Chapter 4: Spinal Cord (continued) Flashcards
The fasiculus cuneatus carries fibers from what spinal cord segments?
T5 and up
The DCML pathway is located in what part of the spinal cord?
dorsal columns
The fasiculus gracilis carries fibers from which spinal cord segments?
T6 and below
Where in the thalamus are the 3rd neurons of the DCML?
ventropostero-lateral nucleus VPL
What sensations are loss with damage to the DCML?
- joint position sensation
- vibratory and pressure sensations
- 2 point discrimination
- loss of ability to identify the characteristics of an object (asterognosis) (consistency, form, and shape)
How is Romberg sign tested?
asking the patients to place their feet together. If there is marked deterioration of posture (if patient sways) with eyes closed, this is a positive Romberg sign (DC lesion)
If patent has balance problems and tends to sway with eyes open = cerebellar damage
What sensations does the anterolateral pathway send?
pain, temperature, and crude touch sensations from the extremities and trunk
What is another name for the anterolateral system?
spinothalamic tract
Lissaur tract?
tract taken by anterolateral dorsal root fibers where they ascend or descend the spinal cord 1-2 segments down or up in the spinal cord
Where is the ventral white commissure located?
below the central canal of the spinal cord
Where do anterolateral system fibers cross the midline?
in the ventral white commisure
Where in the thalamus does the spinothalamic tract terminate?
in the VPL nucleus of the thalamus
Cells from the VPL that have received spinothalamic tract cords send pain and temperature information to which part of the brain?
primary somatosensory cortex in the postcentral gyrus
What sensory information does the spinocerebellar tract carry?
unconscious proprioceptive input from muscle spindles and GTOs to the cerebellum where this information is used to help monitor and modulate movements
What are the 2 major spinocerebellar pathways?
- dorsal spinocerebellar tract
- cuneocerebellar tract
The dorsal spinocerebellar tract carries information from what part of the body?
carries input from the lower extremities and lower trunk
The cuneocerebellar tract carries information from what part of the body?
carries proprioceptive input to the cerebellum from the upper extremities and upper trunk
Where are the cell bodies of the dorsal spinocerebellar tracts found?
in Clarke’s nucleus, which is situated in the spinal cord from T1 to L2
Where are the cell bodies of the cuneocerebellar tract found?
in the medulla in the external cuneate nucleus
What is the most common hereditary condition involving degeneration of the spinocerebellar pathways?
Friedreich ataxia
What are the areas of the spinal cord affected by Friedreich ataxia?
spinocerebellar tracts, dorsal columns, corticospinal tracts, an cerebellum
How to identify a cord section: If there is a large ventral horn?
C5 -T1 or L2 - S2
How to identify a cord section: If there is not a large ventral horn?
T1-L1, C1-C4
How to identify a cord section: If both dorsal columns are present.
above T5
How to identify a cord section: If both dorsal columns are not pressent?
below T5
How to identify a cord section: If there is a lateral horn?
T1 - L2
How to identify a cord section: If lateral horns are not present?
C1 - C8 or L3 - S5
What is Brown-Sequard Syndrome?
hemisection of the cord causing lesion of each of the 3 main neural systems
What is a hallmark sign of Brown Sequard syndrome?
patient presents with 2 ipsilateral signs and 1 contralateral sign
What are the 3 Ps of Tabes Dorsalis?
paresthesias (pins-and-needles sensations), pain, polyuria
also will have Romberg sign
Spastic bladder results from lesions found where in the spinal cord?
lesions of the spinal cord above the sacral spinal cord levels
The pathogenesis for spastic bladder?
results from lesions of the spinal cord above the sacral spinal cord levels
Pathology of polio?
results from a relatively selective destruction of lower motorneurons in the ventral horn by poliovirus
Symptoms of polio
a. flaccid paralysis
b. muscle atrophy
c. fasciculations
d. areflexia
What levels of the spinal cord is polio typically found?
lumbar levels
What does ALS stand for?
amyotrophic lateral sclerosis
What is another name for ALS?
Lou Gehrig disease
What levels of the spinal cord does ALS typically affect?
begins at cervical levels of the cord and progress either up or down the cord
ALS symptoms.
a. progressive spinal muscular atrophy (ventral horn)
b. primary lateral sclerosis (corticospinal tract)
- spastic paralysis in lower limbs
- increased tone and reflexes
- flaccid paralysis in upper limbs
c. Common in cervical enlargment
What part of the spinal cord does occlusion of the ASA affect?
ASA (anterior spinal artery)
interrupts blood supply to the ventrolateral parts of the spinal cord
What major tracts of the spinal cord are affected with occlusion of the ASA?
corticospinnal tracts and spinothalamic tracts
What is syringomyelia?
a disease characterized by progressive cavitation of the central canal
What spinal cord levels are typically affected when one has syringomyelia?
usually in the cervical spinal cord level
Horner syndrome manifestation?
ptosis
miosis
anyhydrosis
Symptoms of syringomyelia?
a. bilateral loss of pain and temperature at the level of the lesion
c. as disease progresses, there is muscle weakness; eventually flaccid paralysis and atrophy of the upper limb muscles due to destruction of ventral horns
What is Tabes dorsalis a manifestation of?
neurosyphilis
Pathology of Tabes dorsalis?
causes bilateral degeneration of the dorsal roots and secondary degeneration of the dorsal columns
What are symptoms of Tabes Doralis?
a. “paresthesias, pain, polyuria”
b. associated with late-stage syphilis, sensory ataxia, positive Romberg sign: sways with eyes closed, Argyll Robertson pupils, suppressed reflexes
c. common at lumbar cord levels
Pathology of atonic bladder?
- results from lesions to the sacral spinal cord segments of sacral spinal nerve roots
- loss of pelvic splanchnic motor innervation with loss of contraction of the detrusor muscle results in a full bladder with a continuous dribble of urine from the bladder
Pathology of infantile bladder?
Developmental Immaturity
The bladder behaves as if it is still in the developmental phase, commonly seen in infants where voiding is involuntary and reflexive.
There is a lack of proper maturation of:
Cortical control: Necessary for voluntary urination.
Neural pathways: Specifically the pontine micturition center, which coordinates bladder and sphincter function.
Syringomyelia may present with what other condition?
Arnold-Chiari I malformation
What is the buzz word for pain caused by syringomyelia?
“belt-like” or “cape like” loss of pain and temperature
When is subacute combined degeneration typically seen?
in cases of B12 deficiency sometimes related to pernicious anemia
Where is the myelin loss in subacute combined degeneration found?
patchy losses of myelin in dorsal columns and lateral corticospinal tract
What are the symptoms of subacute combined degeneration?
a. vitamin B12, pernicious anemia
b. demyelination of the:
- dorsal columns (central and peripheral myelin)
- spinocerebellar tracts
- corticospinal tracts (CST)
c. upper thoracic or lower cervical cord.
Symptoms of ASA occlusion?
a. DC spared
b. all else bilateral signs
c. common at mid thoracic levels
d. spastic bladder
Brown Sequard Syndrome symptoms.
a. DC: ipsilateral loss of position and vibratory senses at and below level of the lesion
b. spinothalamic tract: contralateral loss of pain and temp 1-2 segments below lesion and ipsilateral loss at the level of the lesion
c. CST: ipsilateral paresis below the level of the lesion
d. LMN: flaccid paralysis at the level of the lesion
e. descending hypothalamics: ipsilateral Horner syndrome (if cord lesion is above T1)
