Sarko- Spinal Cord

Question 1

Corticospinal pathway

Beginning, decussation, termination, lesion presentation

Answer 1

Beginning: Cortex
Decussation: Medullary pyramid (becoming lateral corticospinal tract)
Synapses at the ventral horn
Termination: The muscle
Lesion: UMN=hyperreflexia, LMN=hyporeflexia

Question 2

Spinothalamic Pathway (Beginning, decussation, termination, lesion presentation)

Answer 2

Beginning: Pain/temperature afferent neuron, whose body is in the dorsal horn

Decussation: 2nd order neuron decussates at the level through ventral white commissure (ascends as the spinothalamic tract)

Terminates: Cortex (S1/primary somatosensory cortex/postcentral gyrus)

Lesion: Temperature/pain loss at that level

Question 3

Syringomyelia

Answer 3

CSF-filled cyst that compresses the surrounding white matter, but only the spinothalamic tract (DCML/PCML is intact)

Question 4

PCML/DCML pathway (Beginning, decussation, termination, lesion presentation)

Answer 4

Beginning: Afferent neuron, whose cell body is in the dorsal root ganglion
Decussation: Second-order neuron decussates at the level of the caudal medulla in the brain as the internal arcuate fiber
Terminate: Primary somatosensory cortex (S1, or postcentral gyrus)
Lesion: Numbness, loss of fine touch discrimination/sensation etc.

Question 5

2 main sources of arteries in the spinal cord

Answer 5

Vertebral arteries: give rise to 3 spinal arteries (1 anterior and 2 posterior, which run the length of the spinal cord)

Radicular arteries

Question 6

Functions of rubrospinal pathway

Answer 6

Descending motor

Facilitate lateral corticospinal system, impose cerebellar influence on motor activity

Dedicated to the flexors of the upper limb

Question 7

Tectospinal Pathway

Answer 7

Descending motor

Coordination of head and eye movements to enable orientation movements; generates saccades (rapid eye movement between two points)

Question 8

Reticulospinal Pathway

Answer 8

Descending motor

Maintain posture
Anticipatory; role in muscle tone

Medial reticulospinal tract originates in the pons, lateral reticulospinal tract originates in the medulla

Travels ipsilaterally through reticulospinal tracts