Spinal cord and dysfunction

Question 1

What are the names of the ascending tracts?

Answer 1

Dorsal columns; fasciculus gracile and fasciculus cuneate
Dorsal and ventral spinocerebellar tracts
Lateral and ventral spinothalamic tracts

Question 2

What are the names of the descending tracts?

Answer 2

Tectospinal
Ventral corticospinal 
Lateral corticospinal
Medial reticulospinal
Lateral reticulospinal
Vestibulospinal
Rubrospinal

Question 3

What are the two enlargements of the spinal cord and where are they located?

Answer 3

Cervical enlargement; C3-T2, attachment of the brachial plexus
Lumbosacral enlargement; T9-12 and L2-S3 attachment of the lumbosacral plexus which innervates the lower limbs

Question 4

What is the impact of a transverse cervical lesion (above C4)?

Answer 4

Innervation for registration and the heart is lost

Question 5

What is the impact of a high spinal lesion (C1/C2)?

Answer 5

Cannot breathe unassisted (phrenic nerve controls the diaphragm), sexual and urinary dysfunction

Question 6

What do the sacral nerves innervate?

Answer 6

Perineal (genital) and urinary function

Question 7

What is different about the dura mater in the spinal cord vs cranium?

Answer 7

There is o extradural space in the cranium

Question 8

What is the dura mater of the spinal cord continuous with?

Answer 8

The inner meningeal layer of the cranium

Question 9

What is the filum terminale?

Answer 9

It is a continuation of the pia mater from the apex of conus medullar is to the posterior surface of the coccyx (forms the coccygeal ligament)

Question 10

What are the spinal nerves covered by?

Answer 10

Dura mater which later merge with the epineurium

Question 11

At what level does the arachnoid mater cease and what is the purpose of the subarachnoid space?

Answer 11

S2
Subarachnoid space contains CSF
The arachnoid trabeculae connect the arachnoid and pia mater and suspend blood vessels (spinal arteries)

Question 12

What is the basic blood supply to the spinal cord?

Answer 12

One anterior spinal artery
Two posterior spinal arteries
Radicular arteries

Question 13

What is a possible route of entry into the spinal cord for metastasis?

Answer 13

Internal and external vertebral venous plexuses

Question 14

What are the denticulate ligaments?

Answer 14

Extensions of pia mater
Laterally attaching to the arachnoid and dura mater
Medially is attaches to the spinal cord

Question 15

What is the subarachnoid space called in the spinal cord?

Answer 15

Lumbar cistern

Contains the Lumbar and sacral spinal roots (cause equina)

Question 16

Why should you not carry out a lumbar puncture with a raised intracranial pressure?

Answer 16

It will create a pressure gradient; the high pressure will force the brain through the foramen magnum causing a tonsillar herniation -> cardiorespiratory arrest

Question 17

What are the three factors affecting the degree of deficit from a spinal cord lesion?

Answer 17

Loss of neural tissue
Level of spinal cord affected
Transverse plane (how many tracts are affected)

Question 18

What happens when there is a hemisection at the mid-thoracic level?

Answer 18

Brown-Sequard syndrome
Loss of motor function (hemiparaplegia)
Loss of two point discrimination
Loss of motor function on the ipsilateral side
Loss of pain and temperature sensation on the contralateral side

Question 19

Describe the corticospinal tract and its functions

Answer 19

Consists of the lateral and ventral corticospinal tracts
Contain Betz/Pyramidal cells (largest)
Involved in voluntary motor function
Connects to spinal motor neurones
Cross over to contralateral side at the medulla oblongata
Descend in the medullary pyramids and corticobulbar tracts

Question 20

Describe the corticobulbar tract and its functions

Answer 20

Involved in voluntary movement of the head and neck

Involves upper motor neurones of the cranial nerves and terminate on the brainstem motor nuclei

Question 21

Describe the spinothalamic tract and its functions

Answer 21

Sensory neurones will synapse with a neurone in the dorsal horn
The fibres will decussate at the spinal cord level it enters and then ascends
Transmits information about pain and temperature to the thalamus

Question 22

Describe the dorsal columns (medial leminscus) and its functions

Answer 22

Sensory neurones carry information up and will decussate at the medulla oblongata to the cuneate or gracile fasciculus tracts
They then cross at the secondary decussation forming a new tract called the medial leminscus
They synapse at the thalamus, giving information on proprioception and fine touch

Question 23

Describe the reticulospinal tract and its functions

Answer 23

Extrapyramidal motor tract
Descends from the reticular formation into lateral and medial tracts
Acts on motor neurones supplying the trunk and proximal limbs
Facilitates and inhibits voluntary movement and muscle tone
Involved in modulation of nociception

Question 24

Describe the vestibulospinal tract and its functions

Answer 24

Extrapyramidal tract in the medial pathway of the spinal cord
Relays information from the vestibulococchlear nerve about changes in the orientation of the head
Helps alter muscle tone/extend/change position of the head and limbs to support posture and balance of the body

Question 25

What are the effects of a lateral corticospinal tract lesion?

Answer 25

1. Spinal shock; loss of all reflex activity below lesion, flaccid paralysis
2. Hyperreflexia and Spasicity, rigid paralysis