spinal cord and dysfunction

Question 1

numbers of spinal nerves and segments and where nerves leave

Answer 1

31 PAIRS (also 31 spinal segments): 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal, with nerves leaving column through intervertebral foramina

Question 2

enlargements

Answer 2

to innervate limbs, there are enlargements in cervical (C3-T1) and lumbar (L1-S3) region, for innervation of upper and lower limbs respectively

Question 3

relationship between spinal and vertebral levels

Answer 3

C1-7 are above the corresponding nerves, but because there are 7 cervical nerves yet 8 cervical vertebrae, from C8, the rest of the nerves are below their corresponding vertebrae also spinal cord is much shorter than vertebral column, hence at top, there is not much discrepancy between where the nerve emerges from spinal cord, and where it emerges from vertebral column, but this discrepancy becomes larger as you go down, so nerves at the bottom become more angled eg T8 can either be vertebral bone or spinal segment

Question 4

meningeal coverings

Answer 4

dura, arachnoid and pia mater in brain, no space between skull and dura, but there is in spine, so anaesthetics can be injected into epidural space however, there is subarachnoid space in both between pia and arachnoid, where CSF is present, and can be removed in lumbar puncture in spinal cord to test for infection

Question 5

epidural anaesthetic DIAGRAM

Answer 5

because spinal cord ends at L2, needle can be injected without damaging spinal cord, especially if general anaesthetic can’t be used no pia mater as it ends at L2

Question 6

dermatome

Answer 6

area of skin supplied by a single pair of spinal nerves- these are horizontal lines in the chest

Question 7

myotome

Answer 7

collection of muscle innervated by single pair of spinal nerves

Question 8

cross section of spinal cord and ramus vs root DIAGRAM

Answer 8

anterior and posterior roots go to anterior/motor and posterior/sensory roots, which join to form a spinal nerve spinal nerve then divides into a small posterior ramus (innervates back) and large anterior ramus therefore ramus contains both sensory/motor, root doesn’t

Question 9

autonomic outflow

Answer 9

SNS mainly confined to cord, PNS mainly brain and sacral cord motor neurons of SNS only emerge from thoracolumbar region

Question 10

factors affecting spinal lesions

Answer 10

loss of neural tissue- metastases and degenerative diseases cause the worst vertical level- the higher the lesion, the greater the disability transverse plane- the back of spinal cord is mainly sensory, front motor, leading to different symptoms. right side and left side innervate different sides of body

Question 11

causes of spinal injury

Answer 11

due to road accidents, sports or falls

Question 12

injury to lateral corticospinal tract

Answer 12

stage 1- loss of reflex activity below lesion, leading to flaccid paralysis due to spinal shock stage 2- return of reflexes but they motor neurons are super excitable (hyperflexia), leading to rigid paralysis

Question 13

interlateromedial cell column

Answer 13

white matter that allows sympathetic innervation from T1-L1

Question 14

difference between cervical and lumbar spinal cord cross section

Answer 14

cervical has more white matter (as still has to supply most of body compared to lumbar, which supplies legs)

cervical is thus larger

cervical has cuneate fasciculus- part of grey matter that transmits information to upper limbs

Question 15

lesions above medulla

Answer 15

contralateral sensory AND motor deficit

Question 16

lesion below medulla- hemisection

Answer 16

aka browan sequard syndrome= IPSILATERAL loss of touch/proprioception and CONTRALATERAL loss of pain/temp

also IPSILATERAL paralysis

Question 17

spinal vs epidural

Answer 17

into CSF vs into epidural space

no catheter vs catheter

epidural used in child delivery