Question

Brinley crosses her leg while she sits. To cross her leg, she flexes the lower leg and thigh, and then medially rotates her lower leg, which causes a lateral rotation of the hip. Which of the following muscles primarily performs this motion?

A) Semimembranosus
B) Sartorius
C) Semitendinosus
D) Biceps femoris

Answer 1

The sartorius muscle is responsible for the action of crossing one's legs, as it laterally rotates the hip and flexes the leg at the knee.

Step-by-step explanation:

The muscle that primarily allows Brinley to cross her legs while sitting is the sartorius. This muscle is located in the anterior compartment of the thigh and is responsible for flexing, abducting, and laterally rotating the hip, as well as flexing the leg at the knee. When Brinley medially rotates her lower leg to cross it over the other, the sartorius muscle is at play. The sartorius is therefore the correct answer that enables one to sit cross-legged, compared to the other options listed which are primarily muscles of the hamstrings group that flex the knee.