NeuroAnatomy AND NeuroPathology Lecture 11 Objectives - Spinal Cord

Question 1

Where does conus medullaris terminate in the vertebral column?

Answer 1

T12 / L1

Question 2

What is the lumbar cistern?

Answer 2

enlargement of the subarachnoid space distal to conus medullaris containing CSF + cauda equina

Question 3

What is the difference between the filum terminale interna vs externa?

Answer 3

Interna = continuation of pia mater that extends to the bottom of the lumbar cistern // Externa = continuation of dura mater that extends to coccyx

Question 4

What are the dentate ligaments?

Answer 4

pia mater extensions that anchor the spinal cord to the arachnoid and dura layers

Question 5

What type of information do dorsal nerve roots carry?

Answer 5

sensory input from peripheral nerves

Question 6

What type of information do ventral nerve roots carry?

Answer 6

motor output to peripheral nerves

Question 7

Do dorsal nerve roots connect to the anterior or posterior horn?

Answer 7

Posterior horn of spinal cord

Question 8

Do ventral nerve roots connect to the anterior or posterior horn?

Answer 8

anterior horn of spinal cord

Question 9

If the anterior horn is damaged / the ventral nerve roots, does that result in an UMNL or LMNL?

Answer 9

LMNL

Question 10

As a refresher, what are the signs/symptoms of a LMNL?

Answer 10

hypotonia, hyporeflexia, flaccid paralysis, quick atrophy

Question 11

Are the sensory tracts in the white matter ascending or descending?

Answer 11

they are ascending tracts from the body up to the brain

Question 12

Are the motor tracts in the white matter ascending or descending?

Answer 12

they are descending tracts from the brain to the muscles of the body

Question 13

What are the three columns of white matter?

Answer 13

Posterior/Dorsal column, Lateral column, and Anterior/Ventral column

Question 14

What does the Anterior Spinal Artery supply?

Answer 14

anterior 2/3 of spinal cord // anterior and lateral columns

Question 15

What does the Posterior Spinal Arteries (R/L) supply?

Answer 15

posterior 1/3 of spinal cord // posterior columns

Question 16

What are all of the 6 descending motor tracts?

Answer 16

Lateral / Anteriomedial Corticospinal tracts, Rubrospinal tract, Tectospinal tract, Reticulospinal tract, and Vestibulospinal tract

Question 17

What is the function of the Lateral Corticospinal Tract?

Answer 17

Controls fine motor movement of distal extremities

Question 18

Where does the Lateral Corticospinal Tract originate?

Answer 18

Primary Motor Cortex

Question 19

Where does the Lateral Corticospinal Tract cross?

Answer 19

Pyramidal Decussation

Question 20

Where does the Lateral Corticospinal Tract terminate?

Answer 20

anterior horn motor neurons supplying the UE/LE muscles

Question 21

What symptoms would you expect if there was a lesion ABOVE the medulla for the Lateral Corticospinal Tract?

Answer 21

Above the medulla = before it crosses midline // symptoms would be contralateral hemiparesis

Question 22

What symptoms would you expect if there was a lesion BELOW the medulla for the Lateral Corticospinal Tract?

Answer 22

Below the medulla = after it crosses midline // symptoms would be ipsilateral hemiparesis

Question 23

What is the function of the Rubrospinal Tract?

Answer 23

Supportive role of LCT // promotes UE flexors and inhibits UE extensors

Question 24

Where does the Rubrospinal Tract originate?

Answer 24

Red nucleus in midbrain

Question 25

Where does the Rubrospinal Tract cross?

Answer 25

It crosses immediately

Question 26

Where does the Rubrospinal Tract terminate?

Answer 26

anterior horn motor neurons supplying the UE/LE muscles

Question 27

What are signs/symptoms of a lesion in the Rubrospinal tract?

Answer 27

lesions to this tract alone is rare and would involve the LCT // lesions involving the red nucleus would cause deceberate/decorticate posturing

Question 28

What is Decorticate posturing?

Answer 28

brainstem damage to red nucleus and structures “above” it // leading to excessive flexor tone in UE

Question 29

What is Deceberate posturing?

Answer 29

brainstem damage to red nucleus and structures “below” // leading to UE extensor tone and is considered more severe than decorticate

Question 30

What is the function of the Anteriomedial Corticospinal Tract?

Answer 30

control/maintain axial and proximal limb voluntary movement // works synergistically with LCT

Question 31

Where does the Anteriomedial Corticospinal Tract originate?

Answer 31

Primary Motor Cortex

Question 32

Where does the Anteriomedial Corticospinal Tract cross?

Answer 32

It does not

Question 33

Where does the Anteriomedial Corticospinal Tract terminate?

Answer 33

near ventral horn of most levels of spinal cord

Question 34

What are signs/symptoms of a lesion in the Anteriomedial Corticospinal Tract?

Answer 34

Depending on where the lesion is in the spinal cord - ipsilateral hemiparesis

Question 35

Neuropathic pain can be a result of a dysfunction in which of the previously mentioned spinal tracts?

Answer 35

spinothalamic tract

Question 36

In nociceptive pathways, what are the two fibers?

Answer 36

A Delta fibers – myelinated and fast transmission
C fibers – unmyelinated and slow transmission

Question 37

In the spinal cord, where does nociceptive information enter, cross, and ascend?

Answer 37

enter in the posterior horn, crosses immediately, ascends in the anterolateral spinothalamic tract

Question 38

What is the pathway for the A Delta fibers for nociception?

Answer 38

enters posterior horn, crosses immediately, lands in lateral spinothalamic tract, ascending to thalamus and primary somatosensory cortex

Question 39

What is the pathway for the C fibers for nociception?

Answer 39

enters posterior horn, crosses immediately, lands in anterior spinothalamic tract, ascending to thalamus and terminating in different areas of the brain