פירוש על עבודה זרה 49:16

The same three amoraim argue here over the meaning of the verse in which a cook gives a thigh of an animal that “that which was upon it” to Saul.
The “waving” here has to do with a sacrifice that has to be waved, the thigh and the breast together.
The “cap” seems to be the hip bone, or something in that area.