Blood Supply Flashcards
Does the EJV lie posterior or anterior to SCM
Anterior
Where does bifurcation of common carotid happen
C4/ superior border of thyroid cartilage
What are the borders of the carotid triangle
Posterior belly of digastric
Superior border of omohyoid
Medial border of SCM
Why is carotid triangle important
Contains bifurcation of common carotid
Central pulse
Carotid sinus massage
Access for IJV - central line
Where is atherosclerosis common
At bifurcation
Plague can rupture and send embolus to brain = stroke TIA or amaurosis fugax
What is a carotid endarterectomy
Removal of plaque tissue and stitched back up
What does a carotid sinus massage do
Increase baroreceptor activity feedback to heart to slow it down
How many branches does the internal carotid artery give off in the neck
None- trick question
Where does the internal carotid enter skull
Carotid canal
Where do vertebral arteries enter brain and how do they get to it
Up through transverse foramina and through foramen magnum
Where is the carotid canal found
Petrous part of temporal bone
After the carotid canal where does ICA go
Cavernous sinus
What is the cavernous sinus and where is it found
Venous type structure on upper surface of sphenoid bone
What else runs through cavernous sinus
Carotid artery
CN 3,4,6,V1,V2
What is the 1st branch of the ICA
Ophthalmic
Other branches of ICA
Anterior cerebral
Middle cerebral
Posterior communicating
Forming anterior circulation of circle of willis
Branches of ECA
SALF
Superior thyroid
Ascending pharyngeal
Lingual
Facial
Branches of ECA
OPMS
Occipital
Posterior auricular
Maxillary
Superficial temporal
What are the terminal arteries of ECA
Maxillary
Superficial temporal
Why is the superficial temporal clinically important
Giant cell arteritis
Temporal arteritis
Headaches Jaw pain Loss of vision Scalp tenderness T: steroids
Blood supply to scalp
ICA: Supraorbital Supratrochlear ECA: Superficial temporal Posterior auricular Occipital
Layers of scalp
Skin Connective tissue dense- vessels Aponeurosis Loose areolar tissue Periosteum
Why does the scalp bleed heavily
Artery walls held open by CT so can’t constrict
If involve aponeurosis of occipitofrontalis then it pulls cut open
Maxillary artery of ECA branches
Middle meningeal- dura mata
Sphenopalatine- nasal
Where does the MMA enter skull
Foramen Spinosum
Anterior section passes under pterion
Significance of MMA rupture
Pterion fracture Middle meningeal artery rupture Haematoma Unsticks periosteal layer of dura but stops at suture lines Extradural haemorrhage
EJV venous drainage
Superficial temporal Occipital Supraorbital Supratrochlear Facial
Drainage of scalp and brain into
Brain into dural venous sinuses
Scalp drains via emissary veins to sinuses
Face drainage and implications
From superior and inferior ophthalmic.
Into cavernous sinus and pterygoid plexus
Hence risk of intracranial infection as directly connected
What is the danger triangle
Region where facial veins can drain backwards into cavernous sinus.
Via facial vein to dural venous sinuses
Name the dural venous sinuses
Superior sagittal
Inferior sagittal
Sigmoid
Transverse
What does the cavernous sinus drain into
IJV
How to measure JVP
Right side more direct path 45 degrees Head to left Pulsations Measure height from sternal angle 3cm = elevated Add 5cm Gives estimated cmH2O
