Protection of Spinal cord
Bone vertebrae
Meaninges
CSF surround and protect the delicate nervous tissue of spinal cord.
Spinal meninges
Protect three layer of tissue.
Spinal meninges continuous with cranial meninges.
1. Dura mater; outer
2. Arachnoid mater; intermediate
3. Piamater; inner
1. Dura mater; outer
Spinal dura mater is most external of meninges. It extends from foramen magnum to filum terminale.
2. Arachnoid mater; intermediate
Spinal arachnoid mater is located between dura mater and pia mater. They form gap between arachnoid and pia mater called subarachnoid space, this is where CSF is found.
3. Piamater; inner
Spinal piamater is innermost of meninges. It is thin membrane that covers spinal cord, nerve root and their blood vessels. Inferiorly spinal pia mater fuses with filum terminale.
Cross section of spinal cord shows the following-
1. Central canal; contain CSF
2. Grey mater; H shaped, dark portion
White mater; grey mater in center, surrounded by white mater
1. Central canal
In centre of grey portion is small space called central canal containing CSF. It extends entire length of spinal cord.
2. Grey mater
Grey mater is dark portion of H-shape. Gray mater of spinal cord consists of nerve cell bodies, rich network of blood vessels.
Grey mater composed of 3 pairs of column of neurons.
1. Posterior columns of grey mater
These are composed of cell bodies that are stimulated by sensory impulses from periphery of body.
2. Anterior column of grey mater
These are composed of cell bodies of lower motor neurons that are stimulated by upper motor neurons.
3. White mater
White mater is composed mainly of bundles of mylinated axons of neurons that allow communication between different parts of spinal cord and between spinal cord and brain.
These fibers run in three direction-
Ascending; up to higher centers; sensory input
Descending; down to spinal cord from brain, spinal cord to lower motor
Transversely; across from oneside of spinal cord to another.
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