Spinal cord is resent in spinal canal or vertebral canal of vertebral column. It is extended from foramen magnum to 11 lumber vertebra. In new born infants, extend to 3 or 4 lumber vertebra. Spinal cord is swollen in cervical and lumber region which are called cervical and lumber enlargement. The length of spinal cord ranges from 42 to 45 cm. Its diameter is about 2cm.
Structure of spinal cord
(1) Conus medullaris: It is last tapering ends of spinal cord, its ciliated central canal is called Vth ventricle.
(2) Cauda equina : A horse tail-like collection of roots of spinal nerves at inferior end of the spinal cord. Some spinal nerves arise from inferior part of cord do not leave vertebral column at some level as they exit from spinal cord. The roots of these nerves angle inferiorly in vertebral canal from end of spinal cord like wisps of hair.
(3) Filum terminals: It is extension of piamater below conus medullaries up to coccyx. In frog spinal cord also extends upto end of vertebral column.
(4) Cisterna terrninalis : It is last dilation of subarachnoid space below 1st lumbar vertebra. It is a proper site for lumber puncture or spinal tap, which is done to drain C.S.F out (5 to 10 ml). This C.S.F is used in diagnosing many diseases of CNS like meningitis, cyphalis, inter cranial pressure, menningococcal interaction etc.
(5) Meninges : Like brain, spinal cord is also enclosed with in three membranes. In this case duramater does not remain attached with the vertebra, instead there is a space betweep duramater and vertebra called epidural space. The epidural space is filled with a fluid. The distribution of duramater and piamater in spinal cord is the same as that of brain.
(1) Central canal: In the centre of spinal cord, there is a canal called central canal. It is filled with cerebrospinal fluid. Central canal is continuous with 4th ventricle of medulla oblongata.
(2) Dorsal fissure: In the mid dorsal line, there is a groove extending throughout its length. (3) Ventral fissure : It is also a groove situated in the mid ventral line throughout the length of spinal cord.
(4) Dorsal septum : It is a partition extending from dorsal fissure to central canal.
(5) Grey matter : It lies around the central canal in the form of a butterfly and sub-divided into 3 horns, surrounded by white mater.
(6) Dorsal horns : It is like horn of grey matter on the dorsal side.
(7) Ventral horns : On the ventral side of the grey matter are horn like structures the ventral horns.
(8) Lateral horns : These are horns on the lateral side of grey matter.
(9) White matter : White matter is present around grey matter. Dorsal and ventral horn, divide white matter into 3 broad area on each side —
(i) Anterior (ventral) white columns
(ii) Posterior (dorsal ) white columns
(iii)Lateral white columns.
Structure of spinal cord
(1) Conus medullaris: It is last tapering ends of spinal cord, its ciliated central canal is called Vth ventricle.
(2) Cauda equina : A horse tail-like collection of roots of spinal nerves at inferior end of the spinal cord. Some spinal nerves arise from inferior part of cord do not leave vertebral column at some level as they exit from spinal cord. The roots of these nerves angle inferiorly in vertebral canal from end of spinal cord like wisps of hair.
(3) Filum terminals: It is extension of piamater below conus medullaries up to coccyx. In frog spinal cord also extends upto end of vertebral column.
(4) Cisterna terrninalis : It is last dilation of subarachnoid space below 1st lumbar vertebra. It is a proper site for lumber puncture or spinal tap, which is done to drain C.S.F out (5 to 10 ml). This C.S.F is used in diagnosing many diseases of CNS like meningitis, cyphalis, inter cranial pressure, menningococcal interaction etc.
(5) Meninges : Like brain, spinal cord is also enclosed with in three membranes. In this case duramater does not remain attached with the vertebra, instead there is a space betweep duramater and vertebra called epidural space. The epidural space is filled with a fluid. The distribution of duramater and piamater in spinal cord is the same as that of brain.
(1) Central canal: In the centre of spinal cord, there is a canal called central canal. It is filled with cerebrospinal fluid. Central canal is continuous with 4th ventricle of medulla oblongata.
(2) Dorsal fissure: In the mid dorsal line, there is a groove extending throughout its length. (3) Ventral fissure : It is also a groove situated in the mid ventral line throughout the length of spinal cord.
(4) Dorsal septum : It is a partition extending from dorsal fissure to central canal.
(5) Grey matter : It lies around the central canal in the form of a butterfly and sub-divided into 3 horns, surrounded by white mater.
(6) Dorsal horns : It is like horn of grey matter on the dorsal side.
(7) Ventral horns : On the ventral side of the grey matter are horn like structures the ventral horns.
(8) Lateral horns : These are horns on the lateral side of grey matter.
(9) White matter : White matter is present around grey matter. Dorsal and ventral horn, divide white matter into 3 broad area on each side —
(i) Anterior (ventral) white columns
(ii) Posterior (dorsal ) white columns
(iii)Lateral white columns.
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