TUT Spinal Cord Flashcards
What is the lateral horn?
(intermediolateral cell column, found between T1-L2, motor neurons for preganglionic sympathetic fibres)
Anterior white commissure, what happens here?
anterior white commissure
Site where spinothalamic pathway cross
Difference between descussation of the lateral and anterior corticospinal tract?
Lateral cross at Pyramids in medulla (brain stem)
Course: Motor information for the limbs originates in cortex, crosses over in the pyramids, and descends contralaterally in the lateral white matter
as part of the LCST
Anterior cross at: Those that do cross, do so at the spinal level where they terminate. DOUBLE CROSS= Ipsilateral effect.
(Course: Enters the pyramids but does not cross, and descends ipsilaterally in the
ventral white matter as part of the ACST. Some fibres will then cross at the level in which they terminate)
Course of gracile fasciculus?
Sensory information (fine touch, pressure) for the lower limbs originates in periphery, travels in through the dorsal root ganglia and into the dorsal root to enter the spinal cord (without crossing), it ascends ipsilaterally in the gracile fasciculus where it crosses over in the caudal medulla becoming the medial lemniscus travelling up to the cortex
Course of cuneate fasciculus?
Sensory information (fine touch, pressure) for the upper limbs originates in periphery, travels in through the dorsal root ganglia and into the dorsal root to enter the spinal cord (for Thoracic spinal level T5/T6 and above) without crossing, it ascends ipsilaterally in the cuneate fasciculus where it crosses over in the caudal medulla becoming the medial lemniscus travelling up to the cortex
Course of the spinothalamic tract?
Sensory information (pain, temperature) originates in periphery, travels through the dorsal root ganglia and into the spinal cord, ascends or descends 1-2 levels in Lissauer’s tract (ipsilaterally) synapsing in the dorsal horn, and then crosses the midline in the anterior white commissure, where it ascends contralaterally in the spintothalamic tract up to the cortex
Most important point is the fact that it crosses in the cord!
Course of the posterior spinocerebellar tract?
Sensory information (proprioception - musculature) originates in periphery, travels through the dorsal root ganglia and into the spinal cord without crossing, and ascends ipsilaterally in the dorsal column until it reaches Clarke’s nucleus (C8-L3) where it synapses and then ascends as the PSCT. All ipsilateral for this pathway, but remind them of the ASCT which is also ipsilateral but crosses 2X!
What is artery of adamkiewicz?
Typically arises from a left posterior intercostal artery at the level of the 9th to 12th intercostal artery, which branches from the aorta,
Supplies: The lower 2/3 of the spinal cord via the anterior spinal artery.
What symptoms you would
expect if you examined a patient with a right-sided Brown-Séquard lesion on the level of the 7th thoracic vertebra.
Sensory deficits?
- loss of fine touch, vibration sense on the right below T7
- Loss of pain and temperature sensation on the left below T7
Motor deficitis?
- loss of motor function on the right below T7
Your patient presents with anterior cord syndrome at the 5th thoracic vertebra resulting from blockage of the anterior spinal artery. Sensory and motor deficits?
Sensory deficit:
- Loss of anterior white commisure and spinothalamic = Bilateral loss of pain and temp at and below T5
- Sparing of fine touch, proprioception and vibration as gracilis and cuneate fasciculus are not affected
Motor deficit:
-Lateral and anterior corticospinal tracts damaged = Acute bilateral loss of motor function below T5
Central spinal cord syndorme at 7th cervical vertebra e.g. syringomyelia. Sensory and motor deficits?
Sensory deficit:
Damage to anterior commissure (spinothalamic pathway) = Bilateral gradual loss of pain and temp in sensation in hands at C7
Varying loss of bilateral sensory loss below C7. Initial sparing of fine touch, proprioception and vibration in dorsal columns. However Cuneate and Gracile gradually become partially affected with loss of proprioception
Motor deficit:
Gradual onset of bilateral diffuse muscle atrophy beginning in the hands due to damage to Lateral Corticospinal Tract and ventral Horns.
Rubrospinal tract:
What info?
Do fibres corss?
If so, where?
Info:
Activation of flexor muscles in the upper limbs and inhibition of extensors on the contralateral side.
If corticospinal tract interrupted (stroke) the rubrospinal influence on the upper limbs becomes apparent (contralateral (to side of stroke) flexed upper limb)
Cross at the midbrain
MOTOR
Reticulospinal tract:
What info?
Do fibres corss?
If so, where?
Info:
The two reticulospinal tracts have differing functions:
The medial reticulospinal tract arises from the pons. It facilitates voluntary movements, and increases muscle tone.
The lateral reticulospinal tract arises from the medulla. It inhibits voluntary movements, and reduces muscle tone.
No crossing
MOTOR
Vestibulospinal tract:
What info?
Do fibres corss?
If so, where?
Info:
There are two vestibulospinal pathways; medial and lateral. They arise from the vestibular nuclei, which receive input from the organs of balance. The tracts convey this balance information to the spinal cord.
Fibres in this pathway control balance and posture by innervating the ‘anti-gravity’ muscles (flexors of the arm, and extensors of the leg).
No crossing
MOTOR
Tectospinal tract:
What info?
Do fibres corss?
If so, where?
Info:
This pathway begins at the superior colliculus of the midbrain. The superior colliculus is a structure that receives input from the optic tract. The neurones then quickly decussate, and enter the spinal cord. They terminate at the cervical levels of the spinal cord.
The tectospinal tract coordinates movements of the head in relation to vision stimuli.
Crosses at midbrain
MOTOR
