Infinite

The body is intricate.

Worth pondering.

The systemic similarity within all humanity, for many years.

The articulations

The nerves

The vascular system

The lymphatics

The endocrine

Etc…..

Very similar -- yet so different.   

Morphologies skeletal, neural, fascial, endocrine the symmetry and asymmetries

Tissue variations the mixtures of elastin and collagen, responses to: stimulus, inflammation, auto-immune. The genetic coding problems of numerous quantity.

Marfans, Upper Motor Neuron, Haemophelia, Adrenocortical Carcinoma …. A few that jump to mind while browsing this list.

Etiology; genetic, sclerotic, post traumatic, physically worn down, or unknown origin.

The DIFFERENCEs

Vast - broad - incredible - unbelievable - unfair - monumental - bewildering - excructiating - wonderful....

Variations on the same

Think of what you have asked your body to do for you: 

How often.   

Which time period. 

What have you ingested.  

Locations of corner cutting

Locations of great care. 

What makes your system feel good. 

What makes it feel horrible. 

What stresses it. Positively and Negatively. 

The amount of difference within all these combinations, within the population.

Infinite.