Term
| What does the anterolateral system carry? What is another name for it? |
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Definition
-It carries type III and IV fibers
-Aka the spinothalamic tract |
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Term
| Where are its cell bodies? Where does it cross? |
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Definition
-First, as always, is in the DRG
-Second is about two segments up in the dorsal horn
-Last is in the VPL nucleus of the thalmus
-It crosses right after the second cell body in the dorsal horn, through the ventral White commissure, and into the spinothalamic tract
-This low decussation is its most important path feature |
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Term
| What is the overall path? |
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Definition
| -spinal nerve-->lissauers tract-->dorsal horn (first synapse)-->ventral white commissure-->spinothalamic tract-->VPL (second synapse)-->postcentral gyrus |
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Term
| Where will we see analgesia when a spinothalamic tract lesion? |
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Definition
-Analgesia means absence of pain
-It will start about two segments below the lesion, on the contralateral side |
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Term
| What are the spinocerebellar pathways? |
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Definition
-They carry proprioceptive info (from type I fibers mostly) to the cerebellum
There are two of them;
-Dorsal spinocerebellar tract; lower proprioception info
-Cuneocerebellar tract; upper proprioception info |
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Term
| Where are the cell bodies for the spinocerebellar pathways? Where are the fibers from? |
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Definition
-The fibers are coming from those type I and II fibers; they send some branches to lower motor for reflexes, and now also to the spinocerebellar tracts for coordination
-This is a unique kind of sensory in that it only has a two neuron pathway (much like motor)
-The first cell body is DRG
-The second is in **Clarke's nucleus (T1-L2) for the dorsal tract, or in the *external cuneate nucleus of the medulla for the cuneocerebellar tract |
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Term
| What is the pathway? Include how it gets into the cerebellum? |
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Definition
DRG-->Clarke/external cuneate nucleus-->thru *inferior cerebellar peduncle-->cerebellar cortex
-Clarke's nucleus is in the intermediate horn btw |
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Term
| What is a hereditary disease where we may see spinocerebellar pathway involvement (along with others) |
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Definition
-Friedreich ataxia
-May involve the cerebellum, dorsal columns, and corticospinal tracts also |
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Term
| What is Brown-Sequard syndrome? What can we expect? |
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Definition
-This is hemisection of the spinal cord
-We can expect *two ipsilateral system losses below the lesion (touch/proprioception and motor) and *one contralateral loss (pain/temp)
-The paralysis will be mostly *spastic, except for at the actual level of the lesion where the lower motor neurons are lesioned (flaccid there)
-Pain and temp loss will actually be ipsilateral for a few segments also, because of Lissnauer's tract |
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Term
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Definition
-The lower motor neurons in the ventral horn, bilaterally
-Gives progressive flaccid paralysis |
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Term
| What does tabes dorsalis affect? What causes it? What are the clinical signs? |
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Definition
-Bilateral dorsal columns
-Associated with neurosyphilis (spreads from DRG)
-Because of loss of proprioception and touch, there will be a high-step stride
-Also get incontinence (no reflex muscle tone)
-Often get **Argyll Robertson pupil (no light reflex) which is highly diagnostic for neurosyphilis |
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Term
| What does ALS involve? What is its other name? How does it present? |
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Definition
-ALS, or Lou Gehrig's disease, involves both upper and lower *motor neurons (ventral horn and corticospinal)
-Typically starts in the cervical region
-Results in flaccid paralysis in upper limbs and spastic paralysis in lower limbs |
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Term
| What is spared in an anterior spinal artery occlusion? |
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Definition
-Only the dorsal columns
-Will result in bilateral spastic paresis below the lesion |
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Term
| What is affected in subacute combined degeneration? What is the cause? |
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Definition
-Corticospinal tracts, dorsal columns, and spinocerebellar tracts are affected bilaterally
-Essentially, lower motoneurons, and pain & temp are left
-Caused by patchy demyelination secondary to B12 deficiency seen in pernicious anemia (AIDS)
-Will give bilateral *spastic paresis AND *touch altercation below lesion sites |
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Term
| What is syringomyelia and how will it progress? |
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Definition
-This is the cavitation of the central canal, starting *cervical and going down (upper effects, then lower)
-The earliest sign will be bilateral loss of **(1) pain and temperature (ventral white commissure is first affected)
-Will work its way into the ventral horns next, causing *(2) bilateral flaccid paralysis
-If it continues it will also involve the descending hypothalamic fibers causing *(3)Horner's syndrome |
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Term
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Definition
-*Exacerbations and remissions are the best give away
-*Optic nerve involvement is also highly typical (often monocular)
-Results from widespread CNS autoimmune demyelination
-Causes spastic paresis, paresthesias, ataxia, & diplopia |
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Term
| What is the premise for Romberg's test? How does it work? |
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Definition
-That a person needs at least two out of three for proprioception, vision, and vestibular function (balance)
-You have the patient stand with feet together and eyes closed, and if they sway/fall, the problem is sensory
-If the problem is cerebellar they will sway even with eyes open |
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