3.1 workbook: extra-cranial blood vessels: arteries Flashcards
is the L or R common carotid artery longer?
left by 2cm in the superior mediastinum before entering the neck
what encloses each common carotid artery as it ascends up through the neck?
enclosed within the carotid sheath
what is the carotid sheath? function?
a fascial envelope enclosing as well as separating the carotid artery, internal jugular vein and vagus nerve from each other
where is the carotid sheath found?
deep to the SCM muscle
what is the carotid sheath derived from?
fusion of:
- prevertebral layer of cervical fascia (posteriorly)
- pretracheal layer (anteromedially)
- investing layer of cervical fascia (anterolaterally)
how thick is the carotid sheath?
thin over the internal jugular vein, but thicker around the carotid artery
where does the carotid artery lie within the carotid sheath?
medially within the sheath
where does the internal jugular vein lie within the carotid sheath?
lateral
where does the vagus nerve lie within the carotid sheath?
behind and in between the artery and vein
where does the sympathetic trunk lie in relation to the carotid sheath?
medially and behind it
where do the common carotids terminate?
at the level of the upper border of the thyroid cartilage
what happens as the common carotids terminate at the upper border of the thyroid cartilage?
it divides into internal and external carotid arteries
what is significant at the division (bifurcation) of the common carotids?
the internal carotid artery is more bulbous due to the carotid sinus (carotid body)
what does rubbing the carotid sinus cause?
alleviate supra-ventricular tachycardias (SVT)
carotid massage - treat patients presenting with supraventricular tachycardia
which structure runs across the posterior triangle?
spinal part of the accessory nerve
what can massage the carotid artery cause?
severe bradycardia and a significant drop in blood pressure
when palpating the carotid artery, what should you ensure?
palpate them ONE at a time - do NOT palpate both
what is the internal carotid artery distinguished by? why?
a lack of branches in the neck as it ascends to supply INTRA-cranial structures
what does the external carotid artery supply?
major source of blood supply to extra-cranial structures of head + neck region
how many branches does the external carotid artery give rise to?
8 branches
what are the terminal branches of the external carotid artery?
maxillary and superficial temporal arteries
where does the external carotid artery divide into its terminal branches?
at a level behind the neck of the mandible, within the substance of the parotid gland
where does the arterial supply to the head and neck arise from?
branches of the R + L common carotid arteries and vertebral arteries
what are the vertebral arteries branches of?
subclavian arteries
what do the vertebral arteries supply?
posterior neck and posterior parts of the brain
where does the vertebral artery ascend through from its origin?
through the transverse foramina of the cervical vertebrae (except C7) and enters the subarachnoid space
where is the subarachnoid space?
between the atlas and occipital bone
where does the vertebral artery ascend after it enters the subarachnoid space? then forms?
passes through the foramen magnum, curving around the medulla, to join the vertebral artery from the other side to form the basilar artery
where does the basilar artery travel?
runs along anterior aspect of the brainstem
