Session 1.1c - Lecture (General Organisation Of The Head And Neck) Flashcards
Lecture
Describe the major muscle groups of the head and neck (ILO)
Two broad categories:
Muscles of facial expression
Muscles of mastication
Describe the nerve innervation of the major muscle groups of the head and neck (ILO)
Facial expression = 5 branches of facial nerve
Mastication = branches of the trigeminal nerve
Describe the broad action of the major muscle groups of the head and neck (ILO)
Facial expression - dilator or sphincter muscles which pull your face in a certain way i.e. give you a facial expression
Mastication - act on temporomandibular joint to open or close your jaw
Describe the boundaries of the anterior triangle (ILO)
- The anterior edge of SCM (medial)
- Imaginary line down the midline (right down the mid-sagittal plane there is an imaginary line)
- Lower border of the jaw (mandible)
There is one on either side of the midline
Describe the boundaries of the posterior triangle (ILO)
- SCM (posterior/lateral border)
- Trapezius (anterior border)
- Clavicle (superior/middle 1/3 border)
There is one either side of the neck
Describe the boundaries of the carotid triangle (ILO).
- Medial/anterior border of SCM
- Lateral border of omohyoid (infrahyoid muscle)
- Inferior border of the posterior belly of the digastric muscle (suprahyoid muscle)
Identify the surface anatomy of the anterior triangle (ILO)
SCM, midline and jaw
Identify the surface anatomy of the posterior triangle (ILO)
SCM, traps and clavicle
Identify the surface anatomy of the carotid triangle (ILO)
SCM, omohyoid, digastric muscle
What are the important anatomical triangles in the neck?
Anterior, posterior and carotid triangles.
Why is it important to know about anatomical triangles of the neck clinically?
It can be helpful in determining where a neck lump may have originated from/how it arose.
Identify and describe the general anatomical organisation of neck structures when viewed in cross-section (ILO)
ILO
Recall the arrangement of neck structures within the cervical fascial layers (ILO)
Superficial -
Investing -
-
-
Recall the arrangement of neck structures within the cervical fascial layers and their relation to the anatomical triangles of the neck (anterior, posterior and carotid triangles) (ILO)
ILO
Have a look at the muscles as well
Understand the implications for the spread of deep neck space infections due to the compartmentalisation and boundaries of the cervical fascial planes (ILO)
ILO
Why are the cervical fascial planes important, and their clinical application in terms of potential spaces between these fascial planes where infection can collect, and why deep neck space infections are rare but quite concerning and potentially life-threatening.
How is the head organised into the face and scalp?
Face = eyebrows to chin Scalp = eyebrows to back of skull (occipital region)
What is significant about how the two broad groups of muscles of the head are divided?
Overview
They share commonalities in function and nerve supply.
What are the nerves and blood vessels of the face?
Overview
Will be touched upon in the next lecture
What are the key components of the neck?
Overview
Think about what’s in the neck, and how is it arranged
What are the neck muscles?
Overview
There are a lot of neck muscles but we’ll highlight the ones you really need to know and how they help form the boundaries of the anatomical triangles
Describe the anatomical triangles of the neck?
Overview
Describe the fascial compartments of the neck.
Overview
These help organise everything
What is the cranium?
Skull
What is another word for skull?
Cranium
How many bones of the skull are there?
22
What is the collective name for bones that surround the brain?
The neurocranium
What is the neurocranium?
A collective name for bones that surround the brain
What is the collective name for bones that surround the face?
The viscerocranium
What is the viscerocranium?
A collective name for bones that surround the face
What are the layers of skin that lie over the neurocranium and the viscerocranium?
The face and the scalp
Where is your scalp?
The scalp goes from your eyebrows right the way round to the back of the skull (occipital region)
Where is the occipital region of the skull?
At the back
Where is your face?
From the eyebrows to your chin
Where is your forehead?
Just above your eyebrows
What is interesting about the forehead?
It is shared between the scalp and face (despite eyebrow boundary)
Is the forehead part of the scalp or face?
Although the boundaries of the scalp/face are at the eyebrows, we still sometimes consider the forehead as part of your face as well.
Which part of the head overlaps in face and scalp?
The forehead
What does mastication mean?
Chewing
What do muscles of mastication do?
Act on the temporomandibular joint to open or close (move) the jaw
Mastication = chewing
The facial nerve and trigeminal nerves are what type of nerves?
Cranial nerves
What are cranial nerves?
Nerves that come from the brainstem
What nerve supplies the muscles of facial expression?
Branches of the facial nerve
What nerve supplies the muscles of mastication?
Branches of the trigeminal nerve
What do branches of the facial nerve supply?
The muscles of facial expression
What do branches of the trigeminal nerve supply?
Muscles of mastication
What is the main artery that supplies your face?
The facial artery
helpfully named
What is the main vein that supplies your face?
The facial vein
The facial artery mainly supplies what?
Your face
The facial vein mainly supplies what?
Your face
The facial blood vessels come from where?
They are branches of much bigger, important vessels found in the neck.
Where are the muscles of facial expression found?
In your face/scalp
They tend to attach to bits of bone, the other end to the skin/fascia (superficial fascia of the face) or even other muscles
What do muscles of facial expression do?
They are dilators or sphincter muscles which pull your face in a particular way to elicit facial expression
Roughly speaking, what type of muscles are your muscles of facial expression?
Dilators or ‘constrictors’
Where and how are the ‘constrictor’ muscles of the face arranged?
In a circular fashion around the orifices of the face (e.g. eyes, mouth etc.)
What is a sphincter muscle?
A circular muscle that maintains constriction of a natural body orifice
Give example of sphincter muscles.
The muscles around your eyes, mouth
- Generally found in orifices around body cavities
- If it’s a round-shaped muscle it’s going to act like a sphincter
What are dilator muscles?
Muscles that pull parts of the face or other muscles in a particular direction
How are dilator muscle fibres arranged?
Linearly
Broadly speaking, what is the function of the linearly-arranged and circular muscles of the face?
Linearly-arranged muscles are dilators which pull rather than constrict.
Circular muscles (sphincters) act to constrict.
(This is helpful to be aware of to appreciate what they’re doing to your face when you use them - relating structure to function)
Why are we able to create such a vast range of facial expressions?
- There is a huge variety of facial muscles
- They’re very much connected to the skin
How many muscles of mastication are there?
4
What joint do the muscles of mastication act on?
The temporomandibular joint (TMJ)
What is the temporomandibular joint?
The bit where your jawbone joins the rest of your skull.
What is the part where your jawbone joins the rest of your skull called?
The temporomandibular joint (TMJ).
Which cranial nerve are muscles of facial expression innervated by?
Cranial nerve VII (facial nerve)
Which cranial nerve is the facial nerve?
VII (7)
Which nerve is cranial nerve VII?
Facial nerve
Which cranial nerve are muscles of mastication innervated by?
Cranial nerve V (trigeminal nerve)
Which cranial nerve is the trigeminal nerve?
V (5)
Which nerve is cranial nerve V?
Trigeminal nerve
There are ____ key _____-_______ ________ (terminal) of the facial nerve.
There are five key extra-cranial branches (terminal of the facial nerve.
Define “extra-cranial branches of the facial nerve”?
Branches that have arisen from the facial nerve outside of the skull
What happens to the facial nerve when it branches in terms of extracranial or intracranial?
Some of these nerves become extra-cranial (terminal branches) - these have arisen from the facial nerve outside of the skull. This is just a little portion of the facial nerve!
A large portion of the facial nerve has remained through the bones of the skull, and there’s lots of branches that it gives off inside the skull as well.
Image (page 6):
Label the branches of the facial nerve
Temporal Zygomatic Buccal (Marginal) Mandibular Cervical
Where is the temporal branch of the facial nerve (roughly)?
Temporal i.e. temple
Indicates side of the head behind the eyes
Self-note: remember the location by the name.
What are muscles in your forehead supplied by?
The temporal branch of the facial nerve
(The temporal branch of the facial nerve runs up the temporal region towards your forehead, so you can work out that muscles in your forehead are supplied by the temporal nerve without having to specifically learn innervations for every muscle)
What is the zygoma?
A bone in your face that forms your cheek.
What is the bone in your face that forms your cheek called?
The zygoma
Where is the zygomatic branch?
It runs in close proximity to the zygoma (your cheekbone), hence the name.
What does buccal mean?
Cheek
What is another word for cheek?
Buccal
What is the cheek muscle called?
Buccinator (buccal = cheek)
Where is the buccal branch of the facial nerve?
It is the branch that goes to your cheek
What muscles does the buccal branch of the facial nerve supply?
Supplies muscles of the face in your cheek region
buccal = cheek
The mandibular branch’s full name is …?
Marginal mandibular
The marginal mandibular branch’s name can be shorted to …?
Mandibular
Where is the mandibular branch of the facial nerve?
Runs across the jaw, i.e. the mandible
Where is the cervical branch of the facial nerve?
It goes to your neck towards the platysma muscle
What is the platysma muscle?
A sheet-like muscle in the neck that lies in the superficial cervical layer. It is a muscle of facial expression despite being in your neck, and not the face.
Name the 5 extra-cranial branches of the facial nerve - you can use a mnemonic to remember them first.
To Zanzibar By Motor Car
Temporal Zygomatic Buccal Mandibular Cervical
*Think about their names to figure out their location and vice versa!
Where do most of your cranial nerves arise from?
Your brainstem
The cranial nerves need to travel from where to where?
The inside of your skull to the outside.
When the facial nerve comes out of your skull, where does it pass into?
The parotid gland (an important salivary gland)
Where does the parotid gland lie?
Just in front of and inferior to your ear
What is the gland anterior and inferior to your ear known as?
The parotid gland
The facial nerve runs through the substance of the parotid gland. What can this mean clinically?
If you have pathology, particularly malignant pathology of the parotid gland, patients may present with weakness of the muscles of that side of their face because you’re affecting the facial nerve.
Why do patients with parotid gland malignancy present with weakness to muscles of the ipsilateral side of their face?
The facial nerve runs through the substance of the parotid gland, so any pathology affects the facial nerve and therefore the muscles it innervates on that side of the face.
Image (page 6):
Which side of the face is this showing?
Right
How many facial nerves in the body are there?
2 - one on your left and one on your right side.
What do the left and right facial nerves supply?
The left facial nerve supplies all the muscles on the left-hand side of the face, and the superficial muscle of the neck. The right facial nerve mirrors this on the right-hand side.
The facial nerve has an important relationship with what gland?
The parotid gland
What is the main sensory nerve of your face and scalp?
The trigeminal nerve
How can we feel if someone tickles your forehead or touches your nose (i.e. which nerve)?
This is sensed by the branches of the trigeminal nerve taking that sensory signal back to your brain.
How many branches of the trigeminal nerve supply motor innervation?
Just the one (the rest all supply sensory, including this one), which carries the motor signals to the muscles of mastication. You can remember which division as it is the branch that’s heading in the direction towards the jaw that carries the motor innervation.
What are the three key branches/divisions of the trigeminal nerve (cranial nerve V)?
Va ophthalmic division
Vb maxillary division
Vc mandibular division
The ophthalmic division of the trigeminal nerve supplies what?
Sensory innervation to all of your forehead and most of your eye, including the front of your eye; your conjunctiva and cornea.
Your forehead is supplied by which nerve?
Ophthalmic division of the trigeminal nerve
The front of your eye is supplied by which nerve?
Ophthalmic division of the trigeminal nerve (opthalmic = eye)
Your conjunctiva is supplied by which nerve?
Ophthalmic division of the trigeminal nerve
Your cornea is supplied by which nerve?
Ophthalmic division of the trigeminal nerve
What can the ophthalmic nerve be abbreviated to?
Va
V = cranial nerve V (facial nerve) a = first sub-division of cranial nerve V
Image page 4:
Label the neurocranium
Image
Image page 4:
Label the viscerocranium
Image
Image page 4:
Label the cranium
Image
Image page 4:
Label the sutures
Image
Image page 4 (bottom):
Label the scalp
Image
Image page 4 (bottom):
Label orbicularis oculi
Image
Image page 4 (bottom):
Label orbicularis oris
Image
Image page 4 (bottom):
Label the face
Image
Image page 4 (top):
Which view is this?
Lateral aspect
Image page 5:
Label a sphincter muscle
Orbicularis oculi
Image page 6:
Label the 5 branches of facial nerves
Temporal Zygomatic Buccal Mandibular Cervical
Where does the maxillary division of the trigeminal nerve lie?
It sits near the maxilla bone, so in the cheek region.
What can the maxillary division of the trigeminal nerve be abbreviated to?
Vb
What is the full name of the Vb division of the trigeminal nerve?
The maxillary division
After ophthalmic and maxillary, what is the final third key branch of the trigeminal nerve?
The mandibular division
*Note: do not confuse with mandibular branch of FACIAL nerve! When talking about facial nerve it may be easier to refer to as marginal mandibular to prevent confusion with branches of the trigeminal nerve.
Which nerve gives rise to motor fibres to muscles of mastication?
The mandibular division of the trigeminal nerve
*Think - branch is going that way, so it makes sense that motor fibres that are carrying that branch to get to muscles that are all down there and moving the jaw.
What is significant about the mandibular division of the trigeminal nerve (compared to the other divisions)?
It gives rise to motor fibres to muscles of mastication (the others are only sensory innervation)
What can the mandibular division of the trigeminal nerve be abbreviated to?
Vc
Which division of the trigeminal nerve is also known as Vc?
The mandibular division
What supplies the main sensory sensation from the face?
The trigeminal nerve
What supplies the motor innervation to the muscles of mastication?
The mandibular division of the trigeminal nerve
What does the trigeminal supply?
The main sensory sensation to the face, and the mandibular division supplies the motor innervation to the muscles of mastication.
How do we test the function of the trigeminal nerve?
We touch the face of the person but within the dermatomal distribution to check each branch (ophthalmic, maxillary, mandibular). This occurs on both sides because one half will be the right trigeminal and the other half the left trigeminal
Why do we touch the face of the person within dermatomal distributions when testing the function of the trigeminal nerve?
To check each branch is working
Why do we test both sides of the face when testing the function of the trigeminal nerve?
Because each half is supplied by the corresponding nerve i.e. the right half is supplied by the right trigeminal.
What is the main arterial supply to the head and neck?
The common carotid artery via its terminal branches (internal and external carotid arteries)
What two arteries does the common carotid artery split into?
The internal and external carotid arteries
Where does the CCA split into two arteries?
Further up the neck, above C4
The internal and external carotid arteries are branches of which artery?
The common carotid artery
Does the internal carotid artery give off any branches?
No, it goes straight up to the base of the skull and does stuff there.
Which of these does not give off any branches, the internal or external carotid arteries?
Internal carotid artery
Where does the internal carotid artery go?
It goes straight up into the base of the skull and supplies structures in the skull
Which of these arteries give off further branches - internal or external carotid artery?
The external carotid artery
Which artery supplies the tissues of your face?
The facial artery
Where does the facial artery arise from?
The external carotid artery (which is a branch of the common carotid artery)
What does the external carotid artery do?
It gives off branches that supply the tissues of the neck and face
Where does the facial artery run?
It runs up your face towards the medial part of your eye
Which artery runs up your face towards the medial part of your eye?
The facial artery
How can you palpate your facial artery?
At the edge of your jaw - clench your teeth where you feel the masseter bulk up on your jaw - just in front of that muscle as it’s clenched, you’ll feel the pulse of the facial artery as it’s running over the edge of the bone.
How can you palpate the masseter muscle?
Clench your teeth and feel your jaw - that is the masseter muscle
Where can you palpate the facial artery in relation to the masseter?
Just in front of the masseter
Where does the facial artery come from?
The ECA as it comes up through the neck.
Where does venous drainage from the face go?
It has to get away from the face back to the heart
Which vein does the head and neck drain from?
The facial vein
Where does the facial vein run in relation to the facial artery?
In exactly the same direction as the facial artery (but obviously going into a different direction)
Where does the facial vein drain into?
Ultimately into the internal jugular vein
What drains into the internal jugular vein?
The facial vein
Do the facial artery and vein generally run superficially or deep to a lot of the face muscles?
Deep
What is the route of the facial vein (and artery)?
From the medial angle of the eye, it runs to the edge of the mandible, where it leaves the head and drains into other venous structures that are much deeper inside the neck.
The facial vein drains into structures inside the neck. Are these superficial or deep?
Deep
What is the main vein draining head and neck structures?
The internal jugular vein (IJV)
What does the IJV do?
It is the main vein draining head and neck structures
What does the IJV receive?
Venous drainage from the face (facial vein)
Where can we find the external jugular vein in comparison to other structures?
Quite superficially
Which vein can you see quite superficially in the neck?
External jugular vein
Which vein is quite regularly seen in the neck when you’re angry or tensing?
The external jugular vein
The external jugular vein can be seen in the neck. When can the EJV be seen more prominently?
When you’re angry, tensing or anything that increases thoracic pressure
What does the external jugular vein receive?
Along with the IJV, it also receives veins draining from the scalp and face
Which runs more superficially, the external jugular vein or internal jugular vein?
EJV
Note: think external
Which runs more deep, the external jugular vein or internal jugular vein?
IJV
Note: think internal
What is your face?
Boundaries
What is your scalp?
Boundaries
What are some of the muscles that we can broadly think about?
- Function
- Innervation
Describe
What structures does the neck have running up the length of it?
Nerves and blood vessels
How far do nerves and blood vessels run up the neck?
Along the length of it
What do the nerves and blood vessels of your neck do?
Run up the length of the neck, and therefore feed structures in your face and brain
The veins will also be draining structures of your face/brain/neck to return them to the heart.
What are the bony structures found in your neck?
Cervical vertebrae