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By Ground Up Strength
Directional terms are widespread in all references concerning human performance, including anatomy, kinesiology, sports medicine, athletic training; and strength and bodybuilding coaching. At first, these terms can be confusing to the student of strength training but they are easy to understand once the fundamentals are studied.
Why would you want to know these terms? Well, lets say you have injured your knee and are having pain on the "outside" part of the joint. To find out what kind of injury you may have suffered, you search for references for "pain on the outside of the knee." However, you find many different directional terms besides outside and inside. In fact, scholarly references may not use these terms at all. The correct terminology is lateral and medial. So which part of your knee has pain? That is where understanding anatomical direction terms comes in handy.
The first important thing to know is the reference position of the body that these terms are derived from. When you are standing straight with your feet pointing forward and together and your hands naturally at your sides, palms facing in, you are standing in the fundamental position. However, anatomists and kinesiologists do not use the fundamental position as a reference. They use the anatomic position. This position is exactly the same as the fundamental position except for one key difference: the palms or the hands are facing forward. The importance of this will become apparent later.
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The image below is a diagram of a human figure in the anatomic position. The labeled directional arrows are meant to give an idea of the fundamental direction terms.
Anatomic Directions
Take special note of the midline. The terms lateral and medial are used in relation to an imaginary line drawn vertically down the center of the body. This midline is also referred to the median or midsagittal plane.
The midsagittal plane is the plane of symmetry of the body, and divides it into equal left and right halves. As stated above this is synonymous with the median plane of the body. As you might find references to the sagittal plane a bit of extra explanation is required. In the figure below, the midsagittal or median plane is shown.
Alternative Names for the Midsagittal Plane
- Sagittal plane
- Median plane
- Anteroposterior plane
- XY plane (based on right-hand coordinate system)
Midsagittal Plane
Image by Edoarado via wikimedia commons
Technically, a sagittal plane is any plane that divides a symmetrical body into left and right halves. This plane, passing down through the body would be parallel to the sagittal suture of the skull, but not necessarily intersecting it. This type of plane could also be called an anteroposterior plane. Sometimes the term sagittal plane is used to refer to the median or midsagittal plane, but it is more conventional to refer to any plane parallel to the median plane, dividing the body into unequal left and right halves, as a parasagittal plane.
The median or midsagittal plane passes through the sagittal suture. When you perform a situp, bend over to touch your toes, do biceps curls, knee extensions or leg curls, you are performing work in this plane.
Anything away from this midline is lateral and anything toward this midline is medial. The tip of your nose is in the median line and your cheeks are lateral to your nose. Now, consider the position of the hands. Which part of the wrist is the medial part? That's right, its the part that is against the body in the anatomic position, or closest to the midline. Now look at the knees. Remember that hypothetical pain on the "outside" part of the knee? Well the outside part of the knee is the part away form the midline. So we are talking about the lateral knee.
Sometimes the terms inside and outside are used when referring to the wrist and the knee, as we have seen. Although these terms are used in this article to mean the same thing as the medial and lateral aspects of these joints, it is best to avoid these terms as different people will mean different aspects when using them. For some, for example, the "inside" of the wrist is the part that corresponds to the palm of the hand, while for others it is the side that is medial, as used here.
Chart of Anatomical Direction Terms, Definitions, and Examples
| Direction Term | Definition | Example |
|---|---|---|
| Anterior | Toward the front of the body or in front of another structure | The pectoralis major is anterior to the scapula, the quadriceps is on the anterior part of the thigh and anterior to the femur |
| Anteroinferior | Toward the front/in front of and below | The kneecap (patella) is anteroinferior to the femur |
| Anterolateral | In front and to the side (outside), away from the midline | The sternocleidomastoid is in the anterolateral region of the neck |
| Anteromedial | In front and toward the midline | The vastus medialis muscle is in the anteromedial region of the thigh |
| Anterosuperior | In front and above, toward the head | The kneecap (patella) is anterosuperior to the tibia |
| Bilateral | On both sides of the body, relative to the midline. | The ears are bilateral. |
| Caudal | Toward the tailbone but sometimes used to mean the same thing as inferior, or toward the feet1 | See inferior. The lumbar spine is the caudal spine. |
| Cephalic | Above another structure, superior, toward the head, pertaining to the head | See superior. The cervical spine is the cephalic spine. |
| Contralateral | Pertaining to the opposite side | The side of the brain that controls the right hand is contralateral to that hand. |
| Deep | Away from the surface of the body, further away from the surface than another structure | The bones are deep to the skin. The splenius cervicus muscle is deep to the upper trapezius. |
| Distal | Away from the midline or trunk. Away from the point of origin. | The hand is distal to the elbow. The elbow is distal to the shoulder. |
| Dorsal | Relating to the back, posterior. Useful in humans when pertaining to the hands and feet. Part of the name of the latissumus dorsi. | The side of the hand opposite the palm, or volar aspect, is the dorsal aspect of the hand. The interossei muscles are dorsal muscles of the hand. |
| Inferior | Below another structure, toward the feet | The knee is inferior to the thigh. |
| Ipsilateral | On the same side | When the splenius muscles contract on one side, ipsilateral rotation and lateral flexion of the neck occurs. |
| Lateral | To the side or on the side, away from the midline (median or midsagital plane) | The illotibial band is on the lateral portion of the thigh. |
| Medial | Relating to the middle or midline. Nearer to the midsagittal or median plane. | The rectus abdominis is medial to the external oblique. The inside of the wrist is the medial aspect of the wrist, corresponding to the ulna bone of the forearm. |
| Posterior | Behind, toward the back, to the rear in relation to another structure. | The gluteus maximus is on the posterior part of the body. |
| Posteroinferior | Behind and below, below and behind another structure. | the soleus muscle is on the posteroinferior part of the leg. |
| Posterolateral | Behind and to the side, away from the midline (outside). | The levator scapulae muscle is on the posterolateral part of the neck. |
| Posteromedial | Behind and toward the midline (to the inside). | The semitendinosus muscle is in the posterormedial part of the thigh. |
| Posterosuperior | Behind and above, toward the head. | The Achilles tendon is posterosuperior to the ankle. |
| Proximal | Closer to the midline or trunk. Closer to the point of origin. | The elbow is proximal to the wrist. The wrist is proximal to the fingers. The word central is also related. |
| Superficial | Nearer to the surface of the body, in relation to another structure. | The trapezius is a superficial muscle of the back. |
| Superior | Above another structure, toward the head, cephalic. | The clavicle is superior to the sternum. |
| Ventral | Relating to the belly or the abdomen, the opposite of dorsal when referring to the body. | The chest, abdomen, and quadriceps of the thigh are all ventral. |
| Volar | Relating to the palm of the hand or sole of the foot. The opposite of dorsal when referring to the hands and feet. Also the term palmar is sometimes used, corresponding with the palm of the hand, and plantar is used for the sole of the foot. | The thenar eminence is on the volar aspect of the hand. |
Anatomical Directions Also Refer to Motions
Although most of the examples given here are of structures and their position relative the anatomical position and to another structure, these directional terms also refer to motion that occurs relative to the anatomical position and to the median plane, or other planes, of the body.
However, the actual movements of joints have their own terms, also relative to the planes and anatomical position. Therefore, although you can move your wrist medially, this motion is usually referred to as adduction of the wrist. Adduction of the wrist is also called ulnar deviation or ulnar flexion, so as you can surmise, joint motions are just as confusing as muscle names, and perhaps more so. Therefore, the various terms of joint motion are beyond the scope of this reference.
Search for Other Terms and Definitions in Our Glossary
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This page created 11 Nov 2011 17:14
Last updated 12 Dec 2011 20:02
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