Assertion: human's feature | /r/HasProperty | groove
Facets:
value: for a muscle
type: PURPOSE
value: according to its discoverers
type: OTHER
value: on the bone
type: LOCATION
Source sentences:
text: According to its discoverers, features of the thighbone implying bipedalism include its overall proportions, the internal structure of the femoral neck (the column joining the ball-shaped head of the femur to the shaft of the bone), and a groove on the bone for a muscle used in upright walking (the obturator externus).