Posterior Column-Medial Lemniscus pathway (PCML) & Trigem. Nuclei Flashcards
What does the PCML pathway transmit?
Somatosensory - touch (texture, size, shape), tactile information and proprioception
What is proprioception?
Knowing where your body is in space without seeing
Primary afferent fibers
Sensory fibers
Where do primary afferent fibers enter the spinal cord?
Medial division of posterior root
What do the afferent fibers ascend as?
Posterior column
Posterior column - grey or white matter?
White
Afferent fibers from sacral level - T6 go where in the posterior column?
Fasciculus Gracilis
Afferent fibers from T6 - superior go where in the posterior column?
Fasciculus cuneatus
Where is the fasciculus gracilis?
Medial side of posterior column
Where is the fasciculus cuneatus?
Lateral side of posterior column
Afferent fibers from ex. T9 will go to what side of the posterior column?
Medial
Afferent fibers from ex. T3 will go to what side of the posterior column?
Lateral
What will lesions in the posterior column produce?
IPSILATERAL sensation loss at and below affected segment
What is sensory ataxia?
Loss of reflexes and proprioception from extremities due to lack of sensory input
How may a patient with sensory ataxia stand?
With a wide base to try and reestablish the proprioception
If the fibers run in the fasciculus gracilis, where will they synapse?
Gracile nucleus
If the fibers run in the fasciculus cuneatus, where will they synapse?
Cuneate nucleus