Lecture 3- Internal branch of the carotid artery Flashcards
the head and neck recieves most its blood supply through the
carotid and vertebral arteries
anatomy of of the carotid arteries. arise from the arch of the aorta
the right common carotid arery arises from
a bifurication of the brachiocephalic trunk (right subclavian is the other branch)
- occurs roughly at the level of the right sternoclavicular joint
the left common carotid branches
directly from the arch of the aorta
the left and right common carotid arteries ascend up the neck…… to the trachea and the oesophagus
lateral
when does the carotid arterie bifuracte into the external and interal carotid arteries
superior margin of the thyroid cartilage (C4)
bifurcation occurs in an anatomical area known as the carotid triangle.
features of the common carotid and itnenra carotid at the carotid triangle
slightly dilated here, this area is known as the carotid sinus, and is important in detecting and regulating blood pressure
what is also found in the carotid sinus
baroreceptors for HR
the glossopharyngeal nerve feeds this information to the brain, and this is used to regulate blood pressure.
Importance of carotid triangle
- Bifurcation of the common carotid occurs here
- Important clinically
- Surgery
- Atherosclerosis
- Carotid sinus massage
- Central pulse
- Access site for vagus and hypoglossal nerves
- Contains internal jugular vein (access site for central line placement)
Carotid triangle borders
- Superior border- posterior belly of the digastric muscle
- Medial/inferior border- superior belly of omohyoid muscle
- Lateral border- medial border of SCM
the carotid sinus is a common site of
Atherosclerosis
- Bifurcation is a common site of atherosclerosis
- Causes artery to narrow (stenose)
- Plaque rupture can release an embolus which can travel to brain
- Stroke or TIA depending on size
- Transient loss of vision (amaurosis)
procedure on carotid sinus with atherosclerosis
Carotid endarterectomy - to reduce risk of stroke
- Incision in neck and the carotid to remove plaque tissue and stich back up
- Important to know carotid triangle boundaries
Carotid sinus massage
- Pressure at the site of carotid bodies
- Increased baroreceptor activity feedback to the heart to slow down
- Important area to feel in clinical examination to determine pulse
interanal carotid arteries do not supply
any sturctures in the neck- no branching in the neck
where does the intenral carotid artery enter the cranial cavity
via the carotid canal in the petrous part of the temporal bone
the internal carotid artery supplies:
The brain
Eyes
Forehead
Vertebral arteries arise from
left and right subclavian arteries
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how do the vertebral artery ascend up the neck into the skull
- Ascend up the cervical vertebrae through the transverse foramina
- Entering the base of the skull via the foramen magnum
internal carotid arteires and vertebral arteries supply the
brain with blood
where is the carotid canal found
within the petroud part of the temporal bone
allows intenral carotid to pass through the base and enter the skull
how does the internal carotid artery enter the brain via the carotid canal
- Turns medially and horizontally
- Enters the cranium and makes an s-shaped bend
- Moves through cavernous sinus
Cavernous sinu
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- Venous type structure on the upper surface of the sphenoid bone
- Vessels that flow through the carotid sinus:
- Carotid artery
- CN III (Oculomotor)
- CN IV (Trochlear)
- CN VI (Abducens)
- 2 branches of CN V (Trigeminal) ( CN V1 ophthalmic and CN V2 maxillary)
first branch of the internal carotid artery
opthalmic artery (which follows the opthalmic nerve)
branches of the opthalmic artery
- central rentianl artery (if you lose blood supply to the ophthalmic artery the retina will die and lose sight)
- supra-orbital artery
- surpatrochlear artery
the circle of willis
other branches of the itnernal carotid
Other branches provide arterial blood to the brain
◦ Anterior cerebral artery
◦ Middle cerebral artery
◦ Posterior communicating artery
