6: Anatomy - Spinal nerves Flashcards Preview

Neurology Week 1 2018/19 > 6: Anatomy - Spinal nerves > Flashcards

Flashcards in 6: Anatomy - Spinal nerves Deck (81)
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1
Q

Where does the spinal cord end?

A

L1/2

@ the conus medullaris

2
Q

What is the difference between a spinal nerve and a named nerve?

A

Spinal nerve: contains axons from ONE spinal cord level

Named nerve: contains axons from MULTIPLE spinal cord levels, it gains them as it goes along

3
Q

Which nerve modalities emerge from the

a) anterior horn
b) posterior horn

of the spinal cord?

A

a) Motor (including somatic motor, sympathetic and parasympathetics [from the sacral spinal nerves only])

b) Sensory

4
Q

What is a spinal ganglion?

A

A group of nerve cell bodies found in the POSTERIOR ROOT of each spinal cord level

The neurons in here are the ‘first-order’ neurons for sensory pathways like the DC/ML and spinothalamic tracts

There’s no such thing as an anterior root ganglia, so they’re called dorsal root ganglia

5
Q

Where do many sensory nerves synapse before entering the spinal cord?

A

Dorsal root ganglia

6
Q

Which nerve modalities do spinal nerves contain?

A

Both sensory and motor

7
Q

What nerve modalities are found in spinal nerves?

A

Somatic motor

Somatic sensory

Visceral afferent

Visceral efferent (sympathetics T1 - L2; parasympathetics S1 - 5)

8
Q

Which arc of neurons synapse in the spinal cord to carry out involuntary movements in response to dangerous stimuli?

A

Reflex arc

9
Q

What is neuralgia?

A

Nerve pain

10
Q

What is the medical term for nerve pain?

A

Neuralgia

11
Q

What is paraesthesia?

A

Tingling sensation

“Pins and needles”

12
Q

What is the medical term for pins and needles?

A

Paraesthesia

13
Q

What is anaesthesia?

A

Numbness

14
Q

What is the medical term for numbness?

A

Anaesthesia

15
Q

What is hyperaesthesia?

A

Increased sensitivity

16
Q

What is hypotonia?

A

Loose, floppy muscles

17
Q

What is the medical term for loose, floppy muscles?

A

Hypotonia

18
Q

What is the medical term for a loss of coordination and balance?

A

Ataxia

19
Q

What is ataxia?

A

Loss of coordination and balance

20
Q

How do you test the

a) motor

b) sensory

parts of a spinal nerve?

A

a) Myotomal testing

b) Dermatomal testing

21
Q

How can you test the sensory AND motor aspects of a spinal nerve at the same time?

A

Reflex testing

22
Q

Which part of the brain is the end point for the main sensory pathways?

A

Post-central gyrus of cerebral cortex

Also known as main somatosensory area / sensory strip

23
Q

How do third-order neurons of the sensory pathways get from the thalamus to the post-central gyrus?

A

Internal capsule

24
Q

When testing somatic sensory neurons, which dermatome must you compare your findings to?

A

Contralateral dermatome

tells you if it’s unilateral or bilateral

25
Q

In terms of C1, what is notable about its sensory component (i.e posterior ramus)?

A

It doesn’t have one

26
Q

Describe the dermatome of C1.

A

Doesn’t have one

27
Q

Which structures does the C2 dermatome cover

a) anteriorly
b) posteriorly?

A

a) Adam’s apple

b) Back of scalp

28
Q

Which structures does the C3 dermatome cover

a) anteriorly
b) posteriorly?

A

a) Jugular notch

b) Back of neck

29
Q

Which spinal nerves supply the sensory fibres for the upper limb?

A

C5 - T2

i.e the brachial plexus (C5 - T1) and T2

30
Q

Which area of the upper limb does the C5 dermatome cover?

A

Regimental badge patch area

i.e proximal, lateral arm

31
Q

Which spinal nerves supply sensory fibres to the

a) index finger
b) little finger
c) thumb?

A

a) Index finger - C7

b) Little finger - C8

c) Thumb - C6

32
Q

Which spinal nerves supply sensory fibres for the

a) pubic symphysis
b) umbilicus
c) male nipple?

A

a) Pubic symphysis - T12

b) Umbilicus - T10

c) Male nipple - T4

33
Q

Which spinal nerves supply the sensory fibres for the groin?

A

L1

Think “hands in pockets” to remember the areas of skin

34
Q

Which area of the lower limb is given sensory fibres by L2 and L3?

A

Anterior thigh

Anterior knee

35
Q

Which malleolus is supplied by

a) S1
b) L4?

A

a) Lateral malleolus (S1 supplies the heel, i.e posterior)

b) Medial malleolus (L4 supplies the medial leg)

36
Q

Which area of the lower limb is given sensory fibres by L5?

A

Dorsum of the foot

37
Q

Which aspects of the foot and ankle are given sensory fibres by S1?

A

Plantar surface of foot

Lateral malleolus

38
Q

Which spinal nerve supplies the sensory fibres for the posterior leg and thigh?

A

S2

39
Q

S3, S4 and S5 form a bullseye shape around which structure?

A

Anus

sorry for the imagery

40
Q

What aspects of the trunk are supplied by the

a) anterior horn
b) posterior horn?

A

a) Intercostal muscles

b) Skin (segmentally)

41
Q

What aspect of skin would you palpate to test the action of sensory nerves in the posterior ramus?

A

Back

42
Q

Which area of skin would you palptate to test the action of sensory nerves coming from anterior ramus?

A

Chest and abdomen

43
Q

Which named nerves supply sensory fibres to

a) upper trunk (anterolateral)
b) lower trunk (i.e below the ribcage)?

A

a) Intercostal nerves

b) Subcostal nerve

44
Q

How many spinal nerves are found in named nerves?

A

More than one e.g musculocutaneous nerve, which contains fibres from C5 and C6

45
Q

How do you figure out the dermatomes supplied by named nerves?

A

Figure out which spinal nerve roots are in the named nerve

e.g Femoral nerve is L2-4

so dermatomes are L2, L3 and L4 - anterior leg, thigh and medial malleolus

46
Q

Which spinal nerves form the cervical plexus?

A

C1 - C4

47
Q

Which area of the head and neck is supplied with sensory fibres by the cervical plexus (C1 - C4)?

A

Anterolateral area

so ear, side of neck etc

48
Q

What is Erb’s point?

Where is it?

A

Convergence of cervical plexus (C1-4)

Midpoint of posterior border of SCM

49
Q

Where is Erb’s point found?

A

Midpoint of posterior border of SCM

50
Q

At which point do the cutaneous nerves of the cervical plexus (C1-C4) enter the skin?

A

Erb’s point

Midpoint of the posterior border of SCM

51
Q

Which nerves supply sensory fibres to the

a) anterolateral head and neck
b) face
c) posterior neck and scalp?

A

a) Cervical plexus (C1-4)

b) Trigeminal nerve (CN V1, V2 and V3)

c) C2-8

52
Q

The supraclavicular nerves supply sensory fibres to the clavicle and shoulder.

Why is pain from the diaphragm referred to the shoulder?

A

Diaphragm receives somatic motor fibres and sends visceral afferent fibres via the PHRENIC NERVE (C3, 4 and 5)

Supraclavicular nerves send sensory fibres to C3, 4 and 5

The visceral afferents and supraclavicular nerves plug into the spinal cord at the same levels, so pain can be referred

53
Q

From an anterior dermatome of skin to the posterior horn, what structures does an action potential travel through?

A

Skin

Nerve plexus

Anterior ramus

Spinal nerve

Posterior root, rootlets

Posterior horn

If the sensation was felt posteriorly the AP would travel through the posterior ramus

54
Q

What are the named nerves of the cervical plexus and their spinal levels?

A

Lesser occipital nerve (C2)

Greater auricular nerve (C2 & 3)

Transverse cervical nerve (C2 & 3)

Supraclavicular nerve (C3 & 4)

Little goats tread softly

55
Q

Why does anginal pain sometimes radiate to the upper arm?

A

Myocardium sends visceral afferents to T1 and T2 spinal nerves

T1 and T2 dermatomes are the medial arm and forearm

56
Q

Where is the motor centre of the brain found?

What is it also known as?

A

Pre-central gyrus of the frontal lobe, anterior to the central sulcus

Primary somatomotor cortex / motor strip

57
Q

Which muscles are supplied with somatic motor fibres by the cervical plexus (C1-4)?

A

Muscles of the neck (postural and strap muscles)

Diaphragm (C3,4,5 keeps the diaphragm alive)

58
Q

Which muscles are supplied by somatic motor fibres by the cervical plexus?

A

Neck muscles - postural and strap

Diaphragm

59
Q

Which spinal nerves contribute to the

a) cervical plexus
b) brachial plexus?

A

a) Cervical plexus - C1-C4

b) Brachial plexus - C5-T1

60
Q

Which muscles are supplied by somatic motor fibres by the brachial plexus?

A

Extrinsic back muscles (levator scapulae, rhomboids major and minor and latissimus dorsi; EXCEPT trapezius, which is CN IX)

Upper limb muscles

61
Q

Which muscles are controlled by

a) anterior rami
b) posterior rami

originating from spinal nerves T2-L3?

A

a) Intercostal muscles

b) Intrinsic back muscles (erector spinae and transversospinalis groups)

62
Q

How do you figure out the myotomes supplied by a named nerve?

A

Figure out the spinal nerve roots of the named nerve and then apply all the myotomes of those spinal nerves

63
Q

Which skeletal muscles are supplied by the lumbosacral plexus?

A

Lower limb muscles

Perineal skeletal muscles

64
Q

Where generally are the deltoid muscles found?

A

Shoulder joint

65
Q

Which spinal nerve gives somatic motor fibres to the deltoid?

A

C5

66
Q

Which action does the deltoid muscle perform at the shoulder?

A

Abduction

67
Q

Which named nerve supplies the deltoid muscle?

What are its nerve roots?

A

Axillary nerve

C5-6

68
Q

Which muscle is most responsible for flexion at the elbow?

Which named nerve supplies it?

A

Biceps brachii

Musculocutaneous nerve (C5-6)

69
Q

Which muscle is most responsible for extension at the elbow?

Which named nerve supplies it?

A

Triceps brachii

Radial nerve (C5-T1)

70
Q

What is a reflex?

A

An INVOLUNTARY response to a dangerous stimulus

71
Q

What is the reflex arc?

A

Pathway that action potentials take to trigger a reflex response

72
Q

Do action potentials travel up and down the ascending and descending tracts to trigger a reflex response?

Why?

A

No

Takes too long

73
Q

In a reflex arc, where do action potentials

a) enter the spinal cord
b) exit the spinal cord?

Which type of neuron carries the action potential on their axons?

A

a) Posterior root (sensory)

b) Anterior root (motor)

Lower motor neurons (or LMNs)

74
Q

In a reflex response, action potentials cross straight from the posterior horn to the anterior horn to enact a quick motor response.

Which neurons

a) carry the action potentials
b) act as “descending controls” to stop unwanted movements?

A

a) Lower motor neurons (LMNs)

b) Upper motor neurons (UMNs)

75
Q

What happens to muscle movements if there’s a lesion in the

a) upper motor neurons
b) lower motor neurons

of a reflex arc?

A

a) Spasticity

b) Flaccidity

76
Q

How can spinal reflexes be tested?

A

Tap muscle tendons with a hammer to elicit a reflex (“jerk”) response

77
Q

What reflex tests C5-6 by flexing the elbow?

A

Biceps jerk

Flexion of elbow by biceps brachii

78
Q

What reflex tests C7 by extending the elbow?

A

Triceps jerk

Extension of the elbow by triceps brachii

79
Q

Which reflex tests C6 by supinating/pronating the forearm?

A

Brachioradialis reflex

80
Q

What is the knee jerk reflex?

Which spinal nerve, named nerve and muscle does it test?

A

Extension of flexed knee in response to tapping on patellar tendon

L3; femoral nerve; quadriceps femoris

81
Q

What is the ankle jerk reflex?

Which spinal nerve, named nerve and muscle does it test?

A

Plantarflexion of dorsiflexed foot in response to tapping on Achilles tendon

S1; superficial fibular nerve; gastrocnemius