sartorius
noun
sar·to·ri·us sär-ˈtȯr-ē-əs 
plural sartorii sär-ˈtȯr-ē-ˌī
-ē-ˌē
: a muscle that crosses the front of the thigh obliquely, assists in rotating the leg to the cross-legged position in which the knees are spread wide apart, and in humans is the longest muscle
Word History
Etymology
New Latin, from Medieval Latin sartor tailor, from Latin sarcire to mend
First Known Use
1704, in the meaning defined above
Medical Definition
sartorius
noun
sar·to·ri·us sär-ˈtōr-ē-əs
plural sartorii -ē-ˌī
: a muscle that arises from the anterior superior iliac spine, crosses the front of the thigh obliquely to insert on the upper part of the inner surface of the tibia, is the longest muscle in the human body, and acts to flex, abduct, and rotate the thigh laterally at the hip joint and to flex the leg at the knee joint and to rotate it medially in a way that enables one to sit with the heel of one leg on the knee of the opposite leg