Log in
Anatomy · Anatomical structures

Sartorius muscle

m. sartorius

Sartorius muscle (m. sartorius) is the longest muscle in the human body, belonging to the anterior compartment of the thigh. It runs obliquely downward and medially, connecting the pelvis to the leg, and provides a complex movement of flexion and rotation of the leg, participating in crossing the legs.

Test your knowledge on this topicAsk the AI
GroupAnterior compartment of the thigh
FeatureThe longest muscle in the body
FasciaHas its own isolated fascial sheath from the fascia lata
InnervationFemoral nerve (L2–L3)
3 min readFor medical studentsUpdated 09/24/2026
Material prepared by WhiteCoat Pro editorial team based on platform study guidesReviewed by medical editor: Aulov A. A., general practitioner · 09/24/2026

Origin and insertion

  • Origin (O): originates from the anterior superior iliac spine (spina iliaca anterior superior).
  • Course of fibers: runs obliquely downward and medially, crossing the anterior region of the thigh, and passes anteriorly to the medial surface of the knee joint.
  • Insertion (I): attaches medially to the tibial tuberosity. In this region, its tendon merges with the tendons of the gracilis (m. gracilis) and semitendinosus (m. semitendinosus) muscles, forming a structure known as the pes anserinus (pes anserinus). 2 to 3 subtendinous bursae of the sartorius muscle are often described at the insertion site.

Functions

  • Flexion: flexes the thigh and also flexes the leg at the knee joint.
  • Rotation and abduction: abducts the thigh and rotates it laterally (externally rotates). It rotates the flexed leg inward (medially rotates).
  • Complex movements: due to its functions, the muscle participates in a specific movement — crossing the legs.
Test your knowledge on this topicExercises from the Anatomy course question bank with instant answers and explanations.

Blood supply and innervation

  • Innervation (N): supplied by the femoral nerve — n. femoralis (spinal segments L2–L3).
  • Blood supply: provided by branches of the femoral artery (a. femoralis), the lateral femoral circumflex artery (a. circumflexa femoris lateralis), and the descending genicular artery (a. genus suprema).

Topography and adjacent structures

  • Fascial compartment: the muscle is surrounded by the fascia lata (fascia lata), which forms an isolated sheath for it. The outer surface of the fascia is particularly dense. The sartorius muscle is located medial to the tensor fasciae latae (m. tensor fasciae latae).
  • Relation to the adductor canal: the sartorius muscle acts as the roof of the adductor canal (Hunter's canal, canalis adductorius). The saphenous nerve (n. saphenus) and descending genicular vessels (a. et v. descendens genus) emerge into the fatty tissue directly beneath the sartorius muscle through the anterior opening of the canal in the septum intermusculare vastoadductoria.
  • Subcutaneous layer: subcutaneous tissue is well developed above the fascia in this area, containing the trunks of the great saphenous vein (v. saphena magna). The anterior cutaneous branches of the femoral nerve (rr. cutanei anteriores n. femoralis) penetrate the fascia along the medial margin of the sartorius muscle.
  • On transverse section: in the upper third of the thigh, the muscle is visualized as part of the anterior compartment along with the rectus femoris and vasti muscles.

Clinical significance

  • Surgical landmark: the medial margin of m. sartorius and the superior opening of the adductor canal are used as landmarks for access to the femoral artery (a. femoralis) during bypass surgery.
  • Neurological assessment: to detect paresis in mononeuropathies, the strength of the sartorius muscle is assessed using the MRC (Medical Research Council) scale.
  • Pain syndrome: the bursa (bursa anserina) located near the muscle insertion site is a frequent cause of pain on the medial surface of the knee.
How to memorize

The function of the muscle is easy to remember by its characteristic complex movement — it participates in crossing the legs.

Class and exam questions

What is the pes anserinus and how does the sartorius muscle contribute to it?

The pes anserinus (pes anserinus) is the common insertion site of the tendons of the sartorius, gracilis, and semitendinosus muscles on the medial tibia.

Which wall of the adductor canal is formed by the sartorius muscle?

The sartorius muscle forms the roof of the adductor canal. Beneath it lies the intermuscular fascial partition (lamina vastoadductoria).

Which nerves innervate the sartorius muscle?

The muscle is innervated by branches of the femoral nerve (n. femoralis) from spinal segments L2–L3.

Got questions? Ask AIThe AI tutor has reviewed the material on the "Sartorius muscle" and will explain it in simple terms.

What else to study on this topic

  • Adductor canal (canalis adductorius)
  • Femoral nerve (n. femoralis)
  • Pes anserinus (pes anserinus)
  • Fascia lata of the thigh (fascia lata)

Study the complete topic in the Anatomy course

This is a summary. The course covers everything tested in classes and exams.

  • Complete study guide on "Sartorius muscle" and 1,363 other subject pages
  • Assignments and quizzes after every topic — just like in a colloquium
  • AI tutor answers questions on the topic anytime
  • 295 video lessons by subject
Open full reviewSubject curriculumfrom 599 ₽ per month

Other topics in the "Anatomical Structures" section

Saphenous openingFlexor digitorum brevisFemoral nerveFascia lataAdductor canalSaphenous nerveIliopsoas muscleDeep fibular nerveOblique popliteal ligamentAdductor magnus muscleTibialis posterior muscleSuperficial fibular nerveAdductor longus muscleSemimembranosus muscleGracilis musclePectineus muscleSoleus muscleRectus femoris muscleFibularis longus muscleAdductor hiatusLacunar ligamentAnatomy of the ankle joint
Entire "Anatomical Structures" section

Free video lessons: AnatomyShort lessons with study notes — no registration required.

Watch lessons

Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.