proximal
The midline is just an immaginary line that is drawn down the middle of the object. Often when we use midline we are referring to the body as a whole, so the midline starts at your head and goes down the center of your body towards your toes. So it would go between your eyes, down your nose, and cross your belly button. But in general midline just means an imaginary line cut down the middle of the object.
Medial means situated in the center.
Deep is the medical term meaning far from the surface.
Anterior is a term meaning situated at or toward the front. Frontal may also be used.
Proximal meams towards the origin of a struction. For instane, the elbow is proximal to the wrist.
Inception or onset means beginning in medical terms.
Extracorporeal
Myoanatomy is the medical term meaning structure of a muscle. It may also mean the study of muscle structure.
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.
osteogenesis is the beginning of bone.
Subtracheal means beneath the trachea.
Contracture is the medical term meaning constriction of tissue.
Oncoanatomy is the medical term meaning study of the form and structure of neoplasms or tumors. It is a branch of gross anatomy.