Anatomical planes are used to describe cuts made through a cadaver in order to view structures exposed by the cuts. While a very large number of possible cuts could be made through a particular cadaver, three orthogonal (at right angles to one another) planes are most important. (Limbs are usually cut (transected) in only one plane, perpendicular to their long axis.)
A Dorsal Plane is parallel to the back [for: head, neck, trunk, tail].
A Transverse Plane is perpendicular to the long axis of the body [head, neck, trunk, tail].
A Sagittal Plane divides the body into right/left parts [head, neck, trunk, tail].
The Median Plane is a mid-sagittal plane that divides the body into left/right halves [head, neck, trunk, tail].
Limbs are generally cut by planes that are approximately transverse, relative to the long axis of the limb.