M6 SPINAL CORD Flashcards

1
Q

Connects the brain with most of the body

A

Spinal cord

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2
Q

Occupies the upper 2/3 of the adult spinal canal within the vertebral column

A

Spinal cord

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3
Q

Normally 42 to 45 cm long

A

Spinal cord

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4
Q

Is the conical distal (inferior) end of the spinal cord

A

Conus medullaris

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5
Q

In adults, the conus ends at what level of the vertebral column?

A

L1 OR L2

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6
Q

What nuerons do the lateral enlargements at the cervical and lumbosacral levels accomodate?

A

Upper and lower limb innervation

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7
Q

It is inferior to the end of the spinal cord.

A

Filum terminale

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8
Q

It is a bundle of connective tissue and glia that connects the end of the cord to the coccyx.

A

Filum terminale

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9
Q

Filum terminale is a bundle of ______________ and ____ that connects the end of the cord to coccyx?

A

Connective tissue and glia

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10
Q

Long roots are required for axons from the termination of the cord to exit the lumbosacral vertebral column.

A

Cauda equina

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11
Q

Is lined with ependymal cells and filled with csf.

A

Central canal

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12
Q

Central canal is lined with what? And filled with what?

A

Ependymal cells and CSF

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13
Q

Opens upward into the inferior portion of the fourth ventricle

A

Central Canal

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14
Q

Spinal Cord Segments (adults)

A

C8, T1, T12, L5, S

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15
Q

Vertebral Bodies of C8

A

C6-7

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16
Q

Vertebral Bodies of T1

A

C7-T1

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17
Q

Vertebral Bodies of T12

A

T10-T11

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18
Q

Vertebral Bodies of L5

A

T12-L1

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19
Q

Vertebral Bodies of S

A

L1-2

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20
Q

Bony spinous processes (adults)

A

C6, T3, T8, T10, and T12,L1

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21
Q

Anatomy of spinal cord, superior to inferior.

A

Conus medullaris, cauda equina, and filum terminale

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22
Q

Cross section of the spinal cord

A

Deep median fissure and shallow posterior median sulcus

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23
Q

Divides the cord into symmetric right and left halves joined in the central midportion

A

Deep median fissure

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24
Q

Contains a fold of pia and blood vessels

A

Anterior median fissure

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25
Q

Floor of anterior median fissure

A

Anterior white commissure

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26
Q

Attached to the spinal cord along a shallow vertical groove

A

Dorsal nerve roots

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27
Q

Lies at a short distance anterior to the posterior median sulcus

A

Posterolsteral sulcus

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28
Q

Where do ventral nerve roots exit?

A

Anterolateral sulcus

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29
Q

True or false:
Each segment of the spinal cord gives rise to four roots.

A

True

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30
Q

How many pairs of spinal nerves has a ventral root and a dorsal root?

A

31 pairs

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31
Q

Each root is made up of how many rootlets?

A

1 to 8 rootlets

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32
Q

Axons sending information to the periphery leave the anterolateral cord in small groups

A

Rootlets

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33
Q

Dorsal root of a typical spinal nerve, close to the junction with the ventral root

A

Dorsal root ganglion

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34
Q

A swelling that contains nerve cell bodies that give rise to sensory axons

A

Dorsal root ganglion

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35
Q

Portion of a spinal nerve outside the vertebral column

A

Peripheral nerve

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36
Q

Surrounds and protects the spinal cord

A

Vertebral column

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37
Q

Vertebraes

A

7 cervical
12 thoracic
5 lumbar
1 sacrum
1 coccyx

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38
Q

Exit of nerve roots from the vertebral column

A

Intervertebral foramina

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39
Q

Form from the ventral rootlets from a single segment coalesce

A

Ventral roots

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40
Q

Contains sensory axons that bring information into the spinal cord and enter the posterolateral spinal cord via rootlets

A

Dorsal root

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41
Q

Has a dorsal root ganglion located outside the spinal cord

A

Dorsal root

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42
Q

Contains the cell bodies of sensory neurons

A

Dorsal root ganglion

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43
Q

Sensory axons enter the spinal cord, the large-diameter fibers, transmitting proprioceptive and touch information, are located medially: small-diameter fibers, transmitting pain and temparature information are located laterally

A

Dorsal root ganglion

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44
Q

Sensory axons that transmit proprioceptive and touch information that are located medially.

A

Large diameter fibers

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45
Q

Sensory axons that transmit pain and temperature information that are located laterally.

A

Small diamete fibers

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46
Q

What roots join briefly to form a spinal nerve?

A

Dorsal and ventral

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47
Q

Smaller gamma motor neuron axons supply?

A

Intrafusal muscle of the muscle spindles

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48
Q

Preganglionic autonomic fibers:

A

Thoracic, upper lumbar, and midsacral levels

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49
Q

Largely sensory

A

Dorsal root

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50
Q

Contains afferent fibers from the nerve cells in its ganglion

A

Dorsal nerve root

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51
Q

*contains fibers from cutaneous and deep structures

A

Dorsal root

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52
Q

Largest fibers come from muscle spindles and participate in spinal cord reflexes

A

Dorsal root

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53
Q

Impulses from mechanoreceptors in skin and joints

A

Dorsal root

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54
Q

Nerve roots are small and carry

A

Dorsal root

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55
Q

Branches of typical spinal nerves

A

Posterior primary division, anterior primary division, and Rami communicantes

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56
Q

Medial branch, largely sensory and lateral brach, mainly motor

A

Posterior primary division

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57
Q

Larger than the posterior primary division

A

Anterior primary division

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58
Q

Forms the cervical, brachial, and lumbosacral plexus

A

Anterior primary division

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59
Q

Thoracic region, it remains segmental as intercostal nerves

A

Anterior primary division

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60
Q

Join the spinal nerves to the sympathetic trunk

A

Rami communicantes

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61
Q

Only the thoracic and upper lumber nerves with white ramus communicans, but the gray ramus is present in all spinal nerves

A

Rami communicantes

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62
Q

Made up of two symmetric portions joined across the midline

A

Gray matter: Columns

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63
Q

Cross section of the spinal cord shows an H shaped internal mass of gray matter surrounded by white matter

A

Columns

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64
Q

Extends the entire length of the spinal cord and is considered to consist of columns

A

Gray matter

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65
Q

Column in front of the central canal

A

Ventral gray column

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66
Q

It contains the cells of origin of the fibers of the ventral roots, incl. Alpha and gamma motor neurons

A

Ventral gray column

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67
Q

Lies between the dorsal and ventral gray columns

A

Intermediolateral gray column

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68
Q

Columns is also called?

A

Horn

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69
Q

Prominent lateral triangular projection in the thoracic and upper lumber regions but not in the midsacral joint

A

Intermediolateral gray column

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70
Q

Give rise to sympathetic axons that leave the spinal cord within the ventral roots

A

Lateral horn

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71
Q

Gives rise to preganglionic parasympathetic axons that leave the spinal cord within the sacral ventral roots

A

Sacral parasympathetic neurons

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72
Q

Reaches almost to the posterolateral sulcus

A

Dorsal gray column

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73
Q

A compact bundle of small fibers; part of the brain pathway, lies on the periphery of the spinal cord

A

Dorsolateral fasciculus

74
Q

A cross section of the gray matter of the spinal cord shows a number of laminas

A

Rexed’s laminae

75
Q

Classified into 10 histologic regions of spinal gray matter

A

Rexed’s laminae

76
Q

General principle, superficial laminae tend to be involved in pain signaling while deeper laminae are involved in non painful as well as painful sensation

A

Rexed’s laminae

77
Q

How many laminas do the spinal cord have?

A

10 laminas

78
Q

The thin marginal layer contains neurons

A

Lamina I

79
Q

Respond to noxious stimuli and send axons to the contralateral spinothalamic tract

A

Lamina I

80
Q

Made up of small neurons, some of which respond to noxious stimuli

A

Lamina 2 Substansia Gelatinosa

81
Q

A neuropeptide involved in pathways mediating sensibility to pain, is found in high concentrations in laminas 1 and 2

A

Substance P

82
Q

Main input is from fibers that convey position and light touch sense

A

Laminas 3 and 4 nucleus propius

83
Q

Contains cells that respond to both noxious and visceral afferent stimuli

A

Lamina 5

84
Q

Deepest layer of dorsal horn contains neurons that respond to mechanical signals from joint and skin

A

Lamina 6

85
Q

Represent motor neuron groups in the medial and lateral portions of the ventral gray column

A

Laminas 8 and 9

86
Q

Contains the LMNs that innervate axial musculature

A

Medial motor neuron column

87
Q

Contains the LMNs for the distal muscles of the arm and leg

A

Lateral motor neuron column

88
Q

Represents the small neurons around the central canal or its remnants

A

Lamina 10

89
Q

White columns are called?

A

Funiculi

90
Q

Divided into a medial portion and a lateral portion

A

Cervical and upper thoracic regions

91
Q

Lies between the posterolateral sulcus and the anterolateral sulcus

A

Lateral column

92
Q

Lies between the anterolateral sulcus and the anterior median fissure

A

Ventral column

93
Q

Arising from the cerebral cortex

A

Corticospinal tract

94
Q

A large bundle of myelinated axons that descend through the brain stems via a tract called the medullary pyramid and then largely crosses over downward into the lateral white columns.

A

Corticospinal tract

95
Q

Contains axons of upper motor neurons

A

Corticospinal tract

96
Q

Anterior horn cells, which project directly to muscle and control muscular contraction

A

Lower motor neurons

97
Q

2 major components of the vestibulospinal tract

A

Lateral and medial vestibulospinal tract

98
Q

Fibers arise from the lateral vestibular nucleus in the brainstem and course downward, uncrossed, in the ventral white column

A

Lateral vestibulospinal tract

99
Q

Fibers arise in the medial vestibular nucleus in the brainstem and descend within the cervical spinal cord, with both crossed and uncrossed components, to terminate at cervical levels

A

Medial vestibulospinal tract

100
Q

Provides synaptic inputs to interneurons in rexed’s laminae 7 and 8 which project to both alpha and gamma LMNs.

A

Fibers of both vestibulospinal tracts

101
Q

Facilitates quick movements in reaction to sudden changes in body position and provides control of antigravity muscles

A

Vestibulospinal system

102
Q

Fiber system arises in the contralateral red nucleus in the brain stem and courses in the lateral white column

A

Rubrospinal tract

103
Q

Projects to interneurons in the spinal gray columns and plays a role in motor function

A

Rubrospinal tract

104
Q

Arises in the contralateral red nucleus in the brain stem and courses in the lateral white column

A

Fiber system

105
Q

Arises in the reticular formation of the brain stem and descends in both the ventral and lateral white columns

A

Reticulospinal system

106
Q

Both crossed and uncrossed descending fibers are present

A

Reticulospinal system

107
Q

The fibers terminating on dorsal gray column neurons may modify the transmission of sensation from the body, especially pain.

A

Reticulospinal system

108
Q

Arising from the hypothalamus and brainstem

A

Descending autonomic system

109
Q

Projects to preganglionic sympathetic neurons in the thoracolumbar spinal cord and to preganglionic parasympathetic neurons in sacral segment

A

Descending autonomic system

110
Q

Modulate autonomic functions, such as blood pressure, pulse and respiratory rates and sweating

A

Descending autonomic system

111
Q

Tract arises from the superior colliculus in the roof of the midbrain then courses in the contralateral ventral white column to provide synaptic input to ventral gray interneurons

A

Tectospinal tract

112
Q

Head turning in response to sudden visual or auditory stimuli

A

Tectospinal tract

113
Q

Convey localized sensations of fine touch, vibration, two point discrimination, and proprioception from the skin and joint.

A

Dorsal column tracts

114
Q

Carries input from the lower half of the body, with fibers that arise from the lowest, most medial segments.

A

Fasciculus gracilis

115
Q

Lies between the fasciculus gracilis and the dorsal gray column

A

Fasciculus cuneatus

116
Q

It carries input from the upper half of the body, with fibers from the lower segments more medial than the higher ones

A

Fasciculus cuneatus

117
Q

Small diameter sensory axons convey the sensations of sharp pain, temperature, and crudely localized touch course upward.

A

Spinothalamic tracts

118
Q

Ascending stretches of incoming fibers that synapse with dorsal column neurons, especially in laminas 1, 2, and 5

A

Dorsolateral fasciculus

119
Q

Subsequent fibers cross to the opposite side of the spinal cord and then ascend within the spinothalamic tracts

A

Ventrolateral system

120
Q

Carries information about light touch

A

Anterior spinothalamic tract

121
Q

Pain and temperature sensibility upward

A

Lateral spinothalamic tract

122
Q

ill defined spinoreticular tract courses within the ventrolateral portion of the spinal cord, arising from cord neurons and ending in the reticular formation of the brainstem

A

Spinoreticular pathway

123
Q

Plays an important role in the sensation of pain, especially deep, chronic pain

A

Spinoreticular pathway

124
Q

Two ascending pathways provide input from the spinal cord to the cerebellum

A

Spinocerebellar tracts

125
Q

2 pathways of spinocerebellar tracts

A

Dorsal and ventral spinocerebellar tracts

126
Q

Forms the dorsal spinocerebellar tract

A

Second order neurons from dorsal nucleus of Clarke

127
Q

Forms the cuneocerebellar tract

A

Lateral cuneate nucleus

128
Q

Involved with movement control

A

Ventral spinocerebellar tract

129
Q

Second order neurons, located in rexed’s laminae 5, 6, and 7 in lumbar and sacral segments of the spinal cord, send axons that ascend through the superior cerebellar peduncle to the paleocerebellar cortex

A

Ventral spinocerebellar tract

130
Q

The axons of the second order neurons are largely but not entirely crossed

A

Ventral spinocerebellar tract

131
Q

Involves the afferent neuron and its axon within a peripheral nerve and dorsal root and a motor unit at the same level

A

Segmental spinal reflexes

132
Q

Involve specific patterns of muscle contractions, tha delay between stimulation and effect is caused by the time needed for propagation of the impulse along the nerve fibers concerned and the synaptic delay. 1 ms at each synapse

A

Simple reflex reactions

133
Q

True or false:
A reflex arc must be intact for a particular reflex to be present.

A

True

134
Q

Can provide information that is highly useful in the localization of lesions.

A

Evaluation of spinal reflexes

135
Q

Stretch reflexes are also called?

A

Tendon or deep tendon reflexes

136
Q

Provide a feedback mechanism for maintaining appropriate muscle tone

A

Stretch reflexes

137
Q

Depends on specialized sensory receptors, afferent nerve fibers extending from these receptors via the dorsal roots to the spinal cord, two types of LMNs that project back muscle, and specialized inhibitory interneurons.

A

Stretch reflexes

138
Q

Specialized mechanoreceptors are located within muscles and provide information about the length and rate of changes in the length of the muscle.

A

Muscle spindles

139
Q

Muscle spindles surrounded by a connective tissue capsule

A

Intrafusal muscle fibers

140
Q

Regular contractile units that provide the force underlying muscle contraction

A

Extrafusal muscle fibers

141
Q

2 types of intrafusal fibers

A

Nuclear bag fibers and nuclear chain fibers

142
Q

Run longitudinally within the muscle and are arranged in parallel with the extrafusal muscle fibers

A

Septae

143
Q

2 types of afferent axons

A

Ia and II fibers

144
Q

Arise from primary endings and secondary ending on the intrafusal fibers

A

Afferent axons

145
Q

Carry impulses from the muscle spindle to the spinal cord via dorsal roots

A

Afferent axons

146
Q

Responsible for muscle contraction that is innervated by large anterior horn neurons

A

Extrafusal muscle fibers

147
Q

Propagate via axons in the ventral roots and peripheral nerves to the motor end plate where they have an excitatory effect and produce muscle contraction

A

Fire action potentials

148
Q

Have diameters of 12 to 20 micrometer

A

Axons of alpha motor neurons

149
Q

Interneurons, located in the ventral horn, project to alpha motor neurons and are inhibitory

A

Renshaw cells

150
Q

Receive excitatory synaptic input via collaterals, whish branch from alpha motor neurons

A

Renshaw cells

151
Q

Part of local feedback circuits that prevent overactivity in alpha motor neurons

A

Renshaw cells

152
Q

Present with muscle tendons; stretch receptors are arranged in series with extrafusal muscle fibers and are activated by either stretching or contracting the muscle.

A

Golgi tendon organs

153
Q

Group Ib afferent fibers run from the tendon organs via dorsal roots to the spinal gray matter

A

Golgi tendon organs

154
Q

End on interneurons that inhibit the alpha motor neuron innervating the agonist muscle, thus mediating the inverse stratch reflexes

A

Golgi tendon organs

155
Q

This feedback arrangement prevents the overactivity of alpha motor neurons

A

Golgi tendon organs

156
Q

In LMN, the motor cell concerned with striated skeletal muscle activity consists of a ________ and ______ , which passes to the motor end plates of the muscle by way of the ________ nerves.

A

Cell body and axon, cranial

157
Q

Considered the final common pathway because many neural impulses funnel through them to the muscle.

A

Lower motor neurons

158
Q

Acted on by the corticospinal, rubrospinal, olivospinal, vestibulospinal, reticulospinal, and tectospinal tracts as well as by intersegmental reflex neurons

A

lower motor neurons

159
Q

May be located in the cells of the ventral gray column of the spinal cord or brainstem or in their axons, which constitute the ventral roots of the spinal or cranial nerve.

A

Lesions of the LMNs

160
Q

Damage to the cerebral hemispheres or lateral white column of the spinal cord can produce signs of?

A

Upper motor neuron lesions

161
Q

Commonly seen as a result of strokes which can damage?

A

Upper motor neurons in the cortex

162
Q

Signs when these neurons are damaged:
- Spastic paralysis or paresis
- no muscle atrophy
- hyperactive tendon reflexes
- babinski’s sign

A

Upper motor neuron

163
Q

Signs when these neurons are damaged:
- flaccid paralysis
- muscle atrophy
- fasciculations

A

Lower motor neurons

164
Q

Can affect the decussating fibers of the spinothalamic tract from both sides without affecting other ascending or descending tracts

A

Small central lesion

165
Q

Involves in addition to the pain and temp pathways, portions of adjacent tracts, adjacent gray matter, or both.

A

Large central lesion

166
Q

Affects the dorsal columns, leaving other parts of the spinal cord intact

A

Dorsal column lesion

167
Q

Proprioceptive and vibratory sensations are involved, but othe functions are normal

A

Dorsal column lesion

168
Q

Examples are stab wound and compression of the cord

A

Irregular peripheral lesion

169
Q
  • Involves long pathways and gray matter.
  • functions below the level of the lesion are abolished
A

Irregular peripheral lesion

170
Q

Produces a brown séquard syndrome

A

Complete hemisection

171
Q
  • Such as neurofibroma or schwannoma
  • Involves the first order sensory neurons of a segment an can produce pain as well as sensory loss
  • deep tendon reflexes at the appropriate level may be lose because of damage to Ia fibers
A

Tumor of the dorsal root

172
Q
  • compresses the spinal cord against a vertebra causing dysfunction of ascending and descending fiber systems
A

Tumor of the meninges

173
Q

Can metasize to the epidural space causing spinal cord compression

A

Tumors

174
Q

Can also compress the spinal cord

A

Herniated intervertebral disks

175
Q

May be treatable if diagnosed early

A

Spinal cord compression

176
Q

Presents a classical clinical picture, characterized by loss of pain and temperature sensation at several segmental levels

A

Syringomyelia

177
Q

Retains touch and pressure sense as well as vibration and position sense. Lesion usually involves the central part of the spinal cord and is confined to a limited no. of segments.

A

Syringomyelia

178
Q

There is a capelike pattern of sensory loss

A

Cervical region lesion

179
Q

LMN lesions and atrophy of the denervated muscles

A

Ventral gray matter

180
Q

Form the tertiary neurosyphilis was common in the pre antibiotic era and is characterized by damage to the dorsal roots and dorsal columns

A

Tabes dorsalis

181
Q

Impairment of proprioception and vibratory sensation, together with loss of deep tendon reflexes, which cannot be elicited because th Ia afferent pathway has been damaged

A

Tabes dorsalis