Spinal tract anatomy and functions

Question 1

Dorsal column

Answer 1

Ascending: pressure,
vibration, fine touch,
and proprioception

Question 2

Dorsal column 1st order neuron

Answer 2

Sensory nerve ending
--> cell body in dorsal root
ganglion --> enters spinal
cord, ascends ipsilaterally in
dorsal column

Question 3

Dorsal column 1st synapse

Answer 3

Ipsilateral nucleus cuneatus or gracilis (medulla)

Question 4

Dorsal column 2nd order neuron

Answer 4

Decussates in medulla –> ascends contralaterally in medial lemniscus

Question 5

Dorsal column 2nd synapse

Answer 5

VPL (thalamus)

Question 6

Dorsal column 3rd order neuron

Answer 6

Sensory cortex

Question 7

Spinothalamic tract

Answer 7

Ascending. lateral: pain, temperature; anterior: crude touch, pressure

Question 8

Spinothalamic tract 1st order neuron

Answer 8

Sensory nerve ending (A-delta and C fibers) (cell body in dorsal root ganglion) –> enters spinal cord

Question 9

Spinothalamic tract 1st synapse

Answer 9

Ipsilateral gray matter (spinal cord)

Question 10

Spinothalamic tract 2nd order neuron

Answer 10

Decussates at anterior commisure –> ascends contralaterally

Question 11

Spinothalamic tract 2nd synapse

Answer 11

VPL (thalamus)

Question 12

Spinothalamic tract 3rd order neuron

Answer 12

Sensory cortex

Question 13

Lateral corticospinal tract

Answer 13

Descending: voluntary movement of contralateral limbs

Question 14

Lateral corticospinal tract 1st order neuron

Answer 14

UMN: cell body in primary motor cortex –> descends ipsilaterally (through internal capsule), most fibers decussate at caudal medulla (pyramidal decussation) –> descends contralaterally

Question 15

Lateral corticospinal tract 1st Synapse

Answer 15

Cell body of anterior horn (spinal cord)

Question 16

Lateral corticospinal tract 2nd order neuron

Answer 16

LMN: leaves spinal cord

Question 17

Lateral corticospinal tract 2nd synapse

Answer 17

Neuromuscular junction