The spinal cord lies within the vertebral canal of the vertebral column (spine).
Continues from the medulla oblongata of the brain stem to the cauda equina.
The cauda equina begins between L1 and L2 of the spine.
The spinal cord is approximately cylindrical in shape.
The dorsal (posterior) horn is the termination site for many afferent (sensory) neurones.
The ventral (anterior) horn contains the motor neurones which innervate skeletal muscle.
THORACIC AND LUMBAR LEVELS: Lateral horn (column in above picture).
– Contains preganglionic neurones belonging to the SYMPATHETIC division of the autonomic nervous system.
The white matter (surrounding the grey butterfly shaped grey matter) consists of longitudinally running nerves.
This matter is organised in to a series of tracts, either ascending or descending.
These delivery sensory information.
DORSAL columns (fasciculus gracilis and fasciculus cuneatus):
– Fine touch.
Fasciculus gracilis: Fibres from lower limb entering in at sacral, lumbar and lower thoracic levels.
Fasciculus cuneatus: Fibres from upper limb entering at upper thoracic and cervical levels.
Travels between the dorsal median sulcus and the dorsal horn on the spinal cord.
Both terminate at the medulla oblongata, nucleus fasciculus and cuneatus.
Information received in opposite side of the brain.
Two point discrimination test.
Flexing and extending toes or fingers while patient has eyes closed (inform the first time then ask what position after).
128 tuning fork on joint lines.
SPINOTHALAMIC tracts (lateral and anterior)
– Coarse touch.
After leaving parent cell bodies, axons move to the opposite side of the cord via the ventral white commissure.
Lie laterally and ventrally to the ventral horn.
Majority terminate in the thalamus.
Cold tuning fork temperature.
Neurotip: sharp and blunt tests (crude touch or pain).
SPINOCEREBELLAR tracts (ventral and dorsal)
– Muscle and joint receptors to cerebellum.
Cell bodies originate from base of dorsal horn.
Dorsal and ventral tracts located near dorsolateral and ventrolateral cord surfaces.
Terminate in the cerebellar cortex.
These deliver response or reflex information.
– Indirectly increase muscle tone.
Originates from red nucleus of midbrain.
Cross the ventral tegmental decussation.
Descend to spinal cord to pass along it ventrolaterally.
– Impulses which regulate autonomic functions.
– Muscle tonus.
– Somatic movement.
PYRAMIDAL tracts (lateral and anterior corticospinal)
– Motor impulses.
– Voluntary movement.
Arise from cell bodies in the cerebral cortex.
Pass through ventral portion of the pons.
Form two prominent columns at the medulla oblongata.
- Cauda Equina Syndrome (garystewbellamy.wordpress.com)
- An overview of the central nervous system. (epsomtissuetech.wordpress.com)