Before opening the bursa, locate the end of the oviduct by gently separating the oviduct and ovary. Orient the ovary and oviduct so that the ampulla lies horizontally and the end of the oviduct is facing in the direction of the impending insertion of the transfer pipet. Rotate the mouse on the microscope stage if necessary. Avoid clipping through the bursal blood vessels. Use crocus cloth to smooth the edges and slightly blunt the point of the tweezers.
New tweezers have edges that are sharp enough to cut tissues.
Insert tweezers into the hole in the bursa. Expose the osteum by gently opening the gap between the ovary and the oviduct. This will stabilize the fimbria and ampulla making it easier to insert the transfer pipet. Pick up the transfer pipet in your right hand. Note that in the picture, the ampulla is now rotated downward.