Lab 7 Descending Tracts

Question 1

Lateral Corticospinal Tract

Answer 1

• Dorsolateral Pathway
• Contralateral (Crosses in Pyramidal Decussation)
• Serves limb muscles
• Enables fractionation of movement
• Control of fine movement of contralateral UE/LE
• Modulate Sensory info

Question 2

Rubrospinal Tract

Answer 2

• Dorsolateral Pathway
• Contralateral (Crosses Immediately)
• Facilitate MN that innervate large muscle movements and fine motor control
• Primarily serves CERVICAL regions
• Greater influence on FLEXOR muscles
• INHIBITS EXTENSORS

Question 3

Medial Vestibulospinal Tract

Answer 3

• Ventromedial Pathway
• Primarily Ipsilateral
• Activates LMN associated with spinal accessory n:
  
  1. Rotation/Lifting of head and shoulder blade
  2. Movements appropriate for orientation of individual during altered posture and balance

Question 4

Lateral Vestibulospinal Tract

Answer 4

• Ventromedial Pathway
• Ipsilateral
• Important for maintenance of upright posture and balance via excitation of antigravity/extensor muscles (mainly of trunk and ipsilateral limb)

Question 5

Tectospinal Tract

Answer 5

• Ventromedial Pathway
• Contralateral (Crosses immediately via Posterior Tegmental Decussation)
• Directs head movements in response to visual stimuli

Question 6

Lateral Reticulospinal Tract

Answer 6

• Ventromedial Pathway
• Originates in MEDIAL 2/3 of MEDULLA
• Coordinates trunk/proximal muscle response during limb movements by SUPPRESSING EXTENSOR ACTIVITY

Question 7

Medial Reticulospinal Tract

Answer 7

• Ventromedial Pathway
• Originates in PONS
• Coordinates trunk/proximal muscle response during limb movements by FACILITATING EXTENSOR ACTIVITY