Medical science have divided our spine surrounded by different parts and name it as coccyx, sacral, lumbar, etc?
Why is it done so? and what are the significance of the different parts , its functions . Try to give factual and scientific responses , lacking asking me to go to specific website making me wait for right answer. Thanks
Answers:
They are divided because of the different functions and characteristics. The coccyx are fused together, but do not make a significant contribution to the pelvis. The sacral vertebrae are fused and connect the hip bones to respectively other. The lumbar vertebrae have very large bodies to support the shipment on them. The thoracic vertebrae have additional parts (processes) to them for the connection of ribs, which demonstrably protect our chest cavities. The cervical vertebrae have different characteristics as well, near the back processes split and holes (foramen) on the side processes for a large artery to run up to the brain. Each segment has different motion characteristics too-you can move the cervical and lumbar spine profusely more than you can move the thoracic area because the ribs restrict a lot of motion. Each section of the spine looks different and you can be tested on what cog of the spine a vertebrae comes from just by looking at the 1 vertebrae so it makes sense that it would have a different signature.
Spinal cord segments
The human spinal cord is divided into 31 different segments. At every segment, right and left pairs of spinal nerves (mixed; sensory and motor) form. 6–8 motor impudence rootlets branch out of right and left ventro lateral sulci in a very orderly demeanour. Nerve rootlets combine to form nerve roots. Likewise sensory nerve rootlets form off right and vanished dorsal lateral sulci and form sensory nerve roots. The ventral (motor) and dorsal (sensory) roots combine to form spinal nerves(mixed; motor and sensory), one on each side of the spinal cord. Spinal nerves, with the exception of C1 and C2 form inside intervertebral foramen (IVF). Note that at respectively spinal segment the border between the central and peripheral nervous system can be observed. Rootlets are a section of the peripheral nervous system.
There are 31 (Some EMS text influence 26, counting the sacral as one solid piece)spinal cord nerve segments in a human spinal cord:
8 cervical segment forming 8 pairs of cervical nerves (C1 spinal nerves exit spinal column between occiput and C1 vertebra; C2 nerves exit between posterior arch of C1 vertebra and lamina of C2 vertebra; C3-C8 spinal nerves through IVF above corresponding cervica vertebra, with the exception of C8 pair which exit via IVF between C7 and T1 vertebra)
12 thoracic segments forming 12 pairs of thoracic nerves (exit spinal column through IVF below corresponding vertebra T1-T12)
5 lumbar segment forming 5 pairs of lumbar nerves (exit spinal column through IVF, below corresponding vertebra L1-L5)
5 (or 1) sacral segments forming 5 pairs of sacral nerves (exit spinal column through IVF, below corresponding vertebra S1-S5)
1 coccygeal segment forming 1 pair of coccygeal nerves (exit spinal column through the sacral hiatus)
Because the vertebral column grows longer than the spinal cord, spinal cord segments do not correspond to vertebral segment in adults, especially in the lower spinal cord. In the fetus, vertebral segments do correspond near spinal cord segments. In the adult, however, the spinal cord ends around the L1/L2 vertebral level, forming a structure certain as the conus medullaris. For example, lumbar and sacral spinal cord segments are found between vertebral levels T9 and L2.
Although the spinal cord cell bodies end around the L1/L2 vertebral even, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from their respective roots to their point of exit from the vertebral column, the nerves of the lower spinal segment form a bundle called the cauda equina.
There are two regions where the spinal cord enlarges:
Cervical enlargement - corresponds roughly to the brachial plexus nerves, which innervate the upper upper limb. It includes spinal cord segments from about C4 to T1. The vertebral levels of the enlargement are roughly alike (C4 to T1).
Lumbosacral enlargement - corresponds to the lumbosacral plexus nerves, which innervate the lower limb. It comprises the spinal cord segments from L2 to S3, and is found about the vertebral level of T9 to T12.
SEE SOURCE Source(s): http://en.wikipedia.org/wiki/Spinal_cord
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Answers:
They are divided because of the different functions and characteristics. The coccyx are fused together, but do not make a significant contribution to the pelvis. The sacral vertebrae are fused and connect the hip bones to respectively other. The lumbar vertebrae have very large bodies to support the shipment on them. The thoracic vertebrae have additional parts (processes) to them for the connection of ribs, which demonstrably protect our chest cavities. The cervical vertebrae have different characteristics as well, near the back processes split and holes (foramen) on the side processes for a large artery to run up to the brain. Each segment has different motion characteristics too-you can move the cervical and lumbar spine profusely more than you can move the thoracic area because the ribs restrict a lot of motion. Each section of the spine looks different and you can be tested on what cog of the spine a vertebrae comes from just by looking at the 1 vertebrae so it makes sense that it would have a different signature.
Spinal cord segments
The human spinal cord is divided into 31 different segments. At every segment, right and left pairs of spinal nerves (mixed; sensory and motor) form. 6–8 motor impudence rootlets branch out of right and left ventro lateral sulci in a very orderly demeanour. Nerve rootlets combine to form nerve roots. Likewise sensory nerve rootlets form off right and vanished dorsal lateral sulci and form sensory nerve roots. The ventral (motor) and dorsal (sensory) roots combine to form spinal nerves(mixed; motor and sensory), one on each side of the spinal cord. Spinal nerves, with the exception of C1 and C2 form inside intervertebral foramen (IVF). Note that at respectively spinal segment the border between the central and peripheral nervous system can be observed. Rootlets are a section of the peripheral nervous system.
There are 31 (Some EMS text influence 26, counting the sacral as one solid piece)spinal cord nerve segments in a human spinal cord:
8 cervical segment forming 8 pairs of cervical nerves (C1 spinal nerves exit spinal column between occiput and C1 vertebra; C2 nerves exit between posterior arch of C1 vertebra and lamina of C2 vertebra; C3-C8 spinal nerves through IVF above corresponding cervica vertebra, with the exception of C8 pair which exit via IVF between C7 and T1 vertebra)
12 thoracic segments forming 12 pairs of thoracic nerves (exit spinal column through IVF below corresponding vertebra T1-T12)
5 lumbar segment forming 5 pairs of lumbar nerves (exit spinal column through IVF, below corresponding vertebra L1-L5)
5 (or 1) sacral segments forming 5 pairs of sacral nerves (exit spinal column through IVF, below corresponding vertebra S1-S5)
1 coccygeal segment forming 1 pair of coccygeal nerves (exit spinal column through the sacral hiatus)
Because the vertebral column grows longer than the spinal cord, spinal cord segments do not correspond to vertebral segment in adults, especially in the lower spinal cord. In the fetus, vertebral segments do correspond near spinal cord segments. In the adult, however, the spinal cord ends around the L1/L2 vertebral level, forming a structure certain as the conus medullaris. For example, lumbar and sacral spinal cord segments are found between vertebral levels T9 and L2.
Although the spinal cord cell bodies end around the L1/L2 vertebral even, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from their respective roots to their point of exit from the vertebral column, the nerves of the lower spinal segment form a bundle called the cauda equina.
There are two regions where the spinal cord enlarges:
Cervical enlargement - corresponds roughly to the brachial plexus nerves, which innervate the upper upper limb. It includes spinal cord segments from about C4 to T1. The vertebral levels of the enlargement are roughly alike (C4 to T1).
Lumbosacral enlargement - corresponds to the lumbosacral plexus nerves, which innervate the lower limb. It comprises the spinal cord segments from L2 to S3, and is found about the vertebral level of T9 to T12.
SEE SOURCE Source(s): http://en.wikipedia.org/wiki/Spinal_cord
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