Spinal Pathways Flashcards
Where is the primary somatosensory cortex?
Post central gyrus
What are the main sensory pathways?
Dorsal Column/Medial Lemniscus System
Spinothalamic Tract
What is conveyed by the DCMLS?
Fine touch
Conscious proprioception
What is conveyed by the STT?
Pain
Temperature
Deep pressure
Where do the neurones in the DCMLS enter?
Lumbar level (lower limb) Cervical level (upper limb)
Where do the neurones in the DCMLS cross?
Medulla
Where do the neurones in the DCMLS synapse?
1) Lower limb - nucleus gracilis in medulla, Upper limb - nucleus cuneaus in medulla
2) VP thalamus
3) Sensory cortex
Where do the neurones in the STT cross over?
Segmentally (immediately after first synapse at level of spinal cord entrance)
Where do the neurones in the STT synapse?
On entering the spinal cord (before crossing over)
Thalamus
Sensory cortex
Where is the primary motor cortex?
Pre central gyrus
What are the main motor pathways?
PYRAMIDAL TRACT
Corticospinal tract
EXTRAPYRAMIDAL TRACTS
Tectospinal tract
Reticulospinal tract
Vestibulospinal tract
What is conveyed by the CST?
Fine, precise movement (esp at distal limb muscles)
Why is the CST often referred to as the pyramidal tract?
Tract forms visible ridges in the medulla which look like pyramids
Where do the neurones in the CST cross over?
85% in caudal medulla at desiccation of pyramids = lateral CST
Rest cross segmentally = medial CST
What is mediated by the Tectospinal tract?
Reflex head and neck movements
