Tactile and Proprioceptive Pathways - Stephens Flashcards
What are the two tactile pathways? Which one is important clinically?
Ventral (anterior) spinothalamic pathway - crude tactile
Posterior column/medial lemniscal pathway - precise
–**this is only clinically important pathway
What are the two tactile pathways?
Ventral (anterior) spinothalamic pathway - crude tactile
Posterior column/medial lemniscal pathway - precise
What is the ventral spinothalamic pathway? aka Anterior
Crude tactile and vibratory sense
Clinically not tested
Know what you are in contact with but not what it is
What is the posterior column/medial lemniscal system?
Discerning, aggressive touch
Very rapid
What is the posterior column/medial lemniscal system?
Discerning, aggressive touch
Very rapid
What is the Ventral/Anterior spinothalamic pathway?
1 neuron enters and ascends 6-10 segments (can descend - usually reflexes)
1 neuron synapses on 2 in the nucleus proprius
2 neuron crosses over and ascends in the anterior spinothalamic tract – at brainstem becomes spinal lemniscus
2 neuron synapses on 3 in VPL nucleus
3 neuron ascends in internal capsule and goes to primary somesthetic cortex
Where does the precise tactile pathway (Posterior colums/medial lemniscal) begin and ascend in?
UE - ascends in fasciculus cuneatus
LE - ascends in fasciculus gracilis
In precise pathway where do 1 and 2 neurons synapse?
(from UE - fasciculus cuneatus) on nucleus cuneatus
(from LE - fasciculus gracilis) on nucleus gracilis
Where do 2 neurons in precise pathway ascend?
Medial lemniscus
Where do 2 and 3 neurons in precise pathway synapse? Where do they ascend to?
Synapse - VPL
Ascend - 1 somesthetic cortex
Where do the sacral descending branches of primary neurons in posterior columns go?
Fasciculus triangularis
Where do the sacral descending branches of primary neurons in posterior columns go?
Fasciculus triangularis
Where do the lumbar descending branches of primary neurons in posterior columns go?
Fasciculus septomarginalis
Where do the cervical descending branches of primary neurons in posterior columns go?
Fasciculus interfascicularis
Lesion in the 1 neuron in a conscious sensory pathway always results in what type of deficits?
Ipsilateral
2 neuron is the one that crosses over
What tract is in charge of unconscious precise proprio of individual muscles in the lower limb?
Dorsal spinocerebellar tract
What tract is in charge of unconscious precise proprio of individual muscles in the upper limb?
Cuneocerebellar tract
What tract is in charge of unconscious gross proprio of individual muscles in the lower limb?
Ventral spinocerebellar tract
