Session 2 Flashcards
Describe main arteries of the neck on the right. Look at diagrams after.
Brachiocephalic splits into subclavian and common carotid. CC has know branches until it bifurcated at C4 (superior border of thyroid cartilage) level into internal and external common carotid.
Subclavian has important branches coming from it such as internal thoracic, vertebral artery and inferior thyroid. The thyrocevical trunk is key.
Main arteries coming of thyrocervical trunk?
Inferior thyroid artery.
Ascending and transverse cervical.
Suprascapular for shoulder.
Describe the route of the vertebral artery
Passes through the transverse foramina C6-C1, then passes not the skull via the foremen magnum. The 2 vertebral arteries join to form the basilar artery. They can supply the brain.
Does the internal carotid give of branches and how does it enter the skull?
No.
Via the Carotid canal through petrous part of temporal bone. Then courses through the cavernous sinus.
Which is more medial the internal or external carotid artery?
The external
Borders of the carotid triangle and what does it contain?
Internal jugular vein laterally, common carotid artery and bifurcation and vagus nerve.
Anterior sternocleidomastoid, sup belly of omohyoid and post belly of digastric.
Clinical relevance to bifurcation of common carotid?
Due to turbulence a thermos and stenosis can occur limiting blood to brain of embolus to brain.
2 important features at the CCA bifurcation?
Carotid sinus-contains baroreceptors to detect Arterial BP.
Carotid body-contains chemoreceptors to detect o2 levels.
Clinical relevance of carotid triangle?
Vagus nerve accessible, carotid pulse, carotid/IJV surgery.
Importantly carotid massage-in VT can gently massage putting pressure on baroreceptors so seams like high arterial BP. Will then try and lower via vasodilation (decreased sympathetic on a1) and bradycardia (increase parasympathetic on m2)
What is the cavernous sinus?
Plexus of thin walled veins on upper surface of the sphenoid. Internal carotid artery and cranial nerves 3,4,5,6 pass through
Ophthalmic artery comes of the? And what branches does it give?
Internal carotid artery.
Ophthalmic gives ant/post ethmoidal arteries. Supra-orbital artery and supratroclear artery.
6 branches and two terminal branches of external carotid artery?
Superficial temporal (terminal) Superior thyroid Ascending pharyngeal Occipaital Posterior auricular Lingual Facial Maxilarry (terminal)
Describe blood supply to the scalp
Rich with many anastomoses
2 internal carotid- supra-orbital and supra trochleal
3 external carotid- occipital, superficial temporal, posterior auricular
Layers of the scalp? And what layer contains vessels of the scalp?
SCALP
Skin DCT (vessels) Aponeurosis LCT Periosteum
3 reasons why the scalp gets profuse bleeding?
Why no bone necrosis to skull if scalp arteries damaged?
Full of anastomoses, artery walls close the CT limiting constriction and occiptalfrontalis contracts on both sides of injury causing bleeding due to opposing pull.
Because middle meninges artery mainly supplies the skull.
Describe superficial arteries of face again use images.
Two internal (supras) Maxillary Labial (sup/inf) Facial Transverse facial Lateral nasal Angular
2 important branches of maxillary?
Middle meningeal and septal branch of sphenopalatine (nose bleeds)
Arterial supply to nasal area?
Different branches form kiesselbach area most importantly formed from sphenopaletine and ethmoidal. Area is common sight for epistaxis.
Main blood supply to skull/dura? how does it enter the skull And relevance of pterion?
Middle meningeal enters via foremen spinosum.
Pyerion is thin part of skull thus rupture common.
What happens if middle meningeal rupture?
Extradural haemorrhage
Describe drainage of Supra orbital/trochlear veins
Drain into angular vein at medial angle of eye which then drains into facial vein (labial veins do the same) then into the common facial vein into the IJV. Other veins tend to accompany there arteries like occipital vein.
How come infection of scalp can spread to cranial cavity and meninges?
Valveless emissary veins connect veins of the scalp to diploic veins of the skull and this duralumin venous sinuses.
How can infection of facial vein spread to Dural venous sinuses?
Facial vein is valveless and connected to ophthalmic vein draining into cavernous sinus. Moreover deep fasciae veins drain into pyterigoid venous plexus.
Issue in thrombophlebitis of fasciae vein.
Where does the jugular vein leave and name 5 sinus’
Jugular foramina
Sigmoid sinus (IJV continuation) Transverse Cavernous Inf sagittal Sup sagittal
