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SPINAL CORD DISEASESParaparesis

Quadriparesis

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Where does the spinal cord end?

Adult spinal cord - 45 cm long Originates at the medulla Ends at the conus medullaris

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Fetal life

Until the third month of fetal life Spinal cord is as long as the vertebral

canal After the third month of fetal life

Vertebral column elongates faster than the spinal cord

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Adults

Vertebral column is longer than the spinal cord

Common cause of spinal cord disease Diseases of the vertebrae

Fracture Infection Secondary deposits

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Adults – L 1

Spinal cord ends at the lower level of first lumbar vertebral body

Cervical enlargement Innervate the upper extremities

Lumbar enlargement Innervate the lower limbs

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Cauda equina (horse's tail) Different growth rates of the cord

and spine Vertebral column is longer than the

cord Cord segments are above their

corresponding vertebrae Lumbosacral region

Nerve roots descend almost vertically below the cord to form the cauda equina

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Spinal cord has 31 segments 8 cervical

Only seven cervical vertebrae 12 thoracic 5 lumbar 5 sacral

Sacrum formed by fusion of 5 vertebrae

Few small coccygeal

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Each segment

Ventral (motor) root Exit from the vertebral column

through intervertebral foramina Dorsal (sensory) root

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Ventral (anterior) roots

Alpha motor neuron axons To the extrafusal striated muscle

fibers Gamma motor neuron axons

To the intrafusal muscle fibers

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Dorsal (posterior) roots

Sensory Convey sensory information from the

skin, joints, and muscles to the central nervous system

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C1 to C7 spinal nerves

Exit above the same-numbered vertebral bodies C2 spinal nerve root exits above C2

vertebra C8 root

Exits between vertebral bodies C7 and T1

All the subsequent spinal nerves exit below the same-numbered vertebral bodies.

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SPINAL CORD LEVELS RELATIVE TO THE VERTEBRAL BODIES

Spinal Cord LevelCorresponding Vertebral Body

Upper cervical Same as cord level

Lower cervical 1 level higher

Upper thoracic 2 levels higher

Lower thoracic 2 to 3 levels higher

Lumbar T10-T12

Sacral T12-L1

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T4 SPINE

Level with the sixth CORD segment T12

S1cord segment

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Hallmark of spinal cord disease

Loss of motor and sensory functions below the level of the lesion

Loss of autonomic functions occurs below the level of the lesion Loss of urinary bladder tone Paralytic ileus

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Horizontal level in the body

Sensory level Damage to the ascending spinothalamic

tract Motor level (i.e., paraplegia or

quadriplegia) Damage to the descending corticospinal

and other motor tracts………..

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