Superior (Cranial) / Inferior (Caudal)
Superior structures are closer to the head while inferior structures are closer to the feet. In the Visible Human at right, the lungs are superior to the diaphragm while the liver is inferior to the diaphragm.
Anterior (Ventral) / Posterior (Dorsal)
Anterior structures are closer to the front of the body while posterior structures are closer to the back. In the Visible Human, the sternum is anterior to the heart while the vertebrae are posterior to the heart.
Medial / Lateral
Medial structures are closer to the midline while lateral structures are further from the midline. The Visible Human illustrates the masseter lateral to the ramus of the mandible and the medial pterygoid muscle medial to the ramus of the mandible.
Proximal / Distal
Proximal and distal are terms of relationship referring to relative position along the longitudinal axes of the extremities. The
humerus is proximal to the radius while the scaphoid is distal to the radius.
Proximal and distal are also used to relate position along peripheral nerves or blood vessels branching away from the spinal cord (or brain) or heart. Concerning branches of the axillary artery, the
thoracoacromial artery is a proximal branch and the posterior humeral circumflex artery is a distal branch.
Superficial / Deep
Superficial structures are closer to the surface while deeper structures are closer to the center (midpoint) of the body or extremity. The pectoralis major is superficial to the pectoralis minor, while the axillary artery is deep to the pectoralis minor.