Assertion: acetabulum | /r/Causes | friction
Facets:
value: within the joint
type: LOCATION
Source sentences:
text: In many hips, the head of the femur (ball) and the acetabulum (socket) don't fit together perfectly, causing abnormal contact and friction in the joint.
text: Secondly, the caput or acetabulum are not smooth and round, but are misshapen, causing abnormal wear and tear or friction within the joint as it moves.