Basic Sensory/Motor tracts

Question 1

What type of reflex is involved in the jaw-jerk and patellar reflexes?

Answer 1

Myotatic reflex (monosynaptic)

Question 2

Main features of a secondary neuron in a conscious sensory pathway?

Answer 2

Decussates, and ascends as a lemniscus -> terminates on tertiary neuron in dorsal thalamus

Question 3

LMNs originate where in the spinal cord?

Answer 3

Anterior horn cells

Question 4

UMNs forms what tract after they decussate?

Answer 4

Lateral Corticospinal tract (decussate at pyramids)-> terminate in LMN pols

Question 5

What are the posterior columns responsible for?

Answer 5

Proprioception and 2-point tactile discrimination

Question 6

The dorsal column/medial lemniscal system carries what kind of information?

Answer 6

Proprioception, 2-point tactile discrimination, vibratory and pressure sensations

Question 7

What carries proprioceptive/2-pt tactile input to UE, and LE, respectively?

Answer 7

fasciculus cuneatus and fasciculus gracilis

Question 8

What type of lesion causes a positive Babinski sign?

Answer 8

UMN lesion

Question 9

What pathway is responsible for fast pain?

Answer 9

Lateral Spinothalamic tract- Sharp, localized pain/temp sensation

Question 10

Contralateral loss of pain/temp sensation 2 sensory dermatomes below lesion indicates what?

Answer 10

Lateral spinothalamic tract lesion

Question 11

Brown-Sequard syndrome is what? Sx?

Answer 11

Hemisection of spinal cord. Results in ipsilateral loss of proprioception/2-pt tactile (posterior columns), ipsilateral spastic paralysis (motor tracts) and contralateral loss of pain/temp sensation 2 sensory dermatomes below lesion (LSTT)

Question 12

Destruction of the anterior white commissure results in what?

Answer 12

B/L loss of pain/temp sensation to UE (yolk-like anesthesia)

Question 13

What makes up the spinal lemniscus?

Answer 13

VSTT (crude tactile) and LSTT (Fast pain/temp)

Question 14

Where do the superior sagittal venous sinus and straight sinuses drain into?

Answer 14

Superior sagittal-> R transverse sinus

Straight sinus-> L transverse sinus

Question 15

What cranial nerves are responsible for taste?

Answer 15

Anterior 2/3= CN5

Posterior 1/3= CN9

Question 16

All U/L lesions of the lateral spinothalamic tract result in what?

Answer 16

Contralateral loss of pain/temp 1-2 segments below lesion

Question 17

What would a U/L lesion of the Spinal lemniscus result in?

Answer 17

Contralateral loss of pain/temp from the body

Question 18

What would a U/L lesion of the medial lemniscus result in?

Answer 18

Contralateral loss of proprioception/2-point tactile discrimination from the body. (remember- lemniscus is in brainstem)

Question 19

Where does the corticospinal tract decussate?

Answer 19

At the pyramids (contralateral hemiplegia if injured above them)

Question 20

Where does the spinothalamic tract decussate?

Answer 20

Anterior white commissure (Injury always contralateral loss of pain/temp)