Human Anatomy : Part 1 : Basic Location Terminology

Whether we realize it or not, our body is the most precious resource of all we've got here around us. Studying the nature of our body and it's composition is not limited to shaping careers of medical aspirants, nevertheless it also delivers insight on proper functioning of our body and helps better understand potential threats in the environment. No, you need not be a doctor to know the basics. Let's start with fundamentals of human anatomy and see how well you find yourself grasping the things.

Fundamental Location Terms

First and foremost we need to address some basic terms related to our body's anatomy. You can consider them as jargon used to indicate the position of a body part, a muscle group, a bone ,an organ within our body or even smaller structures within an organ. 

Let's start with defining the reference cross-sectional planes that form the base of indicating locations in anatomy. Consider a man standing in an anatomical neutral position i.e. upright stance, legs parallel with knees facing forward, toes pointing forwards and arms by the side with palms facing forwards. Have a look at the comparative (Anatomical position vs Fundamental position) pictorial illustration shown above.

1. Frontal/Coronal Plane : Vertical plane perpendicular to the cerebral axis. It divides the body into two parts namely Anterior(front Side) and Posterior(back side).
2. Sagittal Plane : Vertical plane parallel to the cerebral axis. It divides the body into two parts namely Sinister(left) and Dexter(right)
3. Horizontal/Transverse Plane : Horizontal plane parallel to the floor. It divides the body into two parts namely Superior(towards head) and Inferior(towards tail/legs)

Having discussed the reference planes of anatomy, lets move on to the basic location terms that take help of these planes to address a location on the human body. 

1. Superior : Towards the head/ Above another part. The deltoid muscles are superior to the forearm muscles.
2. Inferior : Towards the legs/ Below another part. The forearm muscles are inferior to the deltoid muscles.
3. Rostral/Cranial : Towards the head
4. Caudal : Towards the tail/legs (coccyx)
5. Anterior : Towards the front
6. Posterior : Towards the back
7. Ventral : Towards the front
8. Dorsal : Towards the back
9. Medial : Towards the mid line
10. Lateral : Farther from the mid line
11. Proximal : Closer to the point of origin
12. Distal : Farther from the point of origin
13. Ipsilateral : On the same side of the body. Right leg is ipsilateral to the right arm.
14. Contralateral : On the opposite sides of the body. Right leg is contralateral to the left arm. 

After going through the terminology you would notice similarity between a few terms. Superior & Rostral; Inferior & Caudal; Anterior & Ventral; Posterior & Dorsal. Why do we need multiple terms to convey the same meaning? 

This isn't as simple as it looks but luckily it doesn't take an Einstein to figure out the reason. To understand this better let's look at the human body from a side view.   

As shown in the picture above, there is a 90 degree anticlockwise rotation in the arrows pointing rostral, caudal, ventral and dorsal  directions as we approach the mid section of the brain proceeding from the spine. It should be noted that the terms superior, inferior, anterior and posterior still hold their meanings correct in any case. This is how we could depict the concept through another diagram.

You can assume Dorsal to be the outer/ back side and Ventral to be the inner side. When talking about the head, the scalp would be considered Dorsal and the chin would be ventral. Similarly in the case of the palm of your hand, the inner surface would be Ventral and the outer/back of the palm would be Dorsal. This can be understood better from the pictures we've  put for illustration.

Can you now guess the anatomical locations of the following muscle groups by their names?

• Serratus Anterior
• Latissimus Dorsi (Dorsal)
• Vastus Medialis  (Medial)
• Vastus Lateralis (Lateral)

Try looking into the pictures to make your understanding more vivid. 

This post discusses the basic location terms that you need to know to point out which part of your body you are talking about in an oral conversation. Next, in another part of the Anatomy series we shall cover basic concepts related to bodily movements and posture.