to it."}],[{"kind":"text","value":"Body Lab proposes here no exercise, no stretch and no technique. Pain on the outer side of the knee or hip that returns with effort belongs to a health professional."}]]},{"id":"b31","type":"heading","level":2,"text":"Sources","anchor":"sources"},{"id":"b32","type":"sourceList","title":"Main sources","referenceIds":["standring2020","neumann2016"]},{"id":"b33","type":"shapierAction","actionId":"exercises-clamshells","label":"Train tensor fasciae latae with clamshells","description":"Training tensor fasciae latae through hip abduction happens in Shapier with clamshells; Body Lab only explains what this muscle does.","webTarget":"https://shapier.app/en/exercises/clamshells","appTarget":"shapier://exercises/clamshells"},{"id":"b34","type":"quiz","title":"Check my understanding","questions":[{"id":"q1","prompt":"What does tensor fasciae latae insert onto?","choices":[{"id":"q1c1","label":"The iliotibial band, which carries its pull down to the tibia","correct":true,"explanation":"That is what sets the muscle apart: it does not insert on a bone but on a fibrous band running down to the tibia."},{"id":"q1c2","label":"Directly onto the tibia, below the knee","correct":false,"explanation":"Plausible, because the effect of its pull is felt there, but the page states it has no bony insertion of its own at the knee: it is the band that attaches there."},{"id":"q1c3","label":"Onto the femur, at the lower end of the thigh","correct":false,"explanation":"Its fibres run into the band at the junction of the upper third and lower two-thirds of the thigh, never onto the thigh bone."}]},{"id":"q2","prompt":"Why is the iliotibial band the only fascial structure visible in the corpus scenes?","choices":[{"id":"q2c1","label":"Because it is thick and distinct enough to exist as a separate part","correct":true,"explanation":"The fascia page explains that this tissue appears in no model for want of a separate mesh; the band is the exception."},{"id":"q2c2","label":"Because fascia appears in every anatomical model","correct":false,"explanation":"It is the opposite: the page recalls that fascia appears in no model, and the band is the sole exception."},{"id":"q2c3","label":"Because it was drawn specially for this page","correct":false,"explanation":"The page says nothing of the sort: it exists as a distinct piece in the sources used, with only its lateral part represented."}]},{"id":"q3","prompt":"What should you take away from what the page says about iliotibial band syndrome?","choices":[{"id":"q3c1","label":"That describing the anatomy of the structure establishes neither its causes nor grounds for attributing a pain to it","correct":true,"explanation":"The page sticks to anatomy and refers pain that returns with effort to a health professional."},{"id":"q3c2","label":"That it is caused by a muscle that is too short in runners","correct":false,"explanation":"The page says its mechanisms are debated and declines to conclude: no cause is asserted anywhere in the text."},{"id":"q3c3","label":"That exercises and stretches are enough to treat it","correct":false,"explanation":"The page proposes here no exercise, no stretch and no technique: that is not its purpose."}]}]},{"id":"b35","type":"relatedContent","title":"Read next","targetIds":["en-anatomy-gluteus-medius","en-mechanism-fascia","en-anatomy-knee-joint"]}],"relations":[{"type":"uses-structure","targetId":"en-anatomy-gluteus-medius"},{"type":"explains","targetId":"en-mechanism-fascia"},{"type":"produces-movement","targetId":"en-movement-lunge"},{"type":"next-step","targetId":"en-anatomy-knee-joint"}],"authors":["equipe-editoriale-shapier"],"reviewers":["Thanh Chau"],"references":[{"id":"standring2020","authors":"Standring S","year":2020,"title":"Gray's Anatomy: The Anatomical Basis of Clinical Practice, 42nd edition","source":"Elsevier","kind":"book","url":"https://shop.elsevier.com/books/grays-anatomy/standring/978-0-7020-7705-0"},{"id":"neumann2016","authors":"Neumann DA","year":2016,"title":"Kinesiology of the Musculoskeletal System: Foundations for Rehabilitation, 3rd edition","source":"Elsevier","kind":"book","url":"https://shop.elsevier.com/books/kinesiology-of-the-musculoskeletal-system/neumann/978-0-323-28753-1"}],"review":{"publishedAt":"2026-08-02","reviewedAt":"2026-08-02","reviewDueAt":"2027-08-02","evidenceLevel":"established"},"limitations":["The muscle and the band are extracted together in the scene: the boundary between the fleshy belly and the fibrous band is not drawn, although it is sharp.","The fascia lata, of which the band is the lateral thickening, wraps the whole thigh: only its lateral part is represented.","Iliotibial band syndrome is a clinical subject with debated mechanisms. This page describes an anatomy and establishes neither its causes nor what to do about it."],"seo":{"title":"Tensor fasciae latae — a muscle that pulls on a band, not a bone","description":"Iliac origin, insertion on the iliotibial band, transmission down to the tibia, and its role in sideways control of the pelvis and knee.","canonicalPath":"/en/body/muscles/tensor-fasciae-latae","image":"/og/en/anatomy-tensor-fasciae-latae.png"},"app":{"offlineEligible":true},"version":1}