Why do we humans have so much trouble with our backs? Well, what makes a human a human? What can we say that, “without this, this organism would be something else.” Going backward in time toward the apes we get more primitive and less human. If it’s more ape than human, it’s called a pongid (a Congolese word for ape). If it’s more human than ape, it’s called a hominid. The one big difference is that hominids (humans) are bipedal – we habitually and comfortably walk on two legs. For walking, a lordotic curve in the lumbar spine, (the “backward” curve at the “small” of our back) enables us to balance on two legs. Although other animals can walk on two legs, only humans have a lordotic curve.
Birds are bipeds, as are ostriches and penguins. None of them have a lumbar lordosis. Bird and ostrich legs are more centered for balance and penguins prefer to swim or slide on their belly. Kangaroos and dinosaurs are bipedal, but have no lumbar lordosis. They need long tails for balance. Bears and chimps can walk on hind legs, but not well or comfortably. So we can say that a human is a tail-less, habitual and comfortable biped made possible by a lumbar (and cervical) lordotic spinal curve.
When we’re upright the lumbar spine supports most of our body weight and the neck supports a large head. No wonder that these are areas of damage to the intervertebral discs in the spine. And the majority of disc problems are in the lower two discs of both the cervical and lumbar spine, where the most stress occurs. When a disc begins to protrude it stretches its capsule, which contains nerves, causing local pain, muscle spasm and stiffness – a reflex attempt to “splint” the spine and reduce the pain. Further protrusion of that disc may displace or compress a spinal nerve, causing pain in the associated extremity. With enough pressure, the nerve may begin to lose function, manifest by numbness, weakness or reflex changes.
So the price we pay for walking is a high incidence of back pain. But walking frees up our arms and hands to grasp, examine and manipulate things and that has helped develop the brains that we have used to figure this all out.
How can we avoid back trouble? I’ll discuss this next. Stay with me.