Curvature of the Spine
Curvature of the spine is required knowledge for some first-level courses in anatomy & physiology and related health science subjects. This page includes a summary of study information about curvature of the spine.
In the context of human biology (or human anatomy & physiology) the spine is another word for the vertebral column (assuming that the word 'spine' is used on its own as opposed to in reference to specific features on bones, e.g. the spine of scapula).
Curvature of the Spine in Adults
The shape of a normal adult human spine is shown in the diagram opposite. This labels the 4 curves of the vertebral column:
- Cervical curve - formed by 7 cervical vertebrae
- Thoracic curve - formed by 12 thoracic vertebrae
- Lumbar curve - formed by 5 lumbar vertebrae
- Sacral curve - formed by 5 sacral vertebrae
This differs from the shape of the spine of a human fetus - which consists of one single curve formed by all 4 of the cervical, thoracic, lumbar and sacral regions that eventually form the 4 curves that form that adult spine.
Postural Deformities
There are 3 main types of postural deformity due to abnormalities in the curvature of the spine. They are:
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Lateral View
of right-side of spine |
Posterior View
spine from behind |
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Compare with 'Normal Spine': |
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This shows a normal (almost elongated 'S-shaped') curvature of spine when viewed from the right-side and a straight (upright) spine when viewed from behind.
Together, these views show that the four curves of the adult human spine are in the midsagittal plane and so can be seen from lateral views of the spine.
When viewed from either the posterior or anterior
direction i.e. from directly behind or directly in front of the person, normal spines appear to be straight.
See, for e.g. an anterior view of a human skeleton. |
1. |
Kyphosis |
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Excessive outward (backwards) curvature
of the spine, causing hunching of the back. |
2. |
Lordosis |
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Inward (forwards) curvature of the spine.
Some lordosis in the lumbar and cervical regions of the spine is normal. Exaggerated lordosis may occur in adolescence - possibly as a result of faulty posture, or due to disease affecting the vertebrae and spinal muscles. |
3. |
Scoliosis |
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Lateral
(sideways) deviation
of the spine.
Scoliosis may be caused
by congenital or acquired
abnormalities of the vertebrae,
muscles, and / or nerves. Treatment may involve
the use of spinal braces
and, in cases of severe
deformity. surgical correction
by fusion or osteotomy. |
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Note: The diagrams shown for 1. - 3. above are simple general cases. There are many more specific possibilities and, therefore, names of the conditions - depending on the precise location and extent of deformation of the spine.
All of the above sketches are simple diagrams that could be drawn quickly in a test or exam.
It is possible to draw these diagrams quickly and clearly by indicating how each of the three conditions of abnormal curvatures of the spine differ from a normal healthy spine. Remember to label the views 'lateral', 'anterior' or 'posterior' and in the case of lateral views to state if you are showing the right-side or left-side of the spine, or (alternatively) 'lateral view from the right' or 'lateral view from the left'.
More specific types of curvature of the spine
The following are examples of more specific names of conditions involving curvature of the spine. The table is divided into three sections so that the corresponding general type of curvature of the spine can be found easily in the diagrams above.
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Kyphosis |
- Postural Kyphosis - most common form of kyphosis. May be attributed to 'slouching' in young patients. In older people it is sometimes called 'Hyperkyphosis' or 'Dowager's Hump'.
- Scheuermann's Kyphosis or Scheuermann's disease - usually affects teenagers and involves more extreme deformity than postural kyphosis.
- Nutritional Kyphosis - due to nutritional deficiencies e.g. of Vitamin D (causing rickets).
- Post-traumatic Kyphosis - resulting from vertebral fractures.
- Congenital Kyphosis - present since before birth e.g. vertebrae may be malformed or fused together in the womb resulting in progressive kyphosis as the child develops. May also appear in later years in combination with other conditions e.g. cerebral palsy.
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Lordosis |
- Cervical Lordosis - inward curve in the upper (cervical) region of the spine, i.e. the neck area.
- Thoracic Lordosis - inward curve in the upper (thoracic) region of the spine.
- Lumbar Lordosis - inward curve in the lower (lumbar) region of the spine.
- Congenital Lordosis - present since before birth.
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Scoliosis |
- Thoracic (Curve) Scoliosis - curve in the upper part of the spine
- Lumbar (Curve) Scoliosis - curve in the lower part of the spine
- Non-structural Scoliosis - (also known as 'Functional Scoliosis' and 'Postural Scoliosis') structurally normal spine that appears to be curved due to another condition e.g. legs different lengths. Mild and changes or disappears when the person bends into certain positions / postures.
- Structural scoliosis - fixed curvature of spine (even when the person changes position).
There are several types of structural scoliosis:
- Idiopathic - of unknown / unidentified cause.
- Neuromuscular - curve due to a condition affecting posterior muscles or nerves e.g. cerebral palsy, neurofibromatosis.
- Osteopathic - due to a bone abnormality.
- Congenital - present since before birth.
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This list is not exhaustive. Some combinations of the above are also possible but in most cases unusual, e.g. congenital thoracic lordosis (as described in a paper by R.B.Winter et.al, 1978: http://www.jbjs.org/data/Journals/JBJS/572/806.pdf)
End of notes about the curvature of the spine. See also how many bones are in the human body, the structure and functions of bones, cranial and facial bones, bones of the feet and hands, skeletal disorders and bone markings.
