3. Major Blood Vessels of Head and Neck Flashcards
What are the 3 branches of the arch of the aorta?
◦ brachiocephalic trunk
◦ left common carotid artery
◦ left subclavian artery.
What are the branches of the brachiocephalic trunk?
bifurcates into the right common carotid artery and right subclavian artery
What are the 4 branches of the right subclavian artery?
vertebral, internal thoracic, thyrocervical trunk, costocervical trunk
What are the 4 branches of the thyrocervical artery?
Suprascapular, transverse and ascending cervical, inferior thyroid
What is the inferior thyroid artery a branch of and what does it supply?
thyrocervical trunk, supplies lower pole of thyroid gland
Which structure does the inferior thyroid artery run close to?
recurrent laryngeal nerve - have to be careful when doing thyroid surgery
What do the vertebral arteries originate from and what do they supply?
Originate from the subclavian arteries. Supply posterior neck and posterior parts of the brain (e.g. brainstem, cerebellum)
What is the path of the vertebral arteries and what do they join to form?
Ascend through transverse foramen of cervical vertebrae (except C7), enter cranium from foramen magnum, curve anteriorly around medulla and join to form basilar artery.
Which arteries from circle of willis?
Internal carotid artery anteriorly and basilar artery posteriorly
Where do the common carotid artery originate from?
right - Brachicephalic artery, behind the sternoclavicular joint,
left - directly from arch of aorta
What is the arrangement of neurovasculature in carotid sheath?
Common carotid medial, IJV lateral, Vagus nerve between and behind
Where does the common carotid artery most commonly bifricate?
Upper border of the thyroid cartilage (C4). - carotid sinus
Why is the internal carotid artery more bulbous at the bifurcation of the common carotid?
Carotid sinus (and carotid body)
What is the clinical importance of the carotid sinus?
Can alleviate supraventricular tachycardia i.e. carotid massage
What do the carotid sinus/body detect?
Sinus: changes in arterial BP - contain baroreceptors
Body: detect arterial O2
What does the common carotid artery bifricate into?
internal carotid artery
external carotid artery
How many branches does the internal carotid artery have in the neck?
None
Where does the ICA enter the skull?
Carotid canal in petrous part of temporal bone
What bone does the ICA sit on after entering rhe skull and what structure does it pass?
Sphenoid bone, passes cavernous sinus.
What is the cavernous sinus?
Plexus of thin walled veins at either side of sella turcica
What structures are found in the cavernous sinus
◦ Internal Carotid artery ◦ CN III (Oculomotor) ◦ CN IV (Trochlear) ◦ CN VI (Abducens) ◦ 2 branches of CN V (Trigeminal) ( CN V1 ophthalmic and CN V2 maxillary)
What structure forms the superior border of the carotid triangle?
posterior belly of digastric muscle
What structure forms the medial/inferior border of the carotid triangle?
superior belly of omohyoid muscle
What structure forms the lateral border of the carotid triangle?
medial border of SCM
what is the importance of the carotid triangle?
- Bifurcation of the common carotid occurs within
the carotid triangle - Contains clinically important artery - carotid
◦ Atherosclerosis
◦ Carotid sinus massage
◦ Central pulse - Access site for vagus and hypoglossal nerves
- Contains internal jugular vein
◦ Access site for central line placement
what is the bifurcation of common carotid a common site of?
atherosclerosis
describe what happens in atherosclerosis of bifurcation of common carotid
◦ Causes the artery to narrow (stenose)
◦ Plaque rupture can release an embolus which can travel to the brain
◦ Can cause a stroke or TIA depending on the size
◦ Can also course transient loss of vision (Amaurosis
Fugax)
what is Carotid endarterectomy
◦ Incision in to the neck and the carotid
◦ Removal of plaque tissue and stitched back up
describe the carotid sinus massage
◦ Pressure at the site of the carotid bodies
◦ Increased baroreceptor activity feedback to the heart to slow down
which vein is a good site for central venous line?
IJV -
Large central vein
Superficial
Easily accessible
What is the ophthalmic artery a branch of?
internal carotid artery
What are 3 major branches of the ophthalmic artery?
Supraorbital, supratrochlear, central retinal artery
what is the first branch of ICA?
ophthalmic
what other branches of ICA provide arterial blood to brain?
◦ Anterior cerebral artery
◦ Middle cerebral artery
◦ Posterior communicating artery
How many branches does the ECA have and what mnemonic is used to remember them?
8 Some Anatomists Like Freaking Out Poor Medical Students
what are the branches of the ECA
Some – Superior thyroid Anatomists – Ascending pharyngeal Like - Lingual Freaking - Facial Out - Occipital Poor – Posterior auricular Medical - Maxillary Students – Superficial Temporal
what are symptoms of Giant cell arteritis (GCA) / Temporal arteritis?
◦ Frequent, severe headaches
◦ Scalp tenderness particularly over the temple
◦ Jaw pain while eating/talking
◦ Loss of vision/visual changes
without treatment, what can Temporal arteritis lead to?
Without treatment patients can permanently lose their eye sight
What is temporal arteritis?
Inflammation of superficial temporal artery (1/8 branch of external carotid)
Which blood vessels supply the scalp?
ICA: supraorbital, supratrochlear.
ECA: Superficial temporal, posterior auricular, occipital.
They have rich anastamoses
Name the layers of the scalp? (Hint : acronym SCALP)
skin connective tissue aponeurosis loose areolar tissue periosteum
In which layer of the scalp are the vessels located?
Dense connective tissue layer
Why does the scalp bleed heavily when cut?
◦ Artery walls held open by connective tissue and so cant constrict
◦ Lots of anastomoses
◦ Lacerations deep enough to involve the epicranial aponeurosis of occipitofrontalis can pull cuts open
What are the superficial arteries of the face?
from ICA:
Supraorbital art.
Supratrochlear art.
from ECA: Transverse facial art. Angular art. Lateral nasal art. Maxillary art. Superior & Inferior Labial art. Facial art.
What are the branches of the facial artery?
Submental, Inferior labial, Superior labial, Lateral nasal, Angular artery
What are 2 major branches of the maxillary artery?
◦ Middle Meningeal art.
◦ Sphenopalatine art.
what is the maxillary artery branch of?
ECA
what does the maxillary artery supply?
deeper facial structures
Through what structure does the middle meningeal artery enter the skull?
Foramen spinosum
The middle meningeal artery splits into anterior and posterior branches - what area of the skull does the anterior pass under?
Pterion
What part of the skull does the middle meningeal artery supply?
Dura mater of skull
Why is it easy to rupture the medial meningeal artery?
Anterior branch runs under PTERION -thin area of bone so fracture at this site can rupture MMA.
Rupture of the MMA (due to fracture of pterion) can lead to what life threatening condition?
Intracranial haemorrhage - called an extradural haemorrhage. - periosteal dura ripped away from bone and fill with blood
Needs surgical treatment. Puts pressure on brain
what is extradural haemorrhage management?
◦ Needs specialist neurosurgical treatment
◦ Craniotomy – opening of the cranium to relieve the pressure
◦ Evacuate the clot forming and stop the bleeding
Which arteries contribute to blood supply to the nasal septum?
Septal branch of sphenopalatine artery, Anterior/Posterior ethmoidal arteries, septal branch of superior labial artery
What is the Kiesselbach area?
Area in anterioinferior nasal septum where arteries anastamoses. Common site for nose bleeds
where do brain structures drain into?
dural venous sinus
where does the scalp drain into and how?
Scalp drains via emissary veins through the skull into dural venous sinuses
Because the scalp drains into dural venous sinuses, what does this lead of a risk of?
Infection ie meningitis
describe the venous drainage of scalp via external jugular vein
superficial temporal vein comes down and joins with occipital vein to form retromandibular vein which joins with posterior auricular vein to form external jugular vein that drains into subclavian vein
describe superficial venous drainage of the face
supraorbital and supratrochlear veins Unite at the medial angle of the eye to from the angular veins and drain into the facial vein which forms common facial vein, which drains into the internal jugular vein
The cavernous sinus is connected to ……… ……… plexus?
pterygoid plexus
Where is the pterygoid plexus located?
Infratemporal fossa
Which veins drain into the pterygoid plexus?
Paired veins of the branches of the maxiallary artery e.g. middle meningeal veins, sphenopalatine veins, etc.
Where does the pterygoid plexus drain?
Maxillary vein, which joins with the superficial temporal vein to form the retromandibular vein which drains into the external jugular vein
Where is the cavernous sinus located?
Either side of sella turcica
Which veins drain into the cavernous sinus?
Paired veins of the branches of the ICA artery e.g. superior and inferior ophthalmic veins, etc.
what is the association of facial veins and cavernous sinus??
Drainage of some structures into the cavernous sinus
Risk of infection to the intracranial cavity as directly connected
Where does the cavernous sinus drain?
Drain via superior and inferior petrosal sinuses into the the transverse sinus and sigmoid sinus which continue as the internal jugular vein
Do veins of the face have valves?
No
What is the danger triangle of the face, what is the clinical significance?
The region where the facial vein can drain backwards into the cavernous sinus
Infections in that area can spread via the facial vein and ultimately end up in the dural venous sinuses.
Could cause cavernous sinus thrombosis, meningitis or brain abscess
Which IJV gives indication of pressure in right atrium?
Right, has direct connection to right atrium. Left IJV joins with subclavian vein
how is jugular venous pressure measured?
Patient at 45 degrees
Head turned slightly to the left IJV mostly hidden by
sternocleidomastoid
Look for pulsations through the muscle
Measure the height from the sternal angle and add 5cm, gives an estimate of the right atrial pressure in cmH2O
