Spinal cord function and dysfunction Flashcards Preview

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Flashcards in Spinal cord function and dysfunction Deck (20)
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1
Q

Where do the sensory nerves have their cell bodies?

A

Dorsal root ganglion.

2
Q

Where do the motor nerves have their cell bodies?

A

Within the grey matter of the spinal cord.

3
Q

What are the major tracts of the spinal cord?

A
Fasciculus gracilis
Fasciculus cuneatus
Anterior white commissure
Anterior corticospinal tract 
Spinocerebellar tract
Lateral corticospinal tract
Spinothalamic tract
4
Q

What is the role of the fasciculus gracilis?

A

Sensory (fine touch, vibration, proprioception) from ipsilateral lower limb.

5
Q

What is the role of the fasciculus cuneatus?

A

Sensory (fine touch, vibration, proprioception) from ipsilateral upper limb.

6
Q

What is the role of the anterior white commissure?

A

Pain and temperature fibres cross.

Anterior corticospinal tract fibres cross.

7
Q

What is the role of the spinothalamic tract?

A

Pain and temperature from contralateral side of body.

8
Q

What is the role of the lateral corticospinal tract?

A

Motor to ipsilateral anterior horn (mostly limb musculature).

9
Q

What is the role of the spinocerebellar tract?

A

Proprioception from limbs to cerebellum.

10
Q

What is the role of the anterior corticospinal tract?

A

Motor to ipsi- and contralateral anterior horn (mostly axial musculature).

11
Q

What is the corticospinal tract and its path?

A

Begins in cortex.
Decussates in medulla- opposite side in lateral tract, same side in anterior tract.
Main descending pathway for voluntary movement.

12
Q

What is the dorsal column pathway?

A

Discriminative touch, vibration and proprioception.
First order neuron enters spinal cord, travels up on ipsilateral side and synapses with second order neuron, decussates to contralateral side, travels through medial lemniscus then synapses with third order neuron in the thalamus (ventral posterolateral nucleus).

13
Q

What is the spinothalamic tract?

A

Pain and temperature.
First order neuron in dorsal root ganglion enters spinal cord, travels up and synapses with second order neuron which decussates to contralateral side in the anterolateral system of the spinothalamic tract, then synapses with third order neuron in the thalamus (ventral posterolateral nucleus).

14
Q

What is the knee reflex pathway?

A

Patellar tendon hit with hammer.
Fibre from muscle spindle senses stretching of muscle.
Fibre synapses directly with alpha-motor neuron in anterior horn.
Fibre synapses with inhibitory interneuron.
Alpha-motor neurons to the extensor muscle are excited.
Inhibitory interneuron inhibits the alpha-motor neuron of the antagonist muscle.
Alpha-motor neuron of antagonist muscle is inhibited.
Quadriceps muscles contract and leg kicks.

15
Q

What factors affect the severity of a spinal lesion?

A

Loss of neural tissue
Vertical level
Transverse plane

16
Q

How may loss of neural tissue vary the severity of a spinal lesion?

A

Usually small if due to trauma.

Can be more extensive, e.g. metastases, degenerative disease.

17
Q

How does the vertical level of a spinal lesion affect its severity?

A

Higher the lesion, greater the disability.

18
Q

What are the most common causes of spinal cord injury?

A

Broken neck or back.

Road traffic accidents, accidents during sports or recreation, falls in older people.

19
Q

How many people become paralysed in the UK every day and year as a result of spinal cord injury?

A

2-3 people per day.

Over 700 each year, adding to the 40,000 living in the UK that are already paralysed.

20
Q

What are the stages of injury to the lateral corticospinal tract?

A

Stage 1: Spinal shock- loss of reflex activity below the lesion, lasting for days or weeks = flaccid paralysis.
Stage 2: Return of reflexes- hyperreflexia and/or spasticity = rigid paralysis.