Spinal Tracts - Lab Edition

Question 1

tracts in dorsal column medial lemniscus?

Answer 1

fasciculus gracilis and fasciculus cuneatus

Question 2

Fasciculus gracilis tract function?

Answer 2

LE light touch and conscious proprioception

Question 3

Fasciculus cuneatus tract function?

Answer 3

UE light touch and conscious proprioception

Question 4

Dorsal column medial lemniscus:
- 1st order neuron cell body?
- 2nd order neuron cell body?
- 3rd order neuron cell body?

Answer 4

• dorsal root ganglion
• nucleus gracilis/cuneatus
• thalamus

Question 5

DCML: Fasciculus gracilis

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 5

• comes from LE to the dorsal horn
• from dorsal horn to medulla nucleus gracilis where it crosses in the internal arcuate fibers
• after crossing in medulla it travels to the thalamus (axons form part of the internal capsule (forebrain)) then to the primary somatosensory cortex (more medial bc legs)

Question 6

DCML: Fasciculus Cuneatus

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 6

• comes from UE to the dorsal horn
• from dorsal horn to medulla nucleus cuneatus where it crosses in the internal arcuate fibers
• after crossing in medulla it travels to the thalamus (axons form part of the internal capsule (forebrain)) then to the primary somatosensory cortex (more lateral)

Question 7

anterolateral system tracts?

Answer 7

lateral spinothalamic tract and anterior spinothalamic tract

Question 8

lateral spinothalamic tract function?

Answer 8

fast nociception and temperature (conscious)

Question 9

anterior spinothalamic tract function?

Answer 9

crude touch (conscious)

Question 10

Anterolateral system: Lateral spinothalamic tract

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 10

• comes from anywhere in the body to dorsal horn
• crosses at that level through the anterior commissure –> ascending through the lateral ST tract to thalamus
• thalamus thru internal capsule to primary and secondary association somatosensory cortices

Question 11

Anterolateral system: Anterior Spinothalamic

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 11

• comes from anywhere in the body to dorsal horn
• crosses at that level through the anterior commissure –> ascending through the ventral spinothalamic tract to thalamus
• thalamus thru internal capsule to primary and secondary association somatosensory cortices

Question 12

Tracts of the medial group?

Answer 12

medial (ventral) corticospinal tract and reticulospinal tract

Question 13

medial (ventral) corticospinal tract function?

Answer 13

UNCROSSED

• automatic trunk and proximal movements; postural and gross/proximal/axial movements

(premotor cortex bc automatic movements)

Question 14

reticulospinal tract function?

Answer 14

UNCROSSED

• postural and gross limb movements; coordinates trunk and muscles of 4 limbs for walking

Question 15

Medial (ventral) corticospinal tract:

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 15

• originates from premotor cortex through the internal capsule and cerebral peduncle and anterior brainstem
• descends in medial funiculus of SC
• synapses on interneurons or MNs in medial motor nuclei of ventral horn

DOES NOT CROSS

Question 16

Reticulospinal tract:

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 16

• originates from brainstem and descends thru medial longitudinal fasciculus
• synapse with medial motor nuclei of ventral horn of the associated level

UNCROSSED

Question 17

tracts of lateral group?

Answer 17

Rubrospinal tract and lateral corticospinal tract

Question 18

lateral corticospinal tract function?

Answer 18

fractionated movements; voluntary distal limb movements (fractionated because it is an inhibitory pathway)

80-90% of all CST fibers

Question 19

rubrospinal tract function?

Answer 19

fractionated movements of UE distal extensors (fractionated because it is an inhibitory pathway)

Question 20

Rubrospinal tract:

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 20

• originates in red nucleus (in midbrain)
• crosses at ventral tegmental decussation in midbrain
• descends through the rubrospinal tract in the lateral column
• synapse ventral horn of associated levels in the lateral motor nuclei

Question 21

Lateral corticospinal tract:

• where does it originally come from?
• where does it cross?
• where does it go after crossing/to finish?

Answer 21

• originates from the primary motor cortex through the internal capsule and cerebral peduncle and lateral posterior brainstem
• crosses at the pyramidal decussation in medulla
• descends in the lateral funiculus of SC
• synapses on interneurons or MNs in lateral motor nuclei of ventral horn

Question 22

tracts of the pyramidal tract?

Answer 22

corticbrainstem/corticobulbar tract

Question 23

Corticobulbar/corticobrainstem tract function?

Answer 23

facial movements