At first glance one side of the human body looks to be the perfect mirror image of the other, but there are subtle differences. The technical term used to describe these ‘differences’ is ‘fluctuating asymmetry’ or ‘near symmetry’.
Symmetry on the Outside
In Leonardo Davinci’s famous drawing of ‘The Vitruvian Man’ (also know as the ‘Proportions of Man’) we see one side of the drawing is the mirror image of the other. In ‘real’humans, ears, eyes, wrists, breasts, gaps between toes, curves of fingers are all slightly different shapes and sizes across the midline.
Symmetry & the Skeleton
The bones of the human skeleton give the body its overall symmetrical shape. That said, the arm and leg bones are not quite symmetrical across the body. Each set of bones tend to be heavier and of slightly different lengths to the other.
Interesting Fact – The hyoid bone is definitely asymmetrical. Feel free to research it as we bet you didn’t know you had one 🙂
Symmetry & the Muscles
The muscles of the body are arranged symmetrically, but being left or right handed influences the development and size of some muscles. For example, if you are left handed, your left bicep will tend to be bigger since you use it more than the one on the right.
Symmetry & the Internal Organs
Most of a human’s internal organs are asymmetrical, that is, they have no symmetry of shape or position.
The heart, spleen & stomach are not symmetrical in shape and lay towards the left side of the body. The gall bladder and most of the liver are found on the right side of the body and are also not symmetrical in shape.
Humans have two lungs but one is smaller than the other. Humans also have two kidneys and, while they are symmetrical in shape, the right one is smaller and slightly lower than the left.