The anatomical term meaning "situated toward the front" is: anterior.
Anterior is a term meaning situated at or toward the front. Frontal may also be used.
Medial means situated in the center.
posterior
Anterior is the medical term meaning front or in front of.
Deep is the medical term meaning far from the surface.
extracorporeal
Extracorporeal
The medical term you are looking for is "posterior." This term refers to the back side of the body or something positioned behind a particular structure.
medial
Subtracheal means beneath the trachea.
Posteroanterior means from back to front.