Orbital Vasculature Part I Flashcards
What kind of BV carry oxygenated blood away from the heart
Arteries
What blood vessels are under higher pressure?
Arteries
What are the layers of the arteries
- external tunic (adventitia)
- tunica media
- tunica intima
- internal elastic lamina
- external elastic lamina
External tunic (adventitia) of arteries
Collage fibers/connective tissue
Tunica media of arteries
Composed of smooth muscle and elastic tissue
Tunica intima of arteries
Composed of endothelial cells (direct contact with lumen)
Internal elastic lamina of arteries
Outer most portion of the tunica intima
External elastic lamina of arteries
Inner most portion of the tunica adventitia
Where do arteries drain to
Arterioles
Primary site of vascular resistance
Arterioles
Where do arterioles drain to
Capillaries
What is the tunica media of arterioles like compared to the arteries
Thinner
Endothelial cells and their basement membrane
Capillaries
What lines the external surface of the capillaries?
Pericytes
What is the function of the capillaries
exchange of nutrients and metabolic waste
What are venules lined with
Endothelial lining Tunica media (thin) Tunica adventitia
Where do venules drain to
Veins
Carry deoxygenated blood to heart
Veins
Tunica of veins
Same as arteries, but tunica media is much thinner and the tunica adventitia is much thicker. They lack elastic lamina
What does the brachiocephalic artery give rise to
The right subclavian and tight common carotid artery
Where do the left common carotid artery and the left subclavian artery branch from?
Directly from the Arch of the aorta
When does the common carotid artery bifurcate and what does it bifurcate into?
After it enters the carotid sheath, it bifurcate into the internal and external carotid artery
As the internal carotid artery ascends into the neck inside the carotid sheath, what does it carry with it?
A plexus of postganglionic sympathetic nerve fibers
Does the internal carotid artery have any branches outside of the skull?
No
How does the internal carotid artery enter the skull
Through the carotid canal
Where does the internal carotid artery emerge from and into what fossa?
Emerges from the petrous portion of the temporal bone and into the middle cranial fossa
How does the internal carotid course?
Anterior over the foramen lacerum
What sinus does the internal carotid artery enter after it courses over the foramen lacerum?
Cavernous sinus
The ________ nerve sits inferolateral to the internal carotid artery within the cavernous sinus
Abducens (CN VI)
What cranial nerves sit lateral to the internal carotid artery and course in the lateral wall of the cavernous sinus?
- oculomotor nerve (CNIII)
- trochlear nerve (CNIV)
- ophthalmic and maxillary divisions of the trigeminal nerve (CNV)
Where does the carotid artery exit the roof of the cavernous sinus?
Just medial to the anterior clinic process
As the internal carotid artery dips inferior to the optic nerve, what happens?
It gives off the ophthalmic artery at the posterior opening of the optic canal
Where does the ophthalmic artery enter the optic canal?
Inferior and lateral to optic nerve
How does the ophthalmic artery course in the dural sheath of optic nerve?
Anterior, and then pierces dural sheath and lies just lateral to the optic nerve in the orbit
Once the ophthalmic artery pireces the dural sheath of the optic nerve, what does it do?
Courses anterior for a shirt distance stalling lateral to the optic nerve, then makes an abrupt medial turn over the optic nerve and is joined by the nasociliary nerve
As the ophthalmic artery joins the nasociliary nerve, how does it run?
Courses anterior along the medial wall of orbit between the superior oblique muscle and medial rectus muscle
How does the ophthalmic artery terminate
As the supratrochlear and dorsonasal arteries
How many arteries branch from the ophthalmic artery?
Eleven branches to supply eye, orbit, and extra orbital structures
Ocular (2)
Orbital (2)
Extraorbital (7) and one sorta
What are all the branches of the ophthalmic artery?
- central retinal artery
- ciliary arteries
- Lacrimal artery
- muscular arteries
- supraorbital artery
- posterior ethmoidal artery
- anterior ethmoidal artery
- recurrent meningeal artery
- medial palpebral arteries
- supratrochlear artery
- dorsonasal artery
What are the ocular branches of the ophthalmic artery
- central retinal artery
- ciliary arteries
What are the orbital branches of the ophthalmic artery?
- lacrimal artery
- muscular arteries
What are the extra orbital branches of the ophthalmic artery?
- supraorbital
- posterior ethmoidal
- anterior ethmoidal
- recurrent meningeal
- medial palpebral
- supratrochlear
- dorsonasal
What is the first and smallest branch of hte ophthalmic artery?
Central retinal artery
Where does the central retinal artery branch off of the ophthalmic artery?
Near optic canal and inferior to optic nerve
How does the central retinal artery course after it comes off of the ophthalmic artery?
Anterior and pierces the dural sheath of optic nerve 5-15mm from posterior scleral aperture
After the central retinal artery pierces the dural sheath of the optic nerve, what does it do?
Obliquely crosses subarachnoid space to enter substance of the nerve and course with the central retinal vein to the lamina cribrosa and enters back of the eye
What supplies the pill meninges surrounding the optic nerve?
Small pial branches from the central retinal artery
Where does the central retinal artery emerge inside the ey
On nasal side of optic disc just nasal to the central retinal vein
Once the central retinal artery enters the eye, how does it branch?
Divides into superior and inferior branches, which bifurcate into temporal and nasal branches
What does each branch of the central retinal artery do once it is in the eye?
Provides arterial blood to the inner retinal layers in each respective quadrant
Where does the ciliary artery branch from the ophthalmic artery?
As it courses over optic nerve, they arise as medial and lateral trunks that give rise to short and long posterior ciliary arteries
Long posterior ciliary arteries
- medial and lateral
- pierce sclera medial and lateral to arterial circle of Zinn-Haller
- travel anterior inside the eye via suprachoroid (perichoroid) space