Blood Vessels Head And Orbit Flashcards
(16 cards)
What is the main aim of studying the blood supply to the head and orbit?
To understand the main arteries branching off the aorta and their supply to the head and brain
Key areas include the carotid arteries, vertebral arteries, circle of Willis, and vascular territories related to ischaemic strokes.
At which vertebral level do the carotid arteries bifurcate?
C4
This is at the upper border of the thyroid cartilage.
What is the carotid sinus?
A dilation of the internal and common carotid arteries at the bifurcation point
It plays a role in regulating blood pressure.
What areas do the external carotid arteries supply?
Areas of the head and neck external to the cranium
This includes various branches that provide blood to the facial and neck regions.
List the branches of the external carotid artery.
- Superior thyroid artery
- Ascending pharyngeal artery
- Lingual artery
- Facial artery
- Occipital artery
- Posterior auricular artery
- Maxillary artery
- Superficial temporal artery
Where do the internal carotid arteries enter the cranial cavity?
Via the carotid canal in the petrous part of the temporal bone
They do not supply structures in the neck.
What do the internal carotid arteries supply within the cranial cavity?
- The brain
- Eyes
- Forehead
What is the origin of the vertebral arteries?
They arise from the subclavian arteries
Paired vessels that ascend posterior to the carotids.
What do the vertebral arteries form after entering the cranium?
The basilar artery
This artery supplies the brain.
What is the Circle of Willis?
A circular anastomosis that supplies blood to the brain and surrounding structures
It consists of 3 cerebral arteries and 2 communicating arteries.
What does the Bamford classification describe?
It describes 4 main types of ischaemic stroke
The types are TACS, PACS, LACS, and POCS.
What is the first branch of the internal carotid artery?
The ophthalmic artery
It enters the orbit via the optic canal.
List the branches of the ophthalmic artery.
- Central retinal artery
- Ciliary arteries
- Lacrimal artery
- Muscular branches
- Supraorbital artery
- Posterior ethmoidal artery
- Anterior ethmoidal artery
- Meningeal artery
- Medial palpebral artery
- Supratrochlear artery
- Dorsal nasal artery
What is the blood-retinal barrier?
Formed by zona occludens of RPE and CRA endothelium
It protects the retina by regulating the passage of substances.
What is CRAO?
Central retinal artery occlusion
It affects the inner 2/3rds of the retina and is caused by the central retinal artery being an end artery.
What do the ciliary arteries supply?
The outer 1/3rd of the retina
They anastomose within the choroid.
