S3) Major Blood Vessels of the Head and Neck Flashcards
What is the anatomical surface landmark that relates to the dotted line A-B in the image below?
Angle of Louis (manubrio-sternal angle)
Name the components of the aorta illustrated as H, I and J
- H – ascending aorta
- I – aortic arch
- J – descending aorta
Name the blood vessels labelled C, D, E, F and G
- C – Brachiocephalic trunk
- D – Right common carotid artery
- E – Right subclavian artery
- F – Left common carotid artery
- G – Left subclavian artery
Which arteries arise from the brachiocephalic trunk on the right hand side?
Subclavian and common carotid arteries
Which arteries arise from subclavian artery in the base of the neck?
What are the branches of the thyrocervical trunk?
- Suprascapular artery
- Ascending cervical artery
- Inferior thyroid artery
- Transverse cervical artery
Which region does the suprascapular artery supply?
Suprascapular artery supplies the shoulder
Which region do the ascending and transverse cervical arteries supply?
Ascending cervical and transverse cervical arteries supply the neck
Which region does the inferior thyroid artery supply?
Inferior thyroid artery supplies lower pole of the thyroid gland
Where do vertebral arteries arise from?
Vertebral arteries arise from the subclavian arteries on left & right
Describe the course of the vertebral arteries through the brain
- Ascend in the neck through transverse foramina in C1-6
- They pass through the foramen magnum
Describe how the vertebral arteries supply the brain
The vertebral arteries supply the brain along with the internal carotid arteries which enter the skull through the carotid canal
Which arteries arise from the common carotid artery?
Common carotid artery bifurcates to give external and internal carotid arteries
Where does the common carotid bifurcate?
The common carotid bifurcates at about the level of the superior border of the thyroid cartilage
Describe the anatomical position of the internal jugular vein
The internal jugular lies lateral to the common carotid mostly under sternocleidomastoid
Bifurcation of the carotid artery is a common site for atheroma formation.
What are the consequences of this?
- Causes stenosis of the artery
- Rupture of the clot can cause an embolus to travel to brain (TIA or stroke)
What is the carotid sinus and what does it do?
- Carotid sinus is a swelling at region of bifurcation
- Location of baroreceptors for detecting changes in aBP
What is the carotid body?
Carotid body is a group of peripheral chemoreceptors which detect arterial O2
Which neurovascular structures can be accessed through the carotid triangle?
- Carotid arteries
- Internal jugular vein
- Vagus nerves
- Hypoglossal nerves
Which pulse can be felt in the carotid triangle?
Carotid pulse can be felt in carotid triangle just below bifurcation
What is the carotid sinus massage and what does it do?
- The carotid massage involves gently massaging the carotid artery
- Pressure in the area of carotid sinus quickly reduces heart rate (alleviates supra-ventricular tachycardias)
Describe the course of the internal carotid artery through the head and neck
- Enters skull through carotid canal
- Turns medially and horizontally
- Enters the cranial cavity then bends (S-shaped) to course through the cavernous sinus
What is the cavernous sinus?
Cavernous sinus is a plexus of extremely thin-walled veins on upper surface of sphenoid
Identify 6 neurovascular structures in the cavernous sinus
The ophthalmic artery branches from the internal carotid artery.
Identify its two main branches
- Supratrochlear artery
- Supraorbital artery
Identify the 6 branches of the external carotid artery
- Facial
- Lingual
- Occipital
- Ascending pharyngeal
- Posterior auricular
- Superior thyroid
Identify the two terminal branches of the external carotid artery
- Superficial temporal
- Maxillary
Describe the nature of the blood supply to the scalp
- Rich blood supply with many anastomoses
- Largely branches of external carotid artery
Describe the anatomical position of scalp blood vessels
Vessels of the scalp lie in the subcutaneous connective tissue layer
Where does the skull get its blood supply from?
Why is this significant?
- Mostly middle meningeal artery, the terminal branch of the maxillary artery
- Hence, loss of blood from scalp does not lead to bone necrosis
What are the consequences of a rupture to the skull?
Fracture of skull at pterion can cause the middle meningeal artery (supplies skull and dura) to rupture i.e. extradural haemorrhage
Where do the superficial arteries of the face arise from?
- All arise from the external carotid artery
- Exception: supra-orbital and supratrochlear artery arise from internal carotid artery
Where can the facial pulse be felt?
Facial artery pulse can be felt at inferior border of mandible, anterior to the masseter muscle
Identify the two most important branches in the nasal septum
- Septal branch of sphenopalatine artery (from maxillary artery)
- Anterior ethmoidal arteries (from ophthalmic artery)
Why is the Kiesselbach area in the nasal septum a common site for epistaxis?
- Anastomosis of arteries in Kiesselbach area
- Hence prone to nose bleeds
What is a craniotomy and how is it performed?
- Craniotomy is a procedure used to gain access to cranial cavity
- The bone and scalp flap are reflected inferiorly to preserve blood supply
Identify the 3 superficial veins draining the scalp
- Superficial temporal veins
- Occipital veins
- Posterior auricular veins
Describe the structures involved in the venous drainage of the scalp
- Supraorbital and supratrochlear veins unite at medial angle of eye to form angular vein (drains into the facial vein)
- Deep parts of scalp in temporal region have veins which drain into the pterygoid venous plexus
What is unique attribute of facial veins?
Veins of the face are valveless
Describe the drainage of the facial vein
At medial angle of eye the facial vein communicates with superior ophthalmic vein and drains into the cavernous sinus
Describe the clinical significance of the deep facial veins draining into pterygoid venous plexus
- Infection from facial vein can spread to dural venous sinuses
- Infected clot can travel to intracranial venous system i.e. thrombophlebitis of facial vein
What is the danger of the triangle of the face?
Infections in this region of the face can spread through the venous system to the dural venous sinuses
The sigmoid sinus is a dural venous sinus.
Describe its anatomical course
The sigmoid sinuses continue as the internal jugular veins, leaving the skull through the jugular foramina
Why is the external jugular vein easier to see?
The internal jugular vein lies under sternocleidomastoid
The internal jugular vein is a better indication of pressure in the right atrium.
How is this measured?
- Right IJV used
- Pulsations observed through muscle
- Measured in cmH2O
- Height from sternal angle + 5cm
Why might a doctor wish to listen over the carotid artery with a stethoscope?
- Check for degree of stenosis
- Listening for carotid bruit (systolic sound indicating turbulent blood flow)
Why is it helpful for a patient to hold his/her breath during auscultation of the carotid arteries?
Noise of breathing disrupts transmittent sounds
Name the holes in the base of the skull through which the following vessels travel:
- Internal carotid artery
- Internal jugular vein
- Middle meningeal artery
- Vertebral artery
- Internal carotid artery: carotid canal
- Internal jugular vein: jugular foramen
- Middle meningeal artery: foramen spinosum
- Vertebral artery: foramen magnum
