Anatomy And Function: Location and Movement

"Our prime purpose in this life is to help others. And if you can't help them, at least don't hurt them." Dalai Lama. (almost as if he had today's strength and conditioning coaches in mind. 

by Dr. Ken E. Leistner

Referring to Part One of this series, at all times recall that reference to the body anatomically, is made with the body in the accepted ANATOMICAL POSITION: erect with palms facing forward. The terms discussed with parts in relation to each other's position, such as superior, inferior, external, superficial, distal, and proximal should at this point, be clear. A good study aid is a model or drawing of the human figure, with time taken to relate body parts to one another based upon their position.

There are a few terms that are unique to the limbs. While location of parts is often made relative to the midline of the body, within the limbs, it is the habit of anatomists to make descriptions relative to the paired bones. In the upper extremity, there are radius and ulna bones in the forearm with the radius being the lateral of the two bones. The term RADIAL refers to the thumb or lateral side of the extremity while ULNA refer to the pinky or medial side. In the leg, the tibia resides towards the midline of the body or medial to the fibula. Thus, reference is made to the TIBIAL or big toe side and FIBULAR to a part toward the little toe side. The anterior surface of the hand, the part facing the viewer when the body is in the anatomical position, is the PALMAR SURFACE while similar ref­erence is made in the foot; the PLANTAR SURFACE is the sole of the foot. The opposite surface of both the hand and foot is the DORSUM or dorsal surface.

Description of movement of the different parts of the body are part of the lexicon. Unfortunately, some joint movements are complicated, or a combination of movements and have their own terminology but there are general (terms that are applicable and allow a very clear understanding of a part's function. FLEXJON is the ventral bending of a joint. While it usually refers to "bending" at a joint, because some joints can be "bent" in two directions, the distinction must be made. It is a decrease in the joint angle. It is best to think of flexion as bending towards the original ventral sur­face. If flexion occurs beyond the straight or anatomi­cal position, it can be referred to as HYPERFLEXION. EXTENSION is the opposite of flexion. It is best thought of as a straightening of a part or an increase in the joint angle. It is also a movement or straightening to­wards the original dorsal surface. If extension occurs beyond the straight or anatomical position, it can be referred to as HYPEREXTENSION. Some of the excep­tions, or special cases immediately come to mind how­ever, as the movement of the foot and hand have their own terminology. If one moves the foot into ventral flexion, it is called DORSIFLEXION of the foot. Exten­sion of the foot is called PLANTAR FLEXION, the word flexion utilized even though it results in an increase in the joint angle and a straightening of the limb. Turn­ing the sole of the foot inward is termed INVERSION, outward, EVERSION. With the hand, turning the palm downward while the forearm is in the horizontal posi­tion is termed PRONATION; turning it upward is termed SUPINATION.

ABDUCTION means to move away from the mid­line of the body. Abduction of the fingers is to move them apart, as abduction also means to separate. AD­DUCTION means to move towards the midline of the body. ROTATION of a part means to have movement around its long axis. If this occurs in a way that the anterior surface turns laterally or to the outside, it is termed LATERAL or EXTERNAL ROTATION. If the anterior surface turns medially or it is termed ME­DIAL or INTERNAL ROTATION. CIRCUMDUCTION is one of the compound or combination movements men­tioned previously. The movement describes a cone with the distal part moving in a circle and the proximal or near part, serving as a pivot point. It is actually a com­bination of flexion, abduction, extension, and adduc­tion.

Once location, direction, and movement of a body part are known, it is rather easy to determine what resistance exercise will provide benefit for a specific muscle. As the interested trainee or strength training professional will utilize these terms and need this knowledge on a daily basis, it is advised that some time be spent insuring that the terms related to proper anatomic description and movement are learned and then used in daily speech and writing.