37 terms

Extra/Intra Cranial anatomy

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What are the five sections of the aorta?
Root
Ascending
Descending
Abdominal and branches
Bifurcation into iliacs
What are the three branches off of the aortic arch?
Innominate (brachiocephalic)
Lt CCA
Lt subclavian a.
What does the innominate artery branch to form?
Rt Common Carotid Artery
Rt subclavian artery
What are the two main branches of the subclavian artery?
Vertebral a.
Thyrocervical a.
What is the first branch of the subclavian artery?
Vertebral
What do the right and left vertebral arteries anastomose to form?
The basilar artery
Which side typically has a smaller vertebral artery?
Right.
Where does the CCA bifurcate?
At the level of the thyroid cartilage.
Which is typically larger, the ECA or ICA?
ICA.
What structures do the ICAs feed?
Anterior brain, eyes, forehead and nose.
How are the ECA and ICA typically positioned in relation to each other?
In 95% of cases, the ICA is posterior to the ECA
What is the first branch of the ICA?
The opthalmic artery.
What does the opthalmic artery originate near?
The carotid siphon.
What does the opthalmic artery branch into?
Supraorbital
Lacrimal
Frontal
Nasal
What are the branches of the ICA?
Opthalmic a.
Anterior choroidal a.
Posterior communicating a.
What are the 8 branches of the ECA?
Superior thyroid
Ascending pharyngeal
Lingual
Occipital
Facial
Posterior auricular
Maxillary
Superficial temporal
What are the 4 segments of the intercranial ICA?
From inferior to superior:
Cervical
Petrous
Cavernous
What are the boundaries of the cervical portion if the ICA?
From the bifurcation of the CCA to the carotid canal of the temporal bone.
Where does the petrous portion of the ICA course?
Through the petrous portion of the temporal bone, making it inaccessible to ultrasound.
What is the cavernous portion of the ICA also known as?
The carotid siphon.
What does the cavernous portion of the ICA consist of?
The parasellar and genu portions.
What comprises the distal portion of the cavernous segment of the ICA?
The supraclinoid.
What portion of the ICA does the opthalmic artery arise from?
The genu of the cavernous portion of the ICA.
In what direction do the Middle Cerebral Arteries (MCAs) course?
Laterally towards the temporal bones.
What percent of ICA flow is carried by the MCAs?
75-80%
What are the two segments of the MCA?
M1 - from the origin to the first branch
M2 - Distal from the first branch
What does the terminus of the ICA bifurcate into?
Middle Cerebral Artery
Anterior Cerebral Artery
What do the ACAs course towards?
Medially towards the midbrain.
What connects the two ACAs?
The anterior communicating artery.
What are the two segments of the ACA?
A1 - from the ICA to the ant. comm. artery
A2 - distal to the anterior comm. artery
Where do the vertebral arteries course?
Between the transverse processes of the spine.
Where do the vertebral arteries enter the skull?
At the foramen magnum.
What are the intracranial branches of the vertebral artery?
Anterior spinal artery
Posterior inferior cerebellar artery
Approximately how long is the basilar artery?
3 cm
What does the basilar artery bifurcate into?
The posterior cerebral arteries.
What do the PCAs feed?
The posterior hemispheres and they wrap around the peduncles.
What are the two segments of the PCAs?
P1 - origin to the post. comm. artery
P2 - distal to the post. comm. artery