The Mouth Jack
A speculum is a device that holds open a body cavity. The type used in equine dentistry varies.
A full mouth speculum places two metal plates between the nipper teeth and a lever is used to hold open the mouth against hinges of the device located on either side of the cheek. I have one horse in my practice whose lower jaw was fractured by the prolonged use of this type of speculum by another equine dentist.
Another type is the wedge speculum. This style places a solid object (metal or rubber) between the cheek teeth on one side of the mouth. These can be difficult to leave in place and some styles can cause tooth fractures.
The Hand And Arm Is A Speculum By Definition
The use of my hand and arm as a speculum for some reason is not looked upon by other dentist as a valid speculum. Here I give the reasons for why I find it to be perfect.