Lecture 3 - Blood Vessels Of Head And Neck Flashcards
What are the branches of the aortic arch from right to left? (look at end of lecture)
Brachiocephalic trunk (Right subclavian artery, right common carotid artery)
Left common carotid artery
Left subclavian artery
1 = right subclavian
2 = right common carotid
3 = brachiocephalic trunk
4 = left common carotid
5 = left subclavian
At what vertebral level do the common carotid arteries bifurcate into the internal and external carotid arteries?
C4
What is the bulge in the left carotid artery called?
Carotid sinus
What special cells are located in the carotid sinus?
What are their function?
Baroreceptors
Detect changes in blood pressure
What is the carotid body?
Where is it found?
Area between the internal and external carotid arteries
Which contains chemoreceptors which detect changes in blood 02, CO2 levels and pH
Why is the bifurcation of the common carotid artery a common site for atherosclerotic plaque development and why is this dangerous?
Turbulent blood flow at the point of bifurcation
Atherosclerotic plaque can rupture forming thromboemboli which can go into the internal carotid artery causing a stroke
What is the point of doing a carotid sinus massage?
Can be used to help determine types of arrhythmias
By massaging cartotid sinus stimulating the Baroreceptors it increases parasympathetic output to heart temporaliy terminating a suupraventricular tachycardia
What type of imaging is used to image the carotid arteries?
Carotid ultrasound
How does the external carotid artery travel?
What arteries does it terminate as?
As soon as the CCA birfurcates the ECA immediately exits the carotid sheath
Then it gives off 8 branches
Terminates as the superficial temporal artery and maxillary artery
What are 2 important branches of the maxillary artery?
Middle meningeal artery
Sphenopalatine artery
What does the sphenopalatine artery supply?
Nasal cavity (source for epistaxis = nosebleeds)
What does the middle meningeal artery supply?
The meninges, it enter intracranially
Where can the superficial temporal pulse by palpated?
Where does the superficial temporal artery run?
Soft skin in front of the ear
In front of ear to temple
What is the pneumonic used to remember the 8 branches in the order that they branch from the external carotid artery?
Some
Anatomists
Like
Freaking
Out
Poor
Medical
Students
Using the PNUEMONIC what are the 8 branches from first to last that come from the external carotid artery?
Some = Superior thyroid artery
Anatomists = Ascending pharyngeal artery
Like = lingual artery
Freaking = facial artery
Out = occipital artery
Poor = posterior auricular artery
Medical = maxillary artery
Students = superior temporal artery
What does the superior thyroid artery supply?
Thyroid gland
What does the lingual artery supply?
Tongue
Where does the facial artery supply and run?
The main artery of the face
Comes from behind the mandible to the corner of the eye running in front of the masseter muscle
Where does the occipital artery run to and supply?
Runs behind head to supply scalp
Where does the posterior auricular artery run and supply?
Runs behind ear to back of scalp
Where can you palpate the facial arterial pulse?
Inferior edge of mandible
What artery can be affected by temporal arteritis?
What is temporal arteritis?
What is the consequence of not picking it up?
Superior temporal artery
Inflammation of arterial wall
Can lose Visio due to an artery supplying eye gets affected
Where does the middle meningeal artery enter the skull?
Foramen spinosum
What area of the skull is the middle meningeal artery underneath?
Pterion
What can happen when if the middle meningeal artery gets ruptured and how does it appear on a CT head?
Extra dural haemorrhage
Lentiform appearance
How does the internal carotid artery run through the neck?
Runs up the neck through the carotid sheath till it reaches the base of the skill
Then at a right angle runs through the carotid canal which is inside the Petrous bone
Then exits the Petrous bone into the cavernous sinus
Exits cavernous sinus giving branches to the ophthalmic artery and branches of cerebral arterial circulation
What does the internal carotid artery branch into once its exited the cavernous sinus?
Ophthalmic artery
Branches supplying cerebral arterial circulation
What artery do the vertebral arteries branch from?
First branch of subclavian artery
What structure do the vertebral arteries run up the back of the neck which protects them?
Transverse foramina of C1 - C6
At what point do the vertebral arteries enter into the cranium?
At the posterior Atlanto-occipital membrane at C1 enter the Foramen magnum
What artery do the left and right vertebral artery join together to form?
Basilar artery
Label the cross section through the neck 1 - 11
1 = prevertebral cervical fascia
2 = thyroid gland
3 = carotid sheath
4 = superficial cervical fascia
5 = pre-vertebral cervical fascia
6 = buccopharyngeal fascia
7 = trapezius
8 = Sternocleidomastoid
9 = Internal jugular vein
10 = common carotid artery
11 = investing fascia
Where is the carotid triangle located?
In the anterior triangle
What are the superior, medial and lateral borders of the carotid triangle?
Superior = posterior belly of digastric muscle (suprahyoid muscle)
Medial = superior belly of omohyoid (infrahyoid muscle)
Lateral = sternocleidomastoid
What are the borders of the anterior triangle?
Medial = mid Sagittal line of neck
Roof = lower edge of mandible
Lateral = Sternocleidomastoid (anterior edge)
What anatomical feature has to be moved/reflected in order to see the digastric muscle (superior part of carotid triangle)?
Submandibular salivary gland
What is the importance of the carotid triangle?
Common carotid artery bifurcates in here
Carotid sheath can contents accessible here
What is a carotid endartectomy?
Incision made in neck at carotid triangle CCA and ICA incised and atherosclerotic plaque removed
What are the superficial veins of the face and scalp?
There are many but all the arteries in the face and scalp have a corresponding vein
What vessels do the facial vein communicate with?
Veins draining orbit and deeper structures of face
What forms the external jugular vein?
The veins draining the scalp and veins draining the deep face
Where does the external jugular vein run?
In the superfical cervical fasica on top of the Sternocleidomastoid
What vein does the subclavian vein drain into?
SVC
Where does the internal jugular vein emerge from and run?
Begins at jugular foramen (base of skull) as continuation of sigmoid sinus
Descends length of neck in carotid sheath deep to SCM receiving multiple veins en route
What does the internal jugular vein join up with/drain into?
Subclavian vein which leads to the brachiocephalic vein -> Superior vena cava -> right atrium
How can you measure Jugular Venous Pressure and what does it indicate?
Get patient to lie in bed at 45 degree angle on turn head/neck to the left
Then view height of pulsation from the internal jugular vein. Higher = higher pressure in the right atrium
What muscle can a central one be put between to access the internal jugular vein?
SCM
Why is the internal jugular vein used for central lines and not the subclavian vein?
Subclavian vein has a higher risk for pneumothorax
What veins drain the orbit?
Ophthalmic veins
What do the ophthalmic veins draining the orbit drain into?
Facial vein
+
Cavernous sinus (an intracranial venous structure)
What is the concern with the ophthalmic veins that drain the orbit draining into the cavernous sinus?
Its a route for orbital infections to spread intracranially
What does the facial vein and veins draining deep strucutres of the central face drain into?
Pterygoids venous plexus which then communicates with the cavernous sinus
What is the concern with the facial vein and veins draining deep strucutres of the central space communicating twitch the pterygoid venous plexus which communicates with the cavernous sinus?
Route for superficial infections of centra face and nasal cavity to spread intracranially
What is the danger triangle?
Part of face which has its venous drainage to the cavernous sinus
What is the cavernous sinus?
Venous structure inside the skull formed by the dura
Why is infection to the cavernous sinus bad?
Risk of cavernous sinus thrombosis
Meningitis
What are the muscles of facial expression?
Buccinator
Risorius
Occipitofrontalis
Orbicularis oculi (orbital and Palpebral)
Orbicularis oris (around mouth)
Zygomaticus major
