Sartorius
The sartorius is the longest muscle in the human body, running diagonally across the anterior thigh. Its name means 'tailor' because it produces the cross-legged sitting position used by tailors. It is a hip flexor and knee flexor.
Origin, Insertion, Action, Innervation
OOrigin
Anterior superior iliac spine (ASIS)
IInsertion
Upper medial surface of tibia (pes anserinus)
AAction
- • Flexion of the hip
- • Abduction of the hip
- • Lateral rotation of the hip
- • Flexion of the knee
- • Medial rotation of the flexed knee
NInnervation
Femoral nerve (L2, L3)
Blood Supply
Femoral artery via muscular branches
Clinical Relevance
The sartorius forms part of the pes anserinus with gracilis and semitendinosus tendons. Pes anserinus bursitis causes pain on the medial knee. The sartorius helps define the femoral triangle border.
Palpation
Palpate on the anterior thigh running from ASIS toward the medial knee. It is superficial but may be difficult to distinguish from surrounding muscles.
Study Tips
- ✓Longest muscle in the body
- ✓ASIS to pes anserinus (medial tibia)
- ✓Pes anserinus = Sartorius, Gracilis, Semitendinosus ('Say Grace before Tea')
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Common questions about the sartorius
The name sartorius comes from the Latin word 'sartor' meaning tailor. The muscle produces the cross-legged sitting position traditionally used by tailors when sewing: hip flexion, abduction, and lateral rotation.
The pes anserinus ('goose foot') is where three tendons insert together on the upper medial tibia: sartorius, gracilis, and semitendinosus. A bursa beneath these tendons can become inflamed (pes anserinus bursitis).
Yes, the sartorius is the longest muscle in the human body, running from the ASIS to the medial tibia, crossing both the hip and knee joints. However, it is relatively thin and not particularly powerful.
The sartorius is innervated by the femoral nerve, carrying fibers from the L2 and L3 nerve roots. The femoral nerve also innervates the quadriceps and iliacus muscles.