Neuro 1: Ascending Tracts of the Spinal Cord 1 – Flashcards
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What are the three *Posterior Horn Nuclei* of the spinal cord Gray Matter?
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SGR (Substantia Gelatinosa of Rolandi) NP (Nucleus Proprius CDN (Clark's Dorsal Nucleus)
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What are the Five *Anterior Horn Nuclei* of the spinal cord Gray Matter?
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Anterio/Posteriomedial Group Anterio/Posteriolateral Group Central Group
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What are the Three Subdivisions of the Spinal Cord White Matter?
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Dorsal, Lateral, Ventral Funiculus ("Highways")
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What are the 3 types of Fibers of the Spinal Cord White Matter?
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*Ascending* (Afferent): 4 each Conscious and Unconscious *Descending* (Efferent): Pyramidal, Extrapyramidal, Descending Autonomic *Intersegmental* (Associative): Connect segments and integrate their activities
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What are the four *Ascending* Sensory Tracts carrying *conscious* sensation?
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Fasciculus *Gracile* Fasciculus *Cuneate* Lateral/Ventral *Spinothalamic*
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What are the six *Ascending* Sensory tracts carrying *Unconscious* Sensation?
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Dorsal/Ventral/Rostral *Spinocerebellar* *Spinoolivary* *Spinotectal* *Cuneo* Cerebellar
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What are the Ascending and Descending Tracts of the Anterior Column?
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A: Anterior Spinothalamic D: Anterior Corticospinal, Tectospinal, Vestibulospinal, Reticulospinal
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What are the Ascending and Descending Tracts of the Posterior Column?
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A: Fasciculus Gracilis, Fasciculus Cuneatus D: *None*
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What are the Ascending and Descending Tracts of the Lateral Column?
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A: Lateral Spinothalamic, Dorsal/Ventral Spinocerebellar, Spinotectal, Spino-Olivary, Lissauer's Tract D: Lateral Corticospinal, Rubrospinal, Olivospinal, Tectospinal, Descending Autonomic
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Describe the following for the Fasciculus Gracilis? Tract and Position Sensation Carried Origin Termination
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TP: Posterior Column, Near Midline S: *Proprioception* and *Fine Touch* from *Lower 1/2 of the Body* O: Cells of *Dorsal Root Ganglion* T: Gracile Nucleus in Closed Medulla -> *Conscious Sensation* <-
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Describe the following for the Fasciculus Cuneatus? Tract and Position Sensation Carried Origin Termination
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TP: Posterior Column, Lateral to Gracile Tract S: Proprioception and *Fine Touch* from *Upper 1/2 of Body* O: Cells of *DRG* T: Cuneate Nucleus in Closed Medulla -> *Conscious Sensation* <-
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Describe the following for the Lateral Spinothalamic? Tract and Position Sensation Carried Origin Termination
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TP: Lateral Column S: *Pain and Temperature* opposite side body, below head O: Axons of *SGR* cross in front of central canal T: Posterolateral Ventral Nucleus of Thalamus (*PLVN*) -> *Conscious Sensation* <-
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Describe the following for the Anterior Spinothalamic Tract? Tract and Position Sensation Carried Origin Termination
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TP: Anterior Column S: *Crude Touch and Light Pressure* opposite side body, (Outside -> In = Sacral -> Cervical) O: Axons of Nucleus Proprius, cross T: *PLVN*, Thalamus -> *Conscious Sensation* <-
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Describe the following for the Posterior Spinocerebellar? Tract and Position Sensation Carried Origin Termination
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TP: Lateral Column S: *Proprioception of trunk + lower limb* to cerebellum O: Axons of *Clark Nucleus* on same side T: Cerebellar Hemisphere on same side -> *Unconscious Sensation* <-
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Describe the following for the Anterior Spinocerebellar? Tract and Position Sensation Carried Origin Termination
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TP: Lateral Column, in front of posterior spinocerebellar S: *Proprioception of lower limb* to cerebellum O: Axons at base of posterior horn, cross to opposite side T: Ascend to midbrain, *recross* to original side -> *Unconscious Sensation* <-
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Describe the following for the Spino-olivary? Tract and Position Sensation Carried Origin Termination
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TP: Lateral Column S: *Proprioception* O: Axons at base of posterior horn, cross to opposite side T: Inferior Olivary Nucleus to Cerebellum via olivo-cerebellar fibers -> *Unconscious Sensation* <-
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Describe the following for the Spinotectal? Tract and Position Sensation Carried Origin Termination
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TP: Lateral Column S: *Pain Temperature Touch* O: Axons at posterior horn cross to opposite side T: Superior Colliculus of Midbrain -> *Unconscious Sensation* <-
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What Gyrus do the Ascending Sensory Tracts of the White Matter reach?
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Postcentral Gyrus
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At what level of the Spinal Cord do the Lemnisci form?
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Pons
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What two Tracts form the Spinal Lemniscus?
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Lateral and Ventral Spinothalamic Tracts (Pain, Heat, Crude Touch)
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What two Tracts form the Medial Lemniscus?
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Gracile and Cuneate Tracts (Proprioception and Fine Touch)
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Describe the Dorsal Root Ganglion?
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1st Order Neuron Peripheral Process is in Receptors Central Processes transmit Sensation to 2nd Order Neuron
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If a DRG is transmitting *Pain, Temperature, or Crude Touch* information, where is the 2nd Order Neuron located?
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w/i the *Spinal Cord*
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If a DRG is transmitting *Proprioceptive or Fine Touch* information, where is the 2nd Order Neuron located?
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w/i the *Medulla*
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What happens after information is transmitted to a Second Order Neuron?
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It must *cross the midline* to reach the *Thalamus* on the other side
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What type of Neuron is the Posteriolateral Ventral Nucleus of the Thalamus?
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3rd Order Neuron -> Transmits to *Post Central Gyrus*
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What is the ONLY type of lesion that will result in Sensory Loss on the SAME side as the lesion?
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Lesion of a *1st Order Neuron* -> Otherwise Sensory loss will be on Contralateral side
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Describe the Course Taken by Nerve Fibers sensing Proprioception in the Lower Extremity to the Cerebrum?
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1st Order Neuron: DRG, enter Gracilis Tract 2nd Order: Relay at Caudal Medulla Cross Midline at Nucleus Gracilis Ascend w/i Medial Lemniscus to Pons/Midbrain to PLVNT 3rd Order Neuron: Relay to Postcentral Gyrus
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What is Tabes Dorsalis?
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Lesion in the Dorsal Column of Spinal Cord -> Loss of Proprioception (Ataxia w/ High Step and Unsteady Gate)
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Describe the Path of Pain and Temperature from Peripheral Nerves to Cerebrum?
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1st: DRG to Lissauer's Tract Lissauer's Cross Midline, and relay to *Substantia Gelatinosa of Rolandi* (2nd Order) These Axons ascend in Lateral Spinothalamic Tract, eventually forming the Spinal Lemniscus and Relaying at the PLVNT This then relays to Postcentral Gyrus
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Describe the Path of Crude Touch from Peripheral Nerves to Cerebrum
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1st: DRG relays to Nucleus Proprious (2nd Order) Fibers then Cross Midline at same level and Ascend as Anterior Spinothalamic Tract, eventually forming the Spinal Lemniscus and Relaying at the PLVNT This then relays to the Postcentral Gyrus
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What is Syringomyelia?
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Lateral Spinothalamic Tract Lesion -> Overenlargement of the Central Canal d/t cysts 2nd Order Neurons of Pain and Temp are affected as they Decussate in front of the Central Canal "Dissociated Sensory Loss" Pain and Temp Sensation Loss, but Not Light Touch or Proprioception
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Describe the Three Orders of Neurons involved in the Trigeminal Pathway?
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1st: Trigeminal Ganglion -> Then Relays to one of Three 2nd Neurons Mesencephalic, Main Sensory, or Spinal Nucleus These form the Trigeminal Lemniscus and Relay to the PMVNT (3rd Order) -> Relays to Postcentral Gyrus (Lower Part)
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What do the Three Nuclei of the Trigeminal Nerve sense, at what level do they reside?
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Mesencephalic: Propioception and Fine Touch (Pons) Main Sensory: Crude Touch (Midbrain) Spinal: Pain and Temperature (Medulla)
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What will the patient experience with Posterior Cord Syndrome?
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Loss of Proprioception and Vibration Sense Only (Gracilis and Cuneatus)
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What will the patient experience with Anterior Cord Syndrome?
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Loss of Pain, Temperature, and Motor Sense (Anteriolateral Spinothalamic Tracts, Lateral Corticospinal Tract, Anterior Horn Cells)
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What will the patient experience with Transverse Cord Lesion?
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Loss of Vibration, Pain, Temperature, Motor Sensation
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What will the patient experience with Hemicord Lesion?
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Loss of Vibration, Position, Motor on Ipsilateral Side Loss of Pain and Temperature on Contralateral Side
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What will be the First Part of the Body affected by a Central Cord Lesion?
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Arm Pain and Temperature Sensation
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Does the Dorsal or Ventral Spinocerebellar Tract Cross and then Re-Cross back to the ipsilateral side?
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Ventral Spinocerebellar -> Crosses at 2nd Neuron (Spinal Border Nucleus) Ascends Recrosses at *Superior Cerebellar Peduncle* -> Enters Cerebellar Cortex
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Does the Ventral Spinocerebellar Tract enter the Cerebellar Cortex via the Superior or Inferior Cerebellar Peduncle?
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Superior Cerebellar Peduncle
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Does the Dorsal Spinocerebellar Tract enter the Cerebellar Cortex via the Superior or Inferior Cerebellar Peduncle?
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Inferior Cerebellar Peduncle
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What is the shared 3rd Order Neuron associated with both the Dorsal and Ventral Spinocerebellar Tracts?
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No 3rd Order Neuron in these pathways
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What is the 2nd Order Neuron associated with the *Dorsal* Spinocerebellar Tract?
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Clark's *Dorsal* Nucleus
