Lesion Principles

Question 1

What are some pathway principles?

Answer 1

1. Most things are represented backwards and upside down from the body parts they control.(Except for the cerebellum)
2. If a structure has the word ‘anterior’ or ‘ventral’ in it, its involved in motor function.
3. If a structure has the word ‘posterior’ or ‘dorsal’ in it, its involved in sensory
4. Once a pathway crosses it will stay on that side until it gets to its destination

Question 2

Discuss the pyramidal system aka Corticospinal tract

Answer 2

1. Carries signal for initiating movement from motor cortex (voluntary)
2. Cross at lowest part of medulla
3. Involvement of this system causes UMN lesion.

Question 3

Discuss the Corticobulbar Tract

Answer 3

1. Crosses the brainstem and close to the cranial nerve it supplies.

Question 4

Discuss the Spinothalmic tract

Answer 4

1. Carries sensory from lateral spinal cord to opposite thalamus.
2. Carries temp, pain and touch; crosses spinal cord almost immediately.
3. After the thalamus, relay signals enter parietal lobe contralateral to the side of the body thats represented.

Question 5

Discuss the Trigeminal system

Answer 5

Carries sensory info from the face to the thalamus, on the way to the parietal lobe.

Question 6

Discuss the Dorsal column-medial lemniscal system

Answer 6

Carries Motion, vibration and position from posterior spinal cord to the opposite thalamus. Crosses at lower medulla