Flashcards in H&N 3.1 blood vessels Deck (48):
what are the MAJOR blood vessels of the neck?
-common carotid artery
-internal jugular vein
-external jugular vein
Where does the thyrocewrvical trunk branch from?
The subclavian artery
Other than the thyrocervical trunk, what other branches come from the subclavian artery in the neck?
-internal thoracic artery
What are the branches of the thyrocervical trunk?
ascending and transverse cervical arteries
inferior thyroid artery
How do the vertebral arteries travel into the head?1
Via the transverse foreamina of the cervical vertebrae.
Whats the function of the vertebral arteries?
Blood supply to the brain (along with the ICA)
How does the ICA get into the skull?
Via the carotid canal.
At what level is hthe bifurcation of the common carotid artery?
the superior border of the thyroid cartilage.
Under what muscle does the common carotid run, and what vessel is found next to it?
Internal jugular vein runs laterally to it.
What is the carotid sinus?
What does it contain?
a swelling found on the internal carotid artery just after the bifurcation. Here you find stretch receptors known as baroreceptors.
What is the carotid body?
the location of peripheral chemoreceptors involved in control of O2.
What's clinically relevant about the bifurcation of the carotid artery?
It is a common site for atheroma, which could lead to embolus formation and therefore a stroke/TIA.
what is contained within the carotid sheath?
common carotid artery,
Internal jugular vein
deep cervical lymph nodes
the carotid triangle is a subdivision of which larger triangle in the neck?
The anterior triangle
What are the borders of the carotid triangle?
superior- posterior belly of diagastric
medial- superior belly of omohyoid.
What are the contents of the carotid triangle?
The bifurcation of the common cartid artery
Internal jugular vein
Why is the carotid triangle of clinical significance?
- access to the IJV and carotid arteries
-can access the vagus and hypoglossal nerves
-can feel carotid pulse
-carotid sinus massage
What is the carotid sinus massage?
Used when someone is tachycardic, you gently massage the carotid artery at the area of the carotid sinus. The baroreceptos interpret this as high blood pressure so decrease the heart rate accordingly.
When can you not do a carotid massage?
If someone is suspected to have atherosclerosis, it could lead to a thromboembolism and a stroke.
What are the branches of the external carotid artery?
What are the 2 terminal branches of the external carotid artery?
What are the 5 arteries associated with blood supply to the scalp? where do these originate from?
-occipital, posterior auricular, superficial temporal (branches of the ECA)
-supra-orbital, supra-trochlea (branches of the ICA)
What are the layers of the scalp in order?
-connective tissue (dense)
-aponeurosis (of the frontal and occipital)
-loose connective tissue
Where do the vessels of the scalp run?
In the subcutaneous, dense connective tissue layer
Why do laceration to the scalp lead to profuse bleeding?
-many anastamoses so rich blood supply
-if aponeurosis is involved, pulls apart and prevents contraction of the blood vessels
-walls of arteries closely attached to the connective tissue, so cannot constrict as much.
Will a laceration to the sclap affect blood flow to the skull?
No, the skull is supplied mainly by the middle meningeal artery, a branch on the ICA.
How do superficial veins drain the scalp?
Via following the arteries
how do the supra-trochlea and supra-orbital vein drain?
unite at medial angle of the eye to form the angular vein, which drains into the facial vein.
Name some venous sinus' of the head?
-superior saggital sinus
how are veins of the scalp and dural venous sinus' connected?
Via emmissary veins, which are valveless so allow blood to flow whichever way pressure permits. This allows for potential spread of infection.
Why is the middle meningeal artery at risk of damage?
it runs under the pterion, a weak point in the skull.
What complication can occur due to damage to the pterion?
a ruptured meningeal artery, which will bleed into the space between the periostium and the dura, leading to an extradural haemorrhage. This can lead to raised ICP, and deviation of the midline.
By what procedure do we access the cranial cavity?
What's unique about a craniotomy and why?
The bone and scalp flap are reflected posteriorly to maintain blood supply (which runs from inferior to superior)
What are the superficial arteries of the face?
lateral nasal artery
superior and inferior labial artery
What is a dural venous sinus?
an endothelium lined apce between the periosteal layers and the meningeal dural layers.
Whats the function of a dural venous sinus?
to recieve blood from large vessels draining the brain.
what vein is the sigmoid sinus closely related to? What is the relation?
The internal jugular vein, this is what the sigmoid sinus becomes.
What does the cavernous sinus contain?
-internal carotid artery
-opthalmic branch and maxillary branch of trigeminal nerve
-many thin walled veins
What venous plexus does the facial vein drain into?
pterygoid venous plexus.
What is thrombophlebitis?
an infected clot within a vein.
Whats the danger of thrombophlebitis of the facial vein?
It can travel to the intercranial venous system.
with regards to the SCM, where are the jugular veins?
The external jugular vein lies on top, the internal jugular vein lies underneith.
Which vein is a better indicator of right atrial pressure?
internal jugular vein.
How do you measure JVP?
Have the patient lying at 45 degrees.
Get them to turn their head to the left,
observe pulsations THROUGH the SCM.
measure the height of the pulsations from the sternal angle and add 5cm.
What is a raised JVP?
Greater than 3-4 cm above sternal angle.
What could a raised JVP indicate?