02 Spinal Cord Internal Structure I

Front 1

What is rexed's laminae

Back 1

Front 2

What are the nuclei of the posterior (dorsal) horn of the grey matter. What type of nuclei are they

Back 2

-Substantia gelatinosa of rolandi (SGR)

-Nucleus proprius

-Clark's Dorsal Nucleus

These are sensory nuclei

Front 3

Give the afferent, efferent and crossing of the SGR

Back 3

Afferent: pain and temp via central processes of dorsal root ganglion cells

Efferent: axons cross opposite in white commissure and ascend in lateral column white matter

Crossing: These do cross. Lateral spinothalamic tract

Front 4

Give the afferent, efferent and crossing of the Nucleus proprius

Back 4

Afferent: light pressure and crude touch via central processes of dorsal root ganglion cells

Efferent: axons cross opposite side in white commissure and ascend in anterior white matter

Crossing: These do cross. Anterior spinothalamic tract

Front 5

Give the afferent, efferent and crossing of Clark's dorsal nucleus

Back 5

Afferent: proprioception via collaterals from fibers in posterior column white matter

Efferent: axons ascend without crossing in the lateral column of the same side

Crossing: No crossing. Posterior spinocerebellar tract

Front 6

What are the nuclei of the anterior horn

Back 6

Medial group: anteromedial and posteromedial

Lateral group: anterolateral and posterolateral

Central group (only in cervical)

Front 7

Give the afferent and efferent of the Medial group

Back 7

Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc

Efferent: innervate axial trunk muscles

Front 8

Give the afferent and efferent of the lateral group

Back 8

Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc

Efferent: innervate muscles of upper and lower limbs

Front 9

Give the afferent and efferent of the central group

Back 9

Afferent: pyramidal, extra pyramidal, proprioceptive impulse from muscles, short associative tracts for reflex arc

Efferent: runs in phrenic nerve to diaphragm, spinal accessory supplies trapezius and sternocleidomastoid

Front 10

What are the nuclei of the lateral horn

Back 10

Sympathetic: Lateral horns T1-L2/L3

Parasympathetic: Lateral Horns S2-S4

(lateral horn is the blue dotted area from previous pictures)

Front 11

Give the afferent and efferent of

Sympathetic: Lateral horns T1-L2/L3

Back 11

Afferent: descending autonomic fibers from higher centers in hypothalamus and higher centers in brain and brainstem

Efferent:Axons leave cord in ventral roots of spinal nerves as preganglionic fibers to relay in corresponding ganglia of sympathetic chain

Front 12

Give the afferent and efferent of Parasympathetic: Lateral Horns S2-S4

Back 12

Afferent: descending autonomic fibers from higher centers in hypothalamus and higher centers in brain and brainstem

Efferent:Axons leave cord in ventral roots of spinal nerves as preganglionic fibers to relay on terminal ganglia

Front 13

Describe the lamination of the white matter in the anterolateral system

Back 13

Anterolateral system is arranged leg-trunk-arm-neck, in that order from superficial to deep explaining why lesions exerting sustained gradual pressure will cause loss of pain and temperature in sacral dermatomes before higher segments.

Front 14

What do the Gracile fascicles (tract) and Cuneate fascicles (tract) of the posterior column contain

Back 14

Gracile: leg and lower trunk

Cuneate: upper trunk, arm, neck, occiput

Front 15

Describe the clinical significance of the layout of the posterior column

Back 15

Because the posterior column is ordered leg-lower trunk-upper trunk-arm-neck-occiput from medial to lateral that means the cervical dermatomes will be affected first and sacral one last with sustained external pressure

Front 16

What are the Ascending and Descending Tracts of the posterior (dorsal) column

Back 16

Ascending: gracile and cuneate

Descending: none

Front 17

What are the Ascending and Descending Tracts of the Anterior (ventral) column

Back 17

Ascending: anterior spinothalamic (aka anterolateral system)

Descending Tracts: Anterior corticospinal, tectospinal, vestibulospinal (medial vestibulospinal tract), reticulospinal (medullary and pontine reticulospinal)

Front 18

What are the Ascending and Descending Tracts of the Lateral column

Back 18

Ascending: lateral spinothalamic (part of anterolateral system), Dorsal and ventral spinocerebellar,

Descending: lateral corticospinal, rubrospinal, It also says there is a lateral tectospinal but I don't see it.

Front 19

Back 19

Front 20

Which tracts carry conscious sensations

Back 20

gracile

cuneate

lateral spinothalamic

ventral spinothalamic

Front 21

Describe the sensation carried, origin and termination of the gracile tract

Back 21

Sensation: proprioception and fine touch from LOWER 1/2 (gracile has an L in it) of body

Origin: cells of dorsal root ganglion central process pass in dorsal root and ascend in the dorsal column

Termination: gracile nucleus in closed medulla

Front 22

Describe the sensation carried, origin and termination of the Cuneate tract

Back 22

Sensation: proprioception and fine touch from UPPER 1/2 (cuneate has a U in it) of body

Origin: cells of dorsal root ganglion central process pass in dorsal root and ascend in the dorsal column

Termination: cuneate nucleus in closed medulla

Front 23

Describe the sensation carried, origin and termination of the lateral spinothalamic tract

Back 23

Sensation: pain and temp from contralateral side below the head

Origin: axons of the SGR cross in front of the central canal

Termination: posterolateral ventral nucleus of thalamus (PLVN)

Front 24

Describe the sensation carried, origin and termination of the anterior spinothalamic tract

Back 24

Sensation: crude touch and light pressure from contralateral side below the head

Origin: axons of the nucleus proprius cross

Termination: PLVN of thalamus

Front 25

Which tracts carry unconscious sensation

Back 25

dorsal (posterior) spinocerebellar

Ventral (anterior) spinocerebellar

Spinoolivary

spinotectal

Front 26

Describe the sensation carried, origin and termination of the dorsal (posterior) spinocerebellar tract

Back 26

Sensation: proprioception from trunk and lower limb to cerebellum

Origin: Axons of Clark nucleus to the SAME side

Termination: Ascend to cerebellum of the same side

Front 27

Describe the sensation carried, origin and termination of the Ventral (anterior) spinocerebellar tract

Back 27

Sensation: proprioception from lower limb to cerebellum

Origin: axons of cells at base of posterior horn cross to the opposite side

Termination: ascend to the midbrain and then RECROSS to cerebellum of the SAME side

Front 28

Describe the sensation carried, origin and termination of the olivary tract

Back 28

Sensation: proprioception to olivary nucleus of medulla

Origin: axons of large cells at base of posterior horn cross to the opposite side

Termination: inferior olivary nucleus to cerebellum via olivo cerebellar fibers

Front 29

Describe the sensation carried, origin and termination of the spinotectal tract

Back 29

Sensation: pain, temp, touch to tectum of midbrain (carry spino-visual reflexes)

Origin: axons of cells at posterior horn cross to the opposite side

Termination: superior colliculus of the tectum of the midbrain.

Front 30

What are the two types of conscious sensations

Back 30

exteroceptive: from skin (pain, temp, touch)

enteroceptive: from muscles, joints, ligaments and fascia (position, passive movement and vibration)

Front 31

Where must all conscious sensation reach

Back 31

The sensory area in the post central gyrus

Front 32

The sensory area of each cerebral hemisphere receives sensation from where

Back 32

The opposite half of the body

Front 33

Every sensation is transmitted from the receptors to the sensory area by ___ neurons

Back 33

3 neurons

Front 34

Where does all sensation lie for the first order neuron

Back 34

all sensation lies in the dorsal root ganglion

Front 35

Define and describe the processes of the first order neuron

Back 35

peripheral process receives sensation from the receptors

Central process trasmits sensation to the second order neuron

Front 36

What are the two possible locations of the second order neuron? In what types of sensation is each used

Back 36

spinal cord: pain, temp, touch

Medulla: proprioception and fine touch

Front 37

What must second order neurons do to reach the thalamus

Back 37

Second order neurons must cross the midline to reach the thalamus of the opposite side

Front 38

Where is the third order neuron located

Back 38

for all sensations the third order neuron is in the posterolateral ventral nucleus of the thalamus (PLVNT) on the OPPOSITE side

Front 39

Where do axons of the cells in the pLVNT transmit sensation to

Back 39

The sensory area in the post central gyrus.

Front 40

What are the possible lesions if a patient presents with sensory loss on the contralateral side

Back 40

lesion could be in:

-the sensory area of the cerebral cortex

-third order neuron in the thalamus

-leminscus (ascending axons of second order neurons after they have crossed)

Front 41

What are the possible lesions if a patient presents with sensory loss on the ipsilateral side

Back 41

lesion is in the first order neuron

Front 42

What are the afferent sensory fiber types

Back 42

general somatic sensory (GSS): exteroceptive and enteroceptive to CNS

General visceral sensory (GVS): viscera to CNS

special somatic sensory (SSS): ear and eye to CNS

Special visceral sensory (SVS): taste and smell to CNS

Front 43

What are the efferent motor fibers

Back 43

General somatic motor (GSM): CNS to striated muscle

General Visceral Motor (GVM): CNS to smooth muscle, heart and glands

Special visceral motor (SVM): CNS to special visceral muscles

Front 44

Describe the pathway of the first order neuron for vibration, proprioception and fine touch

Back 44

through the dorsal root ganglia the central process enters the spinal cord and ascends in the posterior column in the gracile (lower 1/2) or cuneate (upper 1/2)

Front 45

Describe the pathway of the second order neuron for vibration, proprioception and fine touch

Back 45

The gracile or cuneate nuclei in the medulla. Their axons form internal arcuate fibers which cross in the medulla and then ascend on the opposite side as the medial lemniscus. The medial lemniscus ascends to end in posterolateral ventral nucleus of the thalamus (PLVNT)

Front 46

Describe the pathway of the third order neuron for vibration, proprioception and fine touch

Back 46

posterolateral ventral nucleus of the thalamus (PLVNT). The axons of these cells ascend as sensory radiation. They pass in the posterior half of the posterior limb of the internal capsule to reach the post central gyrus

Front 47

What diagnosis would you be considering if a patient presents with loss of proprioception (sensory ataxia) manifested by high stepping and unsteady gait?

Back 47

Tabes dorsalis: a syphilitic lesions in the dorsal column

Front 48

Describe the first order neuron for pain and temp below the head

Back 48

From the dorsal root ganglia the central processes enters the spinal cord and ascends or descends for one segment before relaying in the substantial gelatinous of rolandi which then forms Lissauer's tract

Front 49

Describe the second order neuron for pain and temp below the head

Back 49

From the substantial gelatinous of rolandi these axons cross to the opposite side and ascend as the lateral spinothalamic tract and ascends through the brainstem together with the ventral spinothalamic tract forming the spinal lemniscus which then ascend to end in the PLVNT (posterolateral ventral nucleus of the thalamus)

Front 50

Describe the third order neuron for pain and temp below the head

Back 50

from PLVNT these axons ascend as sensory radiation. They pass in the posterior half of the posterior limb of the internal capsule to reach the post central gyrus

Front 51

Define and describe a syringomyelia

Back 51

lateral spinothalamic tract lesion: enlargement in the central canal of the spinal cord due to fusion of the central canal with cysts in the grey matter surrounding it (hydromyelia). The second order neuron of pain and temp are affected as they cross in front of the central canal causing selective loss of pain and temp but light touch and proprioception are preserved. This is termed dissociated sensory loss.

Front 52

Describe the differences between pain and temp vs crude touch below the head.

Back 52

Crude touch: second order neuron is nucleus proprius and they cross at the same level instead of one above or below. After crossing they ascend in the anterior spinothalamic tract. Rest is the same.

Front 53

Pain is going to go to the cortex for processing in one of five areas. What are these five areas and what do they each uniquely do.

Back 53

1.somatosensory cortex: conscious recognition, appreciation, analysis, localization and previous experience.

2. cingulate gyrus: emotional

3. insular cortex: autonomic response (sweating)

4. reticular formation of brain stem to alert the cerebral cortex

5. intralaminar nuclei of thalamus to alert the cerebral cortex (yes, same as 4)

Front 54

what is the pathway for sensation from the head

Back 54

The trigeminal pathway

Front 55

The trigeminal ganglion splits into three nuclei. What are the nuclei and what are their functions? Which order neurons are these

Back 55

1. main sensory nucleus: crude touch

2. Spinal nucleus: pain and temp

3. mesencephalic nucleus: proprioception and fine touch

First order neurons

Front 56

Describe the second order neurons of the trigeminal pathway (sensation from head)

Back 56

Axons of the three trigeminal nuclei cross to the opposite side and ascend as the trigeminal lemniscus and ascends through the brainstem to the PMVNT

Front 57

Describe the third order neurons of the trigeminal pathway

Back 57

PMVNT axons ascend in the posterior limb of the internal capsule to reach the post central gyrus

Front 58

Describe posterior cord syndrome and anterior cord syndrome

Back 58

Posterior cord: lesion in posterior column means loss of vibration and proprioception

Anterior cord: lesion in anterior column means loss of pain, temp and motor

Front 59

Describe transverse cord lesion (severed cord) and hemicord lesion (partial severed cord)

Back 59

Transverse cord: loss of everything below level of lesion

Hemicord: pain and temp loss contralateral and vibration, proprioception and motor loss ipsilaterally.

Front 60

Describe Central cord syndrome small and large lesions

Back 60

small: affects arm pain and temp first

Large: affects everything below the lesion.

Front 61

What are the four unconscious pathways

Back 61

dorsal spinocerebellar

ventral spinocerebellar

cuneocerebellar

rostral spinocerebellar

Front 62

Describe the path of the dorsal spinocerebellar

Back 62

First order: dorsal root ganglion

Second order: dorsal nucleus of clark

Crossing: no

Cerebellar peduncle: inferior

Limb: lower limb same side

Front 63

Describe the path of the ventral spinocerebellar tract

Back 63

First order: dorsal root ganglion

Second order: spinal border nucleus

Crossing: crosses then re-crosses

Cerebellar peduncle: superior

Limb: lower limb same side

Front 64

Describe the path of the cuneocerebellar tract

Back 64

First order: dorsal root ganglion

Second order: accessory cuneate nucleus

Crossing: no

Cerebellar peduncle: inferior

Limb: upper limb same side

Front 65

Describe the path of the rostral spinocerebellar tract

Back 65

First order: dorsal root ganglion

Second order: spinal border nucleus

Crossing: no

Cerebellar peduncle: superior

Limb: upper limb same side