'Knees' in the Bible

And she said, Behold, my maid Bilhah, go in unto her; that she may bear upon my knees, and I also may obtain children by her.

And Joseph brought them out from between his knees; and he bowed himself with his face to the earth.

And Joseph saw Ephraim's children of the third generation: the children also of Machir the son of Manasseh were born upon Joseph's knees.