Session 3 Flashcards
(40 cards)
Where do vertebral arteries branch from and what do they supply?
Subclavian arteries. Supply posterior neck and posterior parts of the brain
Describe the route of the vertebral arteries in the neck
Travels through the intervertebral foramen then passes through the foramen magnum and they join together to become the basilar artery.
What is the carotid sheath derived from?
Contributions from the pretracheal, prevertebral and investing layer of cervical fascia.
Where do the internal jugular vein and carotid artery lie in relation to each other?
Vein is lateral in the sheath
What is the site of the carotid sinus and why is this clinically relevant?
Bifurcation of the common carotids - at the level of the upper border of the thyroid cartilage. Rubbing this area can alleviate supra ventricular tachycardias.
How many branches does the internal carotid artery have in the neck?
0
What are the branches of the thyrocervical artery? (which originates from the aorta)
Ascending and transverse cervical arteries (supply neck), inferior thyroid artery (lower thyroid) and suprascapular artery (shoulder).
Where does the internal carotid artery enter the skull?
Through the carotid canal in the temporal bone
What is the difference between the carotid sinus and the carotid body?
Sinus - a swelling that is the location of baroreceptors
Body - peripheral chemoreceptor
What are the boundaries of the carotid triangle?
Superior - posterior belly of digastric
Lateral - sternocleidomastoid
Medial - superior belly of omohyoid
What are the contents of the carotid triangle and what is its clinical relevance?
Internal jugular vein and bifurcation of common carotid artery. Carotid massage, pulse, surgical access, vagus nerve access
Describe the broad blood supply to the scalp
Many anastomoses, mainly branches from external carotid artery but two arteries are branches of the opthalmic artery (from internal carotid via orbit)
Why does the loss of scalp not usually lead to skull necrosis?
Skull mostly supplied by the middle meningeal artery (from maxillary artery)
Why do deep lacerations involving the epicranial aponeurosis cause profuse bleeding?
There are numerous anastomoses, limited constriction due to the walls of arteries being attached to connective tissue and there is opposing pull of occipitofrontalis
What vein drains most of the blood from the face and where does it run?
Facial vein. From medial angle of the eye down to the inferior border of the mandible. Drains into internal jugular vein.
How can infections of the scalp spread to the cranial cavity?
Through valveless emissary veins that connect veins of scalp to diploic veins of skull.
How is the bone and scalp flap reflected during a craniotomy?
Inferiorly to preserve the blood supply.
Where can the facial artery pulse be felt?
Inferior border of mandible anterior to masseter
What are dural venous sinuses?
Endothelial lined spaces between periosteal and meningeal layers of dura at dural septae. Receive blood from large veins.
What happens to the sigmoid sinuses?
They continue as the internal jugular veins, leaving the skull at the jugular formaina
What is the cavernous sinus?
Plexus of thin walled veins on upper surface of sphenoid. One either side of sella turcica. Space created by splitting of dural layers.
Describe the connection of facial veins with the cavernous sinus and the pterygoid venous plexus and clinical relevance
(Facial veins are valveless)
Cavernous sinus - facial vein via superior opthalmic vein at medial angle of eye
Pterygoid venous plexus - from deep facial veins. Infections and septic thrombi can spread.
Where are the constituents of lymph?
Tissue fluid, small proteins, chylomicrons from gut lymphatics, damaged cells, bacteria, cancer cells
How much lymph does the body produce per day?
3-4L
