Session 1.4a - Self-Study

Question 1

Why is an understanding of the cervical fascial layers and deep neck spaces important clinically?

(Clinical Presentation: Retropharyngeal abscesses)

Answer 1

When thinking about relation to deep neck space infections and their potential route of spread.

Question 2

What might a presenting complaint and population be for those presenting with retropharyngeal abscesses?

(Clinical Presentation: Retropharyngeal abscesses)

Answer 2

Population - children under 5

Presenting complaint - unable to move her neck/neck stiffness

Question 3

https://www.youtube.com/watch?v=VnFDdC9sfYM

Try and tie in her clinical symptoms with what you understand of the anatomy of the cervical fascial layers: for example, why might swallowing and moving the head prove painful for the young girl?

(Clinical Presentation: Retropharyngeal abscesses)

Answer 3

The retropharyngeal space is located directly behind the oesophagus. An infection here would cause this space to distend, hence impinging on the oesophagus, and making swallowing hard (substances pass from the mouth, pharynx to the oesophagus; while shutting the epiglottis).

Normally, the fascia also allows for ease of movement between structures, e.g. when swallowing - due to infection the fascia would be inflamed causing friction as the planes rub over each other, making movement difficult and painful.

Similarly, movement of the neck is difficult because posteriorly, the retropharyngeal space when distended would impinge on the muscles associated with the vertebral column; making it hard to move the neck.

Question 4

https://www.youtube.com/watch?v=VnFDdC9sfYM

What would be another very important differential diagnosis to consider when a patient presents unwell, with apparent neck stiffness?

(Clinical Presentation: Retropharyngeal abscesses)

Answer 4

Meningitis

One of the differential diagnoses can be the Brudzinski sign

https://en.wikipedia.org/wiki/Brudzi%C5%84ski%27s_sign

Question 5

IMAGE 1 - 00:08

What are we looking at?

(Internal Carotid Artery Route)

Answer 5

A model showing the skull, brain, and some of the important arteries that run up through the neck to supply various structures of the face and structures intracranially.

Question 6

IMAGE 2 - 00:30

What can we see in this view?

(Internal Carotid Artery Route)

Answer 6

• Looking at the lateral aspect of the neck
• We see the main artery and its branches
• This essentially supplies the entirety of the structures of the face, the skull and intracranial contents

Question 7

IMAGE 2 - 00:30

• Label the CCA, ICA and ECA.
• Label the vertebra
• Draw on the thyroid cartilage

(Internal Carotid Artery Route)

Answer 7

• The CCA bifurcates into the ICA and ECA
• The ECA gives off branches in the neck, whereas the ICA gives off no branches
• The CCA bifurcates at the level of C4
• The superior edge of the thyroid cartilage is C4 (thyroid cartilage roughly C4-C5)

Question 8

How can you identify the difference between the ECA and ICA? What does the ECA supply?

(Internal Carotid Artery Route)

Answer 8

The ECA gives branches within the neck to supply various structures of the face, bones of the face, scalp and tissues of the scalp.

The ICA runs right up the length of the neck without giving any branches, and instead will pass through a tiny hole in the base of the skull, known as the carotid canal.

Question 9

IMAGE 3 - 01:30

Where does the ICA enter the skull (answer without image and then show)

(Internal Carotid Artery Route)

Answer 9

Through the carotid canal

• 01:30

Question 10

IMAGE 4 - 01:36

Label the image

(Internal Carotid Artery Route)

Answer 10

• Foramen ovale
• Pterygoid plates & fossa
• Carotid canal
• Jugular foramen

Question 11

In relation to the ICA, what do we normally find at the site of bifurcation?

(Internal Carotid Artery Route)

Answer 11

A slight swelling, known as the carotid sinus

Question 12

What does the carotid sinus do?

Answer 12

Important baroreceptors that monitor pressure within the vasculature (blood pressure)

Question 13

Why is the carotid sinus important clinically?

Answer 13

Applying firm pressure over the area of carotid sinus (carotid sinus massage) can stimulate baroreceptors - this increases parasympathetic drive to the heart to terminate, hopefully, any potential supraventricular tachycardias (SVTs).

Question 14

IMAGE 5 - 02:15

Label the image

(Internal Carotid Artery Route)

Answer 14

• Carotid sinus

- Vagus nerve

Question 15

IMAGE 6 - 03:00

This view involves removing the brain. Here we can visualise a number of blood vessels.

Label the front and back of the skull.

What will these blood vessels ultimately give rise to?

Answer 15

Front, back - see image.

Arteries supplying the brain

Question 16

How can you potentially terminate a SVT?

Answer 16

By applying a carotid sinus massage.

Question 17

IMAGE 6 - 03:00

Label the ICA

Answer 17

ICA enters through the carotid canal

Question 18

IMAGE 6 - 03:00

Label the carotid canal

Answer 18

See image

Question 19

IMAGE 6 - 03:00

Label the sphenoid bone/body of sphenoid

Answer 19

See image (central bone)

Question 20

What is the dural venous sinus which sits either side of the sella turcica known as?

Answer 20

Cavernous sinus

Question 21

IMAGE 6 - 03:00

Label the sella turcica

Answer 21

See image (central depression)

Question 22

IMAGE 6 - 03:00

Label the petrous bone

Answer 22

Bone on middle lateral edges

Question 23

Describe the route of the ICA in the skull.

Answer 23

The ICA arises from the carotid canal in the petrous bone, coming through and running towards the body of the sphenoid bone. Here it runs into the cavernous sinus, which is a dural venous sinus which sits either side of the sella turcica. As it emerges through the top of the cavernous sinus, this is when it gives its branches.

Question 24

IMAGE 7

Label the image and caption it with specific description of image.

Answer 24

• ORBIT and EYE
• OPTIC CANAL with ophthalmic artery from ICA
• ophthalmic vein
• posterior clinoid process (sella turcica)
• superior petrosal sinus
• inferior petrosal sinus
• petrous part of temporal bone
• carotid canal
• cavernous sinus
• emissary vein connecting to pterygoid venous plexus
• ICA

Looking laterally towards right hand side of sella turcica on cranial floor

Question 25

The ophthalmic artery is a branch of which artery?

Answer 25

The ICA

Question 26

IMAGE 8 Label the ophthalmic artery

Answer 26

Runs through the optic canal

Question 27

Where does the ophthalmic artery lie in the skull?

Answer 27

Essentially arises just after the CCA (ICA?) has emerged to the top of the cavernous sinus

Question 28

The ophthalmic artery gives a branch that runs through where with the optic nerve?

Answer 28

Optic canal

Question 29

The optic nerve runs through where with what?

Answer 29

The optic canal with a branch of the ophthalmic artery.

Question 30

The opthalmic artery gives branches that will supply what?

Answer 30

Structures of the eye

Question 31

Name the artery that supplies the sight-sensing part of the eye.

Answer 31

Sight-sensing part = retina Central retinal artery

Question 32

Name the branch and its origin artery to the retina.

Answer 32

The central retinal artery, from the ICA.

Question 33

What is the function of the retina?

Answer 33

Senses sight

Question 34

IMAGE 9 Label the central retinal artery, optic nerve, and internal carotid artery. Label any other arteries if known. Give this image a caption.

Answer 34

Medial palpebral artery; short posterior ciliary arteries; anterior ethmoidal artery; central retinal artery; posterior ethmoidal artery; optic nerve; internal carotid artery; supraorbital artery; long posterior ciliary artery; lacrimal artery Looking from above at the right orbit.

Question 35

The ICA gives off other branches which you will learn about in SEM4. However, as well as the ophthalmic artery, when the ICA emerges from the top of the cavernous sinus, which two arteries does it give off?

Answer 35

The anterior cerebral artery and the middle cerebral artery.

Question 36

IMAGE 9 Label the anterior and middle cerebral arteries.

Answer 36

See image

Question 37

What do the branches of hte ICA do in the skull?

Answer 37

They form an arterial circuit known as the circle of Willis

Question 38

IMAGE 10 Identify the circle of Willis.

Answer 38

See image

Question 39

Where does the circle of Willis sit?

Answer 39

Right at the base of the skull

Question 40

IMAGE 10 Label the foramen magnum

Answer 40

At back of skull

Question 41

IMAGE 10 Label the spinal cord

Answer 41

Yellow - cut through

Question 42

What are the arteries running up through the foramen magnum?

Answer 42

Vertebral arteries

Question 43

Where do the vertebral arteries run through?

Answer 43

The transverse foramen of the cervical vertebrae, through the foramen magnum.

Question 44

The two vertebral arteries join to form which artery?

Answer 44

The basilar artery

Question 45

The basilar artery is formed from which arteries?

Answer 45

The two vertebral arteries (from the left and right side)

Question 46

IMAGE 10 Label the basilar artery

Answer 46

Runs along clivus (slope) of occipital bone

Question 47

Where does the basilar artery run?

Answer 47

Along the sloping part (clivus) of the occipital bone

Question 48

Which bone does the basilar artery lay on?

Answer 48

The occipital bone

Question 49

What does clivus mean?

Answer 49

Latin for slope

Question 50

The basilar artery joins which arteries to form what?

Answer 50

Branches of the ICA to form the circle of Willis

Question 51

What supplies blood to the brain tissue itself?

Answer 51

Branches of the circle of Willis

Question 52

Branches of the circle of Willis supply blood to what?

Answer 52

The brain tissue itself

Question 53

The petrous bone is part of which bone?

Answer 53

The temporal bone

Question 54

On a cadaveric specimen, we wouldn't actually see the cavernous sinus. Why is this?

Answer 54

A dural fold would sit around it

Question 55

Describe the ICA and its route intracranially.

Answer 55

It comes up through the common carotid canal in the petrous part of the temporal bone, through the cavernous sinus (covered by a dural fold) and as it emerges gives rise to the ophthalmic artery and other arteries involved in the circle of Willis.

Question 56

What is the normal heart rate? | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 56

Anywhere between 60, and if you're active, a 100.

Question 57

What is a typical heart rate of someone with SVT? | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 57

Can go suddenly to beats such as 170 (or higher)!

Question 58

A racing heart can be a result of many things. Suggest some. | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 58

- Anxiety - Stress - Medications - Heart disease

Question 59

What could happen to an older patient who's had heart disease or a weak heart? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 59

- Collapse (syncope) - Heart attack (myocardial infarction) - Low blood pressure (hypotension)

Question 60

What patients are at risk of collapse/heart attack/hypotension following heart disease/weak heart? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 60

Older patients

Question 61

Why wasn't the patient 'given a shot' or even asked to take any medicine immediately? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 61

By the time you get the medication out it may have gone into cardiac collapse

Question 62

How can you slow a SVT? | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 62

Carotid sinus massage - press and gently massage the carotid artery

Question 63

What does a carotid sinus massage do? Explain as if you were describing to a patient. (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 63

That sends a message to the heart to slow down by releasing some chemicals at the vagus nerve, and it stops the rhythm.

Question 64

How long do you need to perform a carotid sinus massage for? | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 64

A few seconds, then check whether the heart rate is back to normal.

Question 65

What are some contraindications before performing a carotid sinus massage? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 65

Doctors must check for clots that could rupture and could lead to stroke before doing the massage.

Question 66

Should you teach patients to be able to perform carotid sinus massages on themselves (if needed)? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 66

Some patients are taught to do it at home when their medications don't work.

Question 67

Can carotid sinus massages reduce length of hospital stays? | Clinical Presentation: SVT and Carotid Sinus Massage

Answer 67

If nothing else is wrong, patient's may be able to go home the next day!

Question 68

Question: Can you recall the ECG appearance of an SVT? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 68

Normal QRS complexes, but very narrow (i.e. rapid) > 150 bpm (Bpm calculated by 300/number of large squares in R-R interval e.g. 300/2 big squares = 150 bpm = tachycardia)

Question 69

Question: Can you explain why external massage over the carotid sinus can help terminate an SVT? (Clinical Presentation: SVT and Carotid Sinus Massage)

Answer 69

The carotid sinus is the location of baroreceptors, which allows for a procedure known as the carotid sinus massage. If a patient has a SVT (heart racing because of something happening above ventricles and atria) then you can slow conduction getting through AVN by increasing vagal tone. To increase vagal tone you can massage in the carotid triangle area to massage over the carotid sinus, activating baroreceptors, which will, in turn, enhance vagal input (parasympathetic drive to the heart), and therefore, slow down heart rate. (It may also be that in massaging this area the VN is there as well so you can directly stimulate VN)