Somatosensory Review Flashcards
Modality of Dorsal column/ ML
fine touch, vibration, limb position
Modality of Anterolateral
pain/temp/crude touch
Major tract of Dorsal column/ML
F. gracilis
F. cuneatus
–> at medulla, both enter Medial lemniscus
Major tract of Anterolateral tract
- spinoreticular
- spinothalmic
- spinomesenphalic
Placement of tract for Dorsal Column/ML
Located dorsally, middle part of dorsal sp cd on both sides—- posterior fasciculus
Placement of tract for Anterolateral
Ventral, lateral sp cd on both sides
Diversity of pathways: Dorsal Column
1 path to medulla (through sp cd)
1 major path to thalamus
Diversity of pathway for anterolateral system
3 major that run together in sp cd but terminate in dif places
Spinothalmic: thalamus
Spinoreticular: reticular formation in medulla or pons
Spinomesenphalic: midbrain PAG, superior colliculus
Crossing pt for Dorsal column/ML
X to opp side in ONE place = Sensory decussation in caudal medulla where they then synapse and head up Medial lemniscus
Crossing pt for Anterolateral system
X to opp side in sp cd and cross all along at levels near where primary afferents enter (w/in 2-3 segments of entering)
Results of damaged sp cd: Dorsal Column
Ipsilateral loss of tactile, vibration, jt position below level of lesion
Result of damaged sp cd: Anterolateral
Contrlateral loss of pain and temp w/in 2-3 cord segments of lesion
By the ________ and _______ both pain and touch fibers are simular and all information has crossed
thalamus and cortex
Lesions in thalamus and cortex for both pain and fine touch will produce ________ deficiets
contralateral
Somatosensory information goes _____ thus lesion will cause loss of sensation _____
up
below
A patient presenting with alternating sensory loss is key for what kind of lesion
Unilateral lesions in spinal cord
Sugical cutting of dorsal root
Use for pain relief
cut dorsal roots that innervate affected dermatome
Rhizotomy
Rhizotomy will result in
loss of fine discr, jp, vibration AND pain and temperature in just dermatome of affected cut roots IPSILATERAL to lesion
-pain often reoccurs
Surgical cutting of anterolateral fiber tracts in cord for pain relief in terminally ill
cut 2-3 above area you want to relieve pain
Cordotomy
Cut one side anterolateral tract for cordotomy you will lose pain/temp on the _____
contrallateral side
Loss of fine touch/pain temp in specific dermatome ______ results in loss of feeling in foot, back of calf and shin
L4/L5/S1
–Herniated disk
Glove and stocking deficeits result from
Peripheral neuropathy (diabetes) affects multple derms and d/t
A herniated disk in L4/L5 will affect
L5 spinal nerve
Bilateral loss of all sensation below lesion and loss of motorl control and voluntary musle contration below lesion
Complete cord transection
causes of cord transection
trauma/tumor/bullet or knife wound
Bilateral loss of pain and temp below lesion and often weakness, ususally spares DCs so fine discriination and jp is okay
Anterior cord syndrome
cause of anterior cord syndrome
anterior spinal artery syndrome
frxt vertebrae, contusion of sp cd
infarct or ischemia form anterior spinal artery, emoblism or compresion of artery
loss of fine touch and discrimination, vibration and joint position on both sides with pain and temp okay
posterior cord syndrome
posterior cord syndrome affects
dorsal columns
caues of post. cord syndrome
tabes dorsalis (demyl or degen from syphalis) -tumor in dorsal area trauma
Central cord syndrome: small lesion: usually cervicle ressults in
bilateral loss of pain and temp in derms of spinal levels WITH THE LESION and sparing of dorsal columns and tactile sense as well as sparing anterolateral tracts below lesion
bilateral loss of pain and temp in derms of spinal levels WITH THE LESION and sparing of dorsal columns and tactile sense as well as sparing anterolateral tracts below lesion
Central cord syndrome
central cord syndrome affects where?
2nd order anterolateral fibers that are crossing
Syringomyelia causes
central cord syndrome
loss of pain and temp on level of lesion bilaterally only
cyst in the central canal
bilateral loss of fine discrimination, joint position below lesion
can affect motor neurons in ventral horn so loss of motor control
can affect anterolateral tracts–> bilateral loss of pain/temp below lesion
may bet sacral sparin
large central cord syndrome
why are sacral regions spared in large central cord syndrome
because they are on the periphery
Hemisection of cord called
brown-sequard syndrome
fine discriniation and pain/temp lost on atlernating sides
ipsi loss of fine touch/discrimination
contra loss of pain/temp w/in 2-3 segments below lesion
loss of ALL sensation at level of lesion
ipsilateral paralysis and loss of muscle control
Brown-sequard syndrome or hemisection of cord
hemisection of cord
fine discriniation and pain/temp lost on atlernating sides
ipsi loss of fine touch/discrimination
contra loss of pain/temp w/in 2-3 segments below lesion
loss of ALL sensation at level of lesion
ipsilateral paralysis and loss of muscle control
contralateral loss of fine discriminiation AND
contralateral loss of pain/temp must be lesion in
VPL of thalamus
face intact
loss of pain/temp/fine touch on contralateral side of body means
VPL of thalamus lesion
VPM spared
contralateral loss of fine discrimination pain/tem in face and head while sesnation in body intact
VPM lesion
lesion slightly lateral to the middle of the SI cortex results in
loss of fine touch/pain/temp on contralateral side of body on HAND AND WRIST
lesion very laterally of the SI cortex results in
loss of fine touch/pain/temp on contralateral side of FACE/tongue
Brainstem lesion in lateral medulla results in
interuption of anterolateral pathways and spinal trigeminal tract or nucleus
loss of pain/temp body on CONTRA side
loss in pain/temp face IPSlateral
loss
loss of pain/temp on Contralateral side too
lesion in lateral medulla
the fine touch on face is spared bc that doesn’t descend to the spinal tract like the pain fibers do
If entire 1/2 of medulla is lesioned (opposed to just the lateral portion)
loss in fine touch in body on contralateral side in addition to:
loss of pain/temp body on CONTRA side
loss in pain/temp face IPSlateral
loss
loss of pain/temp on face Contralateral side too
if you see olives and pyramids we know we are in
rostral medulla
Lesion in the medial lemniscus on the rostral medulla on left side of body results in
loss of vibration on right side of body below level of neck
- -face doesn’t come in until level of pons
- -the fibers have already crossed by this pont
GSW interupts the entire left half of sp cd at thoracic C6, we see loss of
loss of pain and temp on right
loss of fine touch and discrimination on left
Pt with loss of pain and temp sensation on right half of body below level of neck and loss of fine discrmination on right half of body from neck below.. Pt has infarct where
left VPL
