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Lordosis, kyphosis, and scoliosis refer to curvatures of the spine.
Lordosis refers to the normal inward curvatures of the spine at the cervical and lumbar regions,
while kyphosis refers to the normal outward curvature of the spine specifically at the
thoracic region.
These terms get used interchangeably with hyperlordosis and hyperkyphosis, which means
that the curves look abnormally pronounced.
Finally there’s scoliosis which always refers to the abnormal sideways curves of the spine.
Now, the bony spine is made of vertebral bones, and there are intervertebral discs that sit
between adjacent vertebrae.
The spine is made of 33 vertebrae, which can be divided into 5 regions.
The cervical region has 7 vertebrae, the thoracic region has 12 vertebrae, the lumbar region
has 5 vertebrae, the sacral region has 5 vertebrae, and the small tail-like coccygeal region is
made up of 4 fused vertebrae.
Normally, the cervical and the lumbar spines slightly curve inward.
This results from the fact that the intervertebral discs in these two regions are thicker anteriorly
than posteriorly, which causes this part of the spine to lean forward.
On the other hand, the thoracic and the sacral spines are normally curved backward, which
is normal kyphosis.
Lordosis and kyphosis are typically associated with underlying conditions.
For example, in osteoporosis the bones become porous and weak, and can develop compression
fractures causing the bones to collapse a bit.
This can cause a spinal deformity and can also impinge on nearby nerves.
Misaligned vertebrae can also exert too much pressure on the intervertebral discs, causing
them to degenerate.
Other conditions include spondylolisthesis, in which a vertebrae slips out of its normal
position, or conditions like Ehlers-Danlos syndrome and Marfan syndrome, where bones
and connective tissues overgrow, causing spinal instability.
Obesity can also put excess unbalanced weight on the spine causing it to deform.
Other causes include inflammation of the intervertebral discs, which can happen from overuse due to
a sports injury or lifting weights in an inappropriate way.
Lordosis typically affects the lumbar region, and can specifically result from the trunk
flexors and the hip extensors becoming too weak to balance the action of trunk extensors
and hip flexors.
When that happens, the lumbar spine gets over-extended, causing it to progressively curve inwards,
causing lumbar lordosis.
Lordosis results in an incurved back in the cervical or lumbar spine.
Kyphosis mainly affects the thoracic spine.
It usually occurs when the front of the thoracic vertebrae gets deformed or crushed, causing
this part of the spine to excessively bend forward.
Kyphosis typically results in a rounded back in the thoracic spine, which looks like a
hump in the upper back.
There are a few types of kyphosis.
First, there’s postural kyphosis which arises from repeated poor posture - like slouching
for a long time.
Postural kyphosis is most common in young females.
Second, there’s Scheuermann's kyphosis, which is where the vertebrae get structurally
deformed and become wedge-shaped for an unclear reason.
This is often associated with scoliosis, and referred to as kyphoscoliosis.
Lastly, there’s congenital kyphosis, which develops when the vertebrae get deformed during
fetal development, resulting in a baby that’s born with kyphosis.
In general, if kyphosis is severe, it can reducing the space in the thoracic cavity,
which can compress the heart and prevent the lungs from fully expanding.
Finally, there’s scoliosis, which is when the spine becomes twisted or develops a sideways
curve, resembling an “S” or a “C” shape, often resulting in uneven shoulders
and hips.
The majority of the time, the underlying cause is unclear, and it’s thought that it may
be due to a defect in the composition of the intervertebral discs.
These disks have a reduced amount of glycosaminoglycans, which changes their ability to act as shock
absorbers, and causes the spine to get misshapen.
Scoliosis is often seen in individuals with neuromuscular disorders that cause progressive
muscle weakness, like cerebral palsy or muscular dystrophy.
In severe scoliosis, there can be a deformity in the chest cavity, compressing the heart
and the lungs similar to what’s seen in severe kyphosis.
In terms of symptoms, spine deformities can cause mild to severe pain and the stiffened
spine can make it difficult to move.
In severe kyphosis and scoliosis, the small thoracic cavity can lead to shortness of breath
and an inability to exercise.
The diagnosis of lordosis, kyphosis, and scoliosis are done by physical examination of the back.
To figure out the extent the spinal deformity, the Cobb angle can be measured.
That’s the measurement between two lines drawn perpendicular to the upper border of
the uppermost vertebra, and the lower border of the lowest vertebra involved in the curvature.
In addition radiographs can be taken of the back as well.
Treatment of lordosis, kyphosis, and scoliosis typically includes physical exercises to limit
the disease progression and maintain the range of motion, as well as pain medication when
it's needed.
For children and young adolescents, fixing braces can sometimes help prevent further
spinal deformity.
In rare situations, surgery may be needed.
Alright, as a quick recap.
Lordosis and kyphosis are usually secondary to diseases or injuries which deform the vertebrae
and ligaments, such as vertebrae fractures, spondylolisthesis, Ehlers-Danlos syndrome,
and Marfan syndrome.
Scoliosis is linked with some neuromuscular disorders like cerebral palsy or muscular
dystrophy.
In severe cases, lordosis, kyphosis and scoliosis can cause back pain, and kyphosis and scoliosis
may deform the chest resulting in shortness of breath, and cardiac failure.
Treatment usually involves physical exercises, braces and pain medication, and surgery in
severe cases.