'Knees' in the Bible

She said, "Behold, my maid Bilhah. Go in to her, that she may bear on my knees, and I also may obtain children by her."

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

Joseph saw Ephraim's children to the third generation. The children also of Machir, the son of Manasseh, were born on Joseph's knees.