Gross Neuro Anatomy Flashcards

1
Q

How many pairs of spinal nerves are there?

A

31 pairs

  • 8 cervical
  • 12 Thoracic
  • 5 lumbar
  • 5 sacral
  • 1 cocygeal
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2
Q

Where are spinal nerves found?

A

The intervertebral foramina

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3
Q

What is a dermatome?

A

An area of skin supplied with sensory innervation from a single spinal nerve

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4
Q

What is a Myotome?

A

The skeletal muscles supplied with motor innervation from a single spinal nerve

Can be deep to the dermatome of the same spinal nerve but not always

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5
Q

Which of the following dermatomes is most likely affected by shingles in this image?

  1. T3
  2. T6
  3. T9
  4. T12
A

T6

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6
Q

What is a nerve plexus and give some examples

A

The intermingled anterior rami from a number of adjacent spinal nerves

  • Cervical Plexus- C1-C4, posterior scalp, neck and diaphragm
  • Brachial Plexus- C5-T1, upper limb
  • Lumbar Plexus- L1-L4, lower limb
  • Sacral Plexus- L5-S4, lower limb, gluteal region and perineum
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7
Q

What is the name given the the collection of nerve cell bodies in both the CNS and the PNS?

A

CNS= nucleus

PNS= ganglion

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8
Q

What is responsible for myelin production in both the CNS and PNS?

A

CNS= oligodendroctes

PNS= Schwann cells

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9
Q

What type of neuron is this and what modality does it carry?

A

Multipolar

Motor (efferent)- impulse moves towards the body wall, body cavity or organ

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10
Q

What type of neuron is shown and what modality is it?

A

Unipolar

Sensory (afferent)- the impulse moves towards the brain

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11
Q

Define a nerve?

A

A collection of axons surrounded by connective tissue and blood vessels

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12
Q

What type of innervation has a Thoracolumber outflow?

A

Sympathetic

T1-L2 have lateral horns

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13
Q

What outflow is the parasympathetic described as having?

A

Craniosacral outflow

CNs III, VII, IX, X

Sacral nerves 2,3,4

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14
Q

What are the groups of intrinsic back muscles?

A

Erector Spinae (superficial)

Transversospinalis (deep)

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15
Q

What muscles are shown here and what is there common attachment?

A

Erector Spinae muscles- common tendon attaches to sacrum and iliac crest

  • Iliocostalis (rib between angles and tubercles)
  • Longissimus (transverse process of vertebrae)
  • Spinallis (spinous process of vertebrae)
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16
Q

What group of muscles is shown here?

A

Transversospinalis

Located between the transverse and spinous processes

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17
Q

What movements does the atlanto-occipital joints allow?

A

Flexion and Extension of the neck- main movement

A little lateral flexion and rotation

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18
Q

What is the main movement of the Atlanto-axial joint?

A

Rotation - shaking head no

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19
Q

Within the spinal colomn, at which vertebral level does the subarachnoid space end?

A

S2

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20
Q

When administering a spinal anesthetic/epidural, what is the safest vertebral level to insert the needle?

A

L3/4

Spinal cord ends at level L2 and subarachnoid space ends at level S2. Want to get somewhere in the middle as the needle tip can brush past the cauda equina and avoid damaging the nerves.

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21
Q

Describe the anatomy of caudal anesthesia

A

Local anesthetic is injected into the sacral hiatus into the epidural space. This anestetises the sacral spinal nerve roots of the cauda equina.

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22
Q

What is a laminectomy?

A

The removal of one or more spinous processes and the adjacent laminae. Gives access to/relives pressure on the spinal cord or nerve roots.

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23
Q

Describe muscle spasticity

A

The muscle has an intact and functioning motor nerve

The descending controls from the brain are not working

On examination the muscle would have increased tone

24
Q

What is the nerve point of the neck and where is it located?

A

It is the point where all the cutaneous branches of the cervical plexus converge to become superficial

Located just above the mid-point of the superior border of the SCM

25
Q

What is a reflex?

A

An involuntary response to a stimulus- tests motor and sensory function together

A reflex only works if all parts of the route is intact and there is no damage

26
Q

Describe muscle paralysis

A

Muscle without a functioning motor nerve supply is paralysed

A paralysed muscle cannot contract

On examination the muscle will have reduced tone

27
Q

What are the 3 divisions of the Trigeminal nerve?

A
  • Opthalmic CNV1- sensory
  • Maxillary CNV2- sensory
  • Mandibular CNV3- sensory and motor
28
Q

What base of skull foraminae do the divisions of the trigeminal nerve pass through?

A

CNV1= superior orbita fissure

CNV2= Foramen rotundum

CNV3= Foramen ovale

29
Q

What supplies motor innervation to the muscles of mastication?

A

The mandibular division of the trigeminal nerve- CNV3

(CNV3 also supplies the tensor veli palatini and the tensor tympani)

30
Q

Describe the chorda tympani nerve

A

It is a branch of CNVII (facial nerve)

It connects with the lingual nerve branch of CNV3

  • Taste axons - anterior 2/3 of the tongue
  • Parasympathetic axons- secretomotor innervation to submandibular and sublingual salivary glands
31
Q

What are the branches of the facial nerve?

A

To Zanzibar By Motor Car

  • Temporal
  • Zygomatic
  • Buccal
  • Mandibular
  • Cervical
32
Q

What nerve supplies the posterior 1/3 of the tongue?

A

Gossopharyngeal nerve CNIX

Both sensory and special sensory

33
Q

How are the sensory aspects of the cranial nerve tested?

A
  1. Ask patient to close their eyes
  2. Gently brush the skin in each dermatome with a cotton bud
  3. Ask patient to tell you when their skin is being touched
  4. Compare the 2 sides
34
Q

How are the motor aspects of the trigeminal nerve tested?

A
  1. Palpate the strength of the contraction of the masseter and temporalis by asking the patient to clench their teeth
  2. Ask the patient to open their jaw against resistence
35
Q

What would you ask a patient to do to assess the motor function of CNVII (facial)?

A
  • Frown
  • Close eyes tightly
  • Smile
  • Puff out chees
36
Q

How is the vagus nerve tested?

A
  • Ask patient to say ‘ah’- uvula should lift straight up in the midline
  • Ask patient to swallow a small amount of water- watch larynx movement, splutter may suggest abnormal swallow
  • Listen to speech- voice hoarseness may suggest abnormal function of the muscles of the larynx
  • Ask patient to cough
37
Q

How is the spinal accessory nerve examined?

A

Supplies motor to SCM and Trapezius

Ask patient to shrug shoulders

Ask patient to turn head to look up toward the opposite side

38
Q

How is the hypoglossal nerve tested?

A

Ask patient to stick tongue out straight

If both CNXIIs are functioning normally then the tip of the tongue should remain in the midline

If there is a unilareral CNXII pathology then the tongue will point towards the side of the injured nerve

39
Q

What are the layers of the scalp?

A
  • Skin
  • Connective tissue
  • Aponeurosis
  • Loose connective tissue
  • Pericranium
40
Q

What is highlighted here?

A

The Pterion

The thinnest part of the skull where the bones meet

Frontal, Parietal, Temporal and Sphenoid meet forming an H shape

41
Q

What artery runs deep to the pterion?

A

Middle meningeal artery

42
Q

What is a SOL?

A

Space Occupying Lession

Abnormal tissue taking up space in the skull

This can lead to increased ICP which can result in herniation

43
Q

What cranial nerve supplies the Dura Mater?

A

CNV

44
Q

What is the diaphragm sellae?

A

A tough sheet of dura mater that forms a rough over the pituitary fossa

45
Q

What is the Tentorium cerebelli?

A

A sheet of dura mater that tents over the cerebellum

Attaches to the ridges of the petrous temporal bones

Has a central gap which allows the brainstem to pass through

46
Q

What is the Falx Cerebri?

A

A midline structure made of dura mater that separates the right and left hemispheres. Attaches to the deep aspect of the skull

  • crista galli of the ethimoid bone- anteriorly
  • internal aspect of the saggital suture
  • internal occupital protuberence- posteriorly
47
Q

What are the dural venous sinuses?

A

Group of sinuses (blood channels) that drain venous blood circulating from the cranial cavity

48
Q

What does this image show?

A

The danger triangle of the face

49
Q

Where is this found and what is it?

A

The circle of willis- located inferiorly to the midbrain, closley related to the pituitary stalk and the optic chiasm within the subarachnoid space

50
Q

What is a extradural haemorrhage?

A

Bleeding between the bone and the dura

Can be caused by trauma to the pterion resulting in a ruptured middle meningeal artery

51
Q

What is a subdural haemorrhage?

A

Bleed that causes separation of dura from the arachnoid

Results from torn cerebral veins which is seen in falls in the elderly

52
Q

What is a subarachnoid haemorrhage?

A

A bleed into the CSF of the subarachnoid space

Can be caused by a ruptured circle of willis (berry) aneyrysm or a congenital aneyrysm

53
Q

What are the 2 main classes of brain herniation?

A

Supratentoral- refers to herniation of structures above the tentoral notch

Infratentoral- structures below it

54
Q

What types of infratentoral herniation are seen?

A
  • Upward
  • Downward or tonsillar herniation
    • The cerebellar tonsils herniate into the foramen magnum
55
Q

What are some types of supratentoral herniation?

A
  • Cingulate (subfalcine)
  • Central
  • Uncal or transtentorial- the uncus (medial part) of the temporal lobe herniates inferior to the tentorium cerebelli
  • Transcalvarial
56
Q

What could lead to a blown pupil?

A

Compression of the occulomotor nerve by an uncal herniation leads to an ipsilateral fixed dilated pupil (blown pupil)