4) Major Blood Vessels Flashcards
Which arteries provide the main supply to the head?
Common carotid and vertebral arteries
Which arteries provide the main blood supply to the neck?
Thryocervical trunk: Inferior thyroid artery Ascending cervical artery Transverse cervical artery Suprascapular arteries
Where do the vertebral arteries arise from?
Subclavian artery
What structures do the vertebral arteries travel through?
Transverse foramina of C1-6
Foramen magnum
What happens to vertebral arteries when in the skull?
Join with vertebral artery from other side to form basilar artery
What is the Circle of Willis?
Anastomosis in brain formed from basilar and internal carotid arteries
Where does the common carotid artery bifurcate?
Level of superior border of thyroid cartilage (C4)
in carotid triangle
What are located at the carotid bifurcation?
Carotid sinus - baroreceptors
Carotid body - peripheral chemoreceptors
What are the consequences of hypersensitive baroreceptors?
External pressure of carotid sinus causes decrease in HR and BP, brain underperfused = syncope
Why is the carotid bifurcation a common site of atheroma formation?
Swelling due to carotid sinus causes turbulence of flow
By what procedure can a carotid atheroma be removed?
Carotid endarterectomy
What are the consequences of a carotid atheroma?
Rupture leading to embolus and TIA/stroke
What are the boundaries of the carotid triangle?
Superior - posterior belly of digastric
Lateral - SCM
Medial - Superior belly of omohyoid
What is contained in the carotid triangle?
Common carotid artery
Internal jugular vein
Hypoglossal and vagus nerves
What is the importance of the carotid triangle?
Surgical approach to carotid, IJV or vagus nerve
What is a carotid massage and why is it performed?
Stimulation of baroreceptors to decrease HR, relieving supraventricular tachycardia
What are the terminal branches of the external carotid artery?
Superficial temporal artery and maxillary artery (deep)
What are the 6 branches of the external carotid artery?
Superior thyroid Lingual Facial Ascending pharyngeal Occipital Posterior auricular
Where does the external carotid artery terminate?
Parotid gland
How does the internal carotid artery enter the cranial cavity?
Via carotid canal in petrous part of temporal bone
What does the internal carotid artery supply?
Brain, eyes, forehead
Which artery supplies the dura mater and the skull?
Middle meningeal artery
What procedure allows access to the cranial cavity?
Craniotomy, bone and scalp reflected inferiorly to preserve blood supply
Where can the facial artery pulse be felt?
Inferior border of mandible, anterior to masseter muscle
How can infection spread from scalp to meninges?
Through valveless emissary veins between veins of scalp and diploic veins of skull
What are dural venous sinuses?
Endothelial lined spaces between periosteal and meningeal layers of dura
What are the cavernous sinuses?
Plexuses of thin walled veins on lateral aspect of sphenoid bones. Receive blood from superior and inferior ophthalmic veins
What structures are found in the cavernous sinus?
Internal carotid artery and cranial nerves
Where do deep facial veins drain into?
Pterygoid venous plexuses
Why are veins of face susceptible to spread of infection?
Valveless so blood can flow in either direction
What veins drain into the external jugular vein and into which vein does EJV drain?
Posterior auricular, retromandibular and superficial temporal
Into subclavian vein
What vein drains the anterior neck?
Anterior jugular veins
How does the internal jugular vein begin?
Continuation of sigmoid sinus
Describe the route of the IJV to atrium:
Exits via jugular foramen into carotid sheath, lateral to artery. Combines with subclavian to from brachiocephalic vein
Into which vein does the facial vein drain into?
IJV
How should the JVP be measured?
Patient at 45 degree angle, height from sternal angle + 5cm, pulsations through SCM
What side is used to measure JVP and what does this show?
Right IJV, as direct communication to RA, so estimates pressure
What is a thrombophlebitis?
Infected clot into intracranial venous system
