The sartorius muscle performs which action?

The sartorius muscle performs which action?

• A. flexes, abducts and laterally rotates thigh at hip
• B. flexes and medially rotates leg at knee joint
• C. extends thigh at hip
• D. adducts and medially rotates thigh

Answer: (A)

Sartorius acts on the hip to flex, abduct, and laterally rotate the thigh. Its path from the anterior iliac spine across the thigh to the medial upper tibia lets it lift the thigh upward (flexion), move it away from the midline (abduction), and twist it outward (external rotation). This combination of actions at the hip is characteristic of sartorius and explains why the option describing flexion with abduction and external rotation of the thigh is correct. Actions at the knee are separate—sartorius can assist knee flexion, but the primary single-joint action described here is about the hip. Other options propose thigh extension or adduction/medial rotation, which are not the primary actions of sartorius. Remember the tailor’s position: hip flexion plus abduction and external rotation sums up what this muscle does at the hip.

Sartorius acts on the hip to flex, abduct, and laterally rotate the thigh. Its path from the anterior iliac spine across the thigh to the medial upper tibia lets it lift the thigh upward (flexion), move it away from the midline (abduction), and twist it outward (external rotation). This combination of actions at the hip is characteristic of sartorius and explains why the option describing flexion with abduction and external rotation of the thigh is correct.

Actions at the knee are separate—sartorius can assist knee flexion, but the primary single-joint action described here is about the hip. Other options propose thigh extension or adduction/medial rotation, which are not the primary actions of sartorius. Remember the tailor’s position: hip flexion plus abduction and external rotation sums up what this muscle does at the hip.