Spinal Nerves

Question 1

What happens in a lumbar puncture?

Answer 1

Introduction of needle into subarachnoid space

Question 2

Where is needle inserted in lumbar puncture?

Answer 2

Below level of spinal cord termination - lower risk of spinal cord damage

Question 3

Uses of lumbar puncture:

Answer 3

CSF for analysis

Administration of drugs - intrathecal

Therapeutic

Specific investigations

Question 4

Give examples of how lumbar puncture can be used in administration of drugs:

Answer 4

Local anaesthetic

Chemotherapy

Analgesics e.g. painkillers

Question 5

Give examples of how lumbar puncture can be used in specific investigations:

Answer 5

Myelography and cisternography (in brain)

Question 6

Contraindictions to lumbar puncture:

Answer 6

Raised intracranial pressure

Abnormal clotting or anticoagulant therapy

Local infection leading to risk of epidural abscess

Question 7

Indications on body of where to have lumbar puncture:

Answer 7

Feel for iliac crest

Use L4 vertebral spinous process as a guide

Question 8

Optimal anatomical location for lumbar puncture:

Answer 8

L2/3

L3/4

L4/5

Question 9

Layers lumbar puncture goes through:

Answer 9

Skin

Subcutaneous tissue

Supraspinous ligament

Interspinous ligament

Ligamentum flavum

Epidural space

Dura mater

Arachnoid mater

Subarachnoid space

Question 10

Mnemonic for layers lumbar puncture goes through:

Answer 10

SSS I LED AS

Question 11

What is CSF like?

Answer 11

Clear and colourless fluid

Question 12

What produces CSF?

Answer 12

Choroid plexus

Ependymal cells in ependymal lining of ventricles of the brain

Question 13

What also contributes to CSF?

Answer 13

Extracellular fluid of brain parenchyma

Question 14

What results can we obtain from collecting CSF?

Answer 14

Appearance

Opening pressure

Glucose

Protein

Gram stain and culture

Question 15

Where are cell bodies of motor neurons found?

Answer 15

Ventral side spinal cord

Question 16

What carries impulses from CNS to skeletal muscles?

Answer 16

Somatic motor efferents

Question 17

Route of somatic motor efferents to skeletal muscles:

Answer 17

Leave ventral cord

Pass into corresponding dermatomyotome

Question 18

How many somites contribute to an individual muscle?

Answer 18

More than one adjacent somite

Question 19

What does deltoid develop from?

Answer 19

Somites of C5 and C6 cord segments

Question 20

What is deltoid supplied by?

Answer 20

Nerves arising from segments C5 and C6

Question 21

When do somites develop?

Answer 21

Day 20-21

Question 22

What’s a myotome?

Answer 22

Group of muscles innervated by the same peripheral nerve

Question 23

What can myotome be formed from?

Answer 23

More than one spinal cord segment

Question 24

Clinical examination of myotome:

Answer 24

Examination of upper + lower limb

Measurement of muscle ‘power’

Isolation of action being tested

Question 25

Where do sensory neuron cell bodies lie?

Answer 25

In dorsal root ganglia, formed from neural crest cells

Question 26

What carries sensation from periphery to CNS?

Answer 26

Somatic sensory afferents E.g. temperature, pain, touch, proprioception

Question 27

What does each somite give rise to?

Answer 27

A dermatome

Question 28

What does the dermatome do?

Answer 28

Sends somatic sensory fibres to the segment of spinal cord adjacent to the corresponding somite

Question 29

What’s a dermatome?

Answer 29

Area of skin innervated by a single spinal segment

Question 30

What’s the spinal cord divided into?

Answer 30

Segments (related to each somite)

Question 31

What does each spinal cord segment have?

Answer 31

A pair of spinal nerves

Question 32

Number of segments in cervical:

Answer 32

8

Question 33

Number of segments in thoracic:

Answer 33

12

Question 34

Number of segments in lumbar:

Answer 34

5

Question 35

Number of segments in sacral:

Answer 35

5

Question 36

Number of segments in coccygeal:

Answer 36

1

Question 37

What’s each segment of spinal cord associated with?

Answer 37

Each somite that formed the dermatomyotome

Question 38

Constituents of spinal nerve: Motor

Answer 38

Motor neurons innervate the associated myotome

Question 39

Constituents of spinal nerve: Sensory

Answer 39

Sensory neurons innervate the corresponding dermis

Question 40

Constituents of spinal nerve: Sympathetic

Answer 40

Sympathetic neurons to body wall structures (sweat glands) are only in T1-L2

Question 41

What is sympathetic outflow found?

Answer 41

Thoracolumbar

Question 42

Where is cell body of sympathetic neuron found?

Answer 42

Lateral horn (T1-L2)

Question 43

Where is cell body of motor neuron found?

Answer 43

Anterior/ventral horn

Question 44

Where does sensory neuron leave?

Answer 44

Dorsal/posterior horn

Question 45

Where is sensory neuron cell body found?

Answer 45

Dorsal root ganglion

Question 46

Where do neurons pass through after leaving grey matter?

Answer 46

Intravertebral foramen

Question 47

Which root does sensory neuron travel through?

Answer 47

Dorsal root

Question 48

Which root does motor neuron travel through?

Answer 48

Ventral root

Question 49

Which root does sympathetic neuron travel through?

Answer 49

Ventral root

Question 50

What does dorsal ramus supply?

Answer 50

Erector spinae muscles

Question 51

What does ventral ramus supply?

Answer 51

Body wall and limb plexuses

Question 52

What neurons are in posterior/dorsal ramus?

Answer 52

Sensory and motor

Question 53

What neurons are in anterior/ventral ramus?

Answer 53

Sensory and Motor

Question 54

Where are rami comunicantes found?

Answer 54

Near sympathetic ganglion

Question 55

Where is grey ramis cominicans found?

Answer 55

All levels

Question 56

Where is white ramus communicans found?

Answer 56

T1-L2

Question 57

Role of posterior ramus:

Answer 57

Motor to intrinsic back muscles Sensation to skin over back

Question 58

Role of anterior ramus:

Answer 58

Motor innervation to chest wall muscles Sensation to lateral and anterior chest wall