Spinal Tracts

Front 1

Dorsal Column
cell of origin

Back 1

ipsilateral dorsal root ganglia that alpha-betas; 6 microns
fasciculus gracilis=T7 and below-leg

fasciculus cuneatus=T6 and above (arm

Front 2

Dorsal column
location
pathway

Back 2

dorsal funiculus
pathway: within the dorsal funiculus and in within the medulla the fibers cross over

Front 3

Dorsal column
termination

Back 3

ipsilateral nucleus gracilis and nucleus cuneatus

Front 4

Dorsal column lesion deficit

Back 4

ipsi 2 pt. discrimination, vibration, conscious proprioception, asterognosia, agraphesthesia, ataxia

Front 5

Anterolateral system
cells of origin

Back 5

contralateral dorsal horn
DRG cell types: delta fiber, c fiber

Front 6

Anterolateral system
location and pathway

Back 6

location:anterolateral quadrant of lateral funiculus
pathway: dorsal root fibers enter at zone of lissauer and ascend two levels to synapse onto dorsal horn neurons that cross to reach the anterolateral system

Front 7

Anterolateral system
lesion deficits

Back 7

contralateral loss of pain, temp and crude touch

Front 8

Anterolateral system
termination

Back 8

ipsilateral ventral posterolateral nucleus (VPL) of thalamus

VPL-->somatosensory cortex (areas 3, 1 and 2)

Front 9

Anterolateral system
what happens C2 and C1 since dorsal root fibers need to ascend two levels normally?

Back 9

C2 fibers terminate in spinal nucleus V (part of trigeminal)

C1 has no dorsal root

Front 10

Dorsal Spinocerebellar tract (DCST)
cells of origin (1)

Back 10

medial 1a, II, (muscle spindles) 1b (golgi tendon organs) fibers of dorsal root

Front 11

Dorsal spinocerebellar tract
location of intraspinal cells (2)

Back 11

1a, II, 1b fibers terminate on Clarke's Column (C8-L3 at lamina VII/base of dorsal horn)

fibers reach cerebellum via the dorsolateral part of lateral funiculus

Front 12

Dorsal spinocerebellar tract
termination (3)

Back 12

ipsilateral cerebellum via inferior cerebellar peduncle

Front 13

Dorsal spinocerebellar tract
Lesions

Back 13

ipsilateral muscle incoordination/ataxia

Front 14

dorsal spinocerebellar tract
How do 1a, II, 1b fibers deal with the fact that clarke's column is only C8-L3

Back 14

from below L3-->use fasciculus gracilis until L3 to reach Clarke's

From above C8: enter the cord and ascend within fasciculus cuneatus until they reach the caudal medulla's accessory cuneate nucleus. these cells then project to the ipsi cerebellum like C8-L3 do.

Front 15

Dorsal spinocerebellar tract overview

Back 15

Basically uses two tracts:
C2-C7-fasiculus cuneatus-->accessory cuneatus nucleus in the medulla

C8-L3-uses the dorsal spinocerebellar tract

Front 16

Lateral corticospinal tract (LCST)
cells of origin (1)

Back 16

Corticospinal tract: area 4/precentral gyrus of motor cortex send very long axons that cross at C1 (pyramidal decussation)
Lateral Corticospinal tract fibers (LCST): crossed corticospinal fibers enter lateral funiculus

Front 17

Lateral corticospinal tract
location and course of axons

Back 17

1) pyramid of medulla
2) axons cross at caudal medulla in pyramdial decussation
3) axons enter the lateral funiculus of spinal cord where they comprise lateral corticospinal tract

Front 18

Lateral corticospinal tract
termination

Back 18

ipsilateral (relative to fibers at C1) ventral horn motor neurons

Front 19

Lateral corticospinal tract
Lesion deficits general

Back 19

rostral to pyramidal decussation-contralateral
caudal to pyramidal decussation-ipsilateral

Front 20

Lateral corticospinal tract
Lesion deficits clincally

Back 20

1) ipsilateral muscle weakness-->Hemiplegia
2) spasticity (seen when passively moving muscle)
3)clonus: hyperreflexia
4) Babinski sign

Front 21

Lateral corticospinal tract
reflexes effected

Back 21

1) cutaneomuscular abdominal and cremasteric reflexes
2) Babinkski sign present
3) Chaddock sign
4) Bing Sign
5) Hoffman sign
6) loss of cremasteric reflex

Front 22

ventral horn cells

Back 22

lower motor neurons

Front 23

axial muscles

Back 23

motor neurons are medial to those controlling distal muscles

Front 24

flexors versus extensors

Back 24

flexors lie dorsal to those controlling extensors

Front 25

T1 and below

Back 25

LMNs are associated with axial musculature

Front 26

Lesions in LMNs

Back 26

atrophy, flaccidity, atonicity and areflexia

Front 27

LCST and LMN relationship

Back 27

Upper motor neuron pathway (LCST) synapses onto LMNs

Front 28

Lesion in UMN

Back 28

spasticisity, but no atrophy

Front 29

Spinal shock

Back 29

acute: atonia and flacidity below levels of lesion, chronic: weakness and spasticity

Front 30

Lateral Horn: cells of origin

Back 30

1) preganglionic sympathetic cells from T1-L2, 2) hypothalamus

Front 31

Lateral Horn: location

Back 31

lateral cell column axons pass through white communicating rami

Front 32

Lateral Horn: options of preganglionic fibers

Back 32

1) synapse within paravertebral ganglia, 2) ascend or descend, 3) exit to become splanchnics

Front 33

Lateral Horn: termination

Back 33

T1 to T5 ascend to superior cervical ganglion

Front 34

Lateral horn: lesions

Back 34

1) Horners- T1 lesion, 2) T1-L2-loss of sweating in area of deinnervation, 3) C1 to T1-loss of sweating over entire body ipsilateral to lesion