Spinal Cord Slices

Front 1

Back 1

anterior funiculus

- contains tracts of the medial descending system

- reticulospinal tracts

- vestibulospinal tracts

- anterior corticospinal tract

- controls posture and balance

Front 2

Back 2

lateral funiculus

Front 3

Back 3

posterior funiculus

Front 4

Back 4

fasciculus gracilis

Front 5

Back 5

fasciculus cuneatus

- only present T6 and above

Front 6

Back 6

anterior white commissure

- fibers carrying pain, temp, light touch cross (from the zone of lissauer)

Front 7

Back 7

zone of lissauer

- primary afferents of anterolateral spinothalamic system (pain, temp, light touch)

Front 8

Back 8

ventral horn

Front 9

Back 9

dorsal horn

Front 10

Back 10

dorsal roots

- damage = disruption of afferent limb of myotatic reflex

Front 11

Back 11

ventral roots

- damage = reduced myotatic reflexes in efferent limb muscles

Front 12

Back 12

alpha-motor neurons in ventral horn

- associated with lower motor neurons, so peripheral

LMNs damage = atrophy, reduced reflexes

Front 13

Back 13

lateral horn (upper thoracic spinal cord)

- aka intermediallateral nucleus (IML)

- contains sympathetic preganglionic neurons of CNS (

- most synapse in sympathetic trunk via white rami communicantes

Front 14

Back 14

dorsal nucleus of clarke (upper thoracic section)

- posterior spinocerebellar tract originates here

- ascends ipsilaterally to cerebellum

- proprioceptive inputs from muscles/joints in lower limb

Front 15

Back 15

substantia gelatinosa (rexed's lamina II) (upper thoracic section)

- contains inhibitory neurons to mediate pain

- rubbing skin activates mylinated fibers in posterior column that activate inhibitory interneurons, which synapse on ALSTT neurons to reduce pain (gate theory of pain)

Front 16

all

Back 16

yellow= fasciculus gracilis

orange= anterolateral spinothalamic tract

green= posterior spinocerebellar tract

red= lateral corticospinal tract

purple= fasciculus cuneatus

blue= anterior spinocerebellar tract

white= descending autonomic fibers

Front 17

yellow

Back 17

fasciculus gracilis

- T7 and below (leg and lower trunk)

- terminates in nucleus gracilis in medulla

- degeneration = vitamin B12 deficiency

- tacticle discrimination, vibration, pressure, conscious proprioception

- large diameter, myelinated, primary afferent axons; enters dorsal roots; ascend ipsilaterally in posterior columns

Front 18

orange

Back 18

anterolateral spinothalamic tract

- crosses in anterior white commissure, so damage affects contralateral side below lesion

- damage = loss of pain and thermal sensation (touch is not affected b/c it has redundancy)`

Front 19

green

Back 19

posterior spinocerebellar tract

- unconscious proprioception

Front 20

red

Back 20

lateral corticospinal tract

- pyramidal decussation (spinomedulary junction), so damage below medulla = ipsilateral

- upper motor neuron

- damage = weakness (spasticity)

- symptoms: Babinski sign, increased resistance to passive stretch, hypertonia, hyperflexia

Front 21

purple

Back 21

fasciculus cuneatus

- T6 and above (upper trunk, upper limb, neck)

- terminates in nucleus cuneatus in medulla

- tacticle discrimination, vibration, pressure, conscious proprioception- large diameter, myelinated, primary afferent axons; enters dorsal roots; ascend ipsilaterally in posterior columns

Front 22

blue

Back 22

anterior spinocerebellar tract

- unconscious proprioception

Front 23

white

Back 23

descending autonomic fibers

- synapse in ipsilateral intermediolateral nucleus

- originates in hypothalamus and brainstem

- controls sympathetic neurons in IML

- damage = constriction of ipsilateral pupil (Horner's syndrome)