From a developmental (embryonic) perspective, we all start with a C-shaped vertebral column that may be referred to as a 'primary curvature', the base reference for subsequent developmental changes. As a neonate starts lifting its head, a 'secondary', cervical curvature begins to develop while the thoracic remains as a 'primary'. As the infant begins to crawl, then walk and assumes an upright posture, the lumbar (another 'secondary') curvature forms while the sacral remains in its primary configuration. I hope this helps to understand the underlying normal as well as abnormal curvatures that one may encounter.
Cervical curve firat to develop as babby tries to lift head.On standing luber curve develops. Thoracic and sacral curves are reactionary in response to these curves.
there are 2 curves primary curve (at birth) and secondary curve . At first all babies born with convex backward vertebral column and this is called primary curve. when the baby starts to straighten its head so the load make a change in the curvature making it concave backwards. later on when the baby starts to straighten the back the load make a change in the lumbar vertebra so change it to concave backwards. therefore adult vertebral column has 2 primary curves (thoracic vertebrae and scrum) and 2 secondary curves (cervical and lumbar)
The adult vertebral column presents four anteroposterior curvatures: thoracic and sacral, both concave anteriorly, and cervical and lumbar, both concave posteriorly . The thoracic and sacral curvatures, termed primary, appear during the embryonic period proper, whereas the cervical and lumbar curvatures, termed secondary, appear later (although before birth) and are accentuated in infancy by support of the head and by the adoption of an upright posture.
4 curves: cervical (curves inwards), thoracic (curves outwards), lumbar (inwards) and sacral (outwards).
Normal curvature is Ok, but some abnormilities in curvatures can cause clinical problems such as Lordosis,Scoloiosis and Kyphosis, especially respiratory and cardiac problems.
Abnormal curvatures are associated with vertebral abnormalities such as fused vertebrae, block, hemivertebra.
Iam Prof. Dr. Muhammad Sharif Khan, have taught zoology in Talimul Islam College, Rabwah, Pakistan for 40 years, retiring in 1999.
I am reporting an abnormality which i encountered while demonstrating arterial systen in Saara hardwickii to BSc class i found an interesting abnormality in the configuration of systemic arch. normally the systermic arches on both sides converge around heart, join each other and form dorsal aorta, running along vertebral column bifurcating near pelvic girdle, in left and right femoral arteries supplying legs.
in the individual what had happened the left arch was short, as has entered vertebral column, and the dorsal aorta was formed by right aortic arch only !
i reported this interesting abnormality in Pakistan journal of science, full reference is below:
Khan, M. S. 1971. An interesting abnormality in the arterial system of Uromastyx hardwickii Grey [sic] and its possible evolutionary significance. Pak. J. Sci., 23(1-2):78-80.
Presents four anteroposterior curvatures thoracic and sacral, both concave anteriorly, and cervical and lumbar, both concave posteriorly
Nice answers guys..., can we add some applied aspect of these curves
abnormal curvatures like (posterior dorsal curvature) khyposis, (anterior curvature) , (Lateral curvature) Lordosis, Scoliosis---
Common issues concerning spinal curvature that are often overlooked are postural-mediated maladies, especially forward placement of the head and accentuated kyphosis of the thoracic vertebral curvature often afflicting those with desk jobs, or other jobs that require one to be seated and/or work with computers for long periods of time. Fortunately, unlike some pathology that promotes such irregular curvatures, these issues can be remedied to some degree by reconditioning of posture
From a developmental (embryonic) perspective, we all start with a C-shaped vertebral column that may be referred to as a 'primary curvature', the base reference for subsequent developmental changes. As a neonate starts lifting its head, a 'secondary', cervical curvature begins to develop while the thoracic remains as a 'primary'. As the infant begins to crawl, then walk and assumes an upright posture, the lumbar (another 'secondary') curvature forms while the sacral remains in its primary configuration. I hope this helps to understand the underlying normal as well as abnormal curvatures that one may encounter.
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