You have four limbs – two arms, two legs – mobilised by some of the largest muscles in the body, and connected to the spinal cord and the brain by a wondrous and complex system of nerves. You can, as a result, walk, bend, drive an automobile, catch a bus or train, climb stairs, write, turn the pages of this book, brush your teeth. You can, if you so wish, rise up from where you are now seated and walk to the kitchen for a snack, into the garden for a stroll, over to the neighbours for a visit.
There is virtually no physical activity or task in your day-to-day existence which does not involve your hands and fingers, your arms, your feet, or your legs and knees.
Consider, for a moment, what life would be like if you didn’t have the use of these. Freedom of movement would cease.