Oh, yeah! Check out those nice curves. That's right, those nice spinal curves. This is your spine. From the front, you can see it straight but
from the side, you'll see curves – kind of like an elongated S. These curves are crucial
for maintaining spinal health throughout your life. Think of your spine as a spring alternating
from curve to curve. When you walk or run or twerk, there's contact
with the ground. You're hitting or pushing off it with your
weight and pressure. This creates force which your spine is able
to then disperse. This is necessary for body posture and balance
but also important if you don't want that force impacting your brain. So, the spine or vertebral column is part
of the larger axial skeleton. It houses the spinal cord which is a key structure
of the central nervous system and has thirty-three individual vertebrae – twenty four of which
are separated by intervertebral discs. This allows slight movement of the vertebrae
and act as shock absorbers. Now as you can see, there are four curves
in the spine. You're probably most aware of the lumbar curve,
the thoracic curve and the cervical curve as these are the most frequently referred
to by doctors and physical therapists but there's also the sacral curve way down here. Of these four curves, you can see that both
the cervical and lumbar curves are shaped inwards called lordotic curves while the thoracic
and sacral curves are shaped outwards or kyphotic curves. These can be classified as primary and secondary
curves. But, why the distinction? Well, for primary curves, you've had them
since birth. Not the case for secondary curves, however. These actually developed later on. This means, yes, at one point in your life,
you were missing two curves. You weren't an S. You were a C. So, the primary
curves form during the fetal development. You can see that the C-shape is actually well-suited
to the cramped conditions of the womb. The sacral curve helps to support the abdominal
organs while the thoracic curve which connects or articulates with the rib cage accommodates
and protects your lungs and heart. As an infant when you crawl into the fetal
position, that's indeed the natural position of your spine. You don't yet have the muscle strength to
hold your head up. Now things are about to change cause the next
few months of life sees you interacting with the world around you. It's a curious time – turning in the direction
of noise or light that catches your attention, talking to giant people. This requires the lifting and movement of
the head which in turn leads to the development of a secondary curve in the upper spine – the
cervical spine. This curve is in the opposite direction of
the primary curve. So, it takes a bit for it develop. As you start to creep and crawl, the secondary
curve of the lower spine now starts to form. This is the lumbar curve between the rib cage
and the pelvis. This is the final curve to develop and is
responsible for that arch in the lower back, from a C to an S. As you start to walk, this
all gets strengthened. Now, back to the fully formed spine. You may have noticed the posture of some people
and this could be you, too, to be rather exaggerated whether due to lordotic curves or kyphotic
curves. The successive or abnormal spine curvature
can be caused by poor posture or spinal diseases. With lordosis specifically in the lumbar region,
there can be a swayback appearance. A person may also look like their sticking
their stomachs outs or their butts out. This curvature has been reported more so for
women than for men with it being especially common during pregnancy. Dancers are known to suffer from this, too,
due to the constant strain they put on their backs. Usually for most people, though, these conditions
are the result of poor posture and so are reversible by learning the correct posture
and by doing appropriate exercises. Other names for this include hollow back and
saddle back, named after a similar condition that affects horses. With kyphosis specifically in the thoracic
region, there is a humpback appearance or dowager's hump where a person may look like
their hunching or slouching over. A normal thoracic curve should have a slight
kyphotic angle ranging from twenty to fifty degrees, but if it gets past fifty, you've
gone humpback. This time, the curvature is more frequently
seen in males than in females although there's a marked increase for older women as they're
more likely to suffer from osteoporosis. Other common names for this include roundback
and Kelso's hunchback. In addition to lordosis and kyphosis, there's
also scoliosis which I'm sure you've heard of. It's the lateral or sideways curving of the
spine. This is actually the most common abnormal
curvature occurring in about three percent of the population. It's more common among females. What would happen now if we consider the opposite
condition? What if you had little to no curves in your
spine? What if you're a flatback? Well, the loss of normal lordosis and kyphosis
would be harmful. With such a flat spine, you would have terrible
difficulty even standing up straight. Okay, consider the African apes such as chimpanzees,
gorillas, orangutans – they have an inability to curve their lumbar spines due to only having
three or four lumbar vertebrae as opposed to the five in humans. There's a limited range of motion forcing
them to stoop forward awkwardly as they move and walk. This would be similar for the case of flatback
humans. You'd always have a sensation of falling forward. You'd have chronic back pain with massive
spinal degeneration. Daily activities would be a constant struggle. You'd suffer from extreme fatigue. You'd likely need a cane or walker to assist
you when walking as your weight wouldn’t be centered over your pelvis and legs. Basically, life would suck. So, it's unfortunate then that this is, in
fact, a real condition that some people suffer from albeit to varying degrees. It's called flatback syndrome and can be caused
by disorders such as arthritis and from some certain spinal surgeries. Fortunately, for the majority of us, we have
the strength and flexibility from the normal curves in our spine. If quadrupeds, which are animals with four
limbs or feet, would have our S-curve instead of their normal singular curve, it would be
debilitating for them. Their backs and hips would be in constant
strain. But as humans, this spinal construction affords
a balanced inline structure for our unique upright structure as in where the only creatures
on this planet with such a spine. I guess you can say that when it comes down
to it, us, humans are indeed the curviest animals of all. Thanks for watching. We hope you enjoyed this topic and if you've
ever had problems with your spine – lordosis, kyphosis, scoliosis, flatback, anything – tell
us about it in the comments below. Give this video a thumbs up, share it, and
if you want to learn more about the unique human spine, you can go ahead and check out
the Kenhub website. Alright, guys, I'll see you next time.
