Blood Supply to the Head & Orbit Flashcards
What is the ascending aorta?
The ascending aorta arises from the aortic orifice from the left ventricle and ascends to become the aortic arch. It is 2 inches long in length and travels with the pulmonary trunk in the pericardial sheath.
What does the right common carotid feed into?
Head & Neck
What does the right subclavian artery feed into?
Right upper limb
What does the left common carotid artery supply?
Left side of the head and neck
What does the left subclavian artery supply?
Left upper limb
Sometimes doesn’t have a name as it has multiple branches on it such as the left axillary artery and left brachial artery.
What is the thoracic aorta?
The thoracic (descending) aorta spans from the level of T4 to T12. Continuing from the aortic arch, it initially begins to the left of the vertebral column but approaches the midline as it descends. It leaves the thorax via theaortic hiatus in the diaphragm, and becomes the abdominal aorta
Where do the carotid arteries extend?
Up the neck lateral to the oesophagus and trachea
Where do the carotid arteries split?
2 become 4 at C4. Internal deeper and closer to the midline, external common carotid is on the outside.
What do the carotid arteries border?
Superior border is jawline/mandible, lateral border is the SCM, medially is midline of neck so carotid triangle and the Anterior triangle are the same
Where are baroreceptors?
Baroreceptors are in this area (carotid bodies) and if massaged it can help slow heart rate down by stimulating the baroreceptors by pressing on the common carotid
What is it called where arteries meet and balloon?
Sinus
What is the carotid triangle the same as?
The anterior triangle of the neck
Superiorly– inferior border of the mandible (jawbone).
Laterally– anterior border of the sternocleidomastoid.
Medially– sagittal line down the midline of the neck.
What is the carotid sinus?
Where the internal carotid and common carotid are dilated. This is where baroreceptors are.
What does the external carotid artery supply?
Most lateral, supplies areas of the head and neck external to the cranium
What is the mnemonic to remember the external carotid arteries?
Some
Anatomy
Lecturers
Freak
Out
Poor
Medical
Students
What are the branches of the External Carotid Arteries?
Some -
Superior Thyroid Artery
Anatomists -
Ascending Pharyngeal Artery
Like -
Lingual Artery
Freaking -
Facial Artery
Out -
Occipital Artery
Poor -
Posterior Auricular Artery
Medical -
Maxillary Artery (largest)
Students -
Superficial Temporal Artery
What are the two terminal branches (end arteries) of the external carotid arteries?
Maxillary Artery & Superficial Temporal Artery
What does the Maxillary artery supply?
Mandibular (1st part)
Pterygoid (2nd part)
Pterygopalatine (3rd part)
What does the superficial temporal artery supply?
It’s a branch of the external carotid arteries that supplies superficial structures of the face
What do the internal carotid arteries supply?
Entering the cranial cavity via the carotid canal in the petrous part of the temporal bone. Within the cranial cavity, the internal carotid artery supplies:
- The brain
- Eyes (ipsilateral)
- Forehead
Where are the internal carotid arteries in the neck?
Deeper in the neck
What are the vertebral arteries?
Paired vessels arising from the subclavian arteries.
Thinner than the carotid arteries = more fragile. They run up the neck on the side of the vertebra in a ring to make them more protected as encased in a bit of bone from the cervical vertebra.
Where do the vertebral arteries ascend?
Posterior (behind) the carotids, encased in transverse processes of the cervical vertebrae
Travel up and enter the cranium through the foramen magnum
Where do the vertebral arteries meet? What do they form?
Meet at the base of the brainstem to form the basilar artery. This sits on the pons.
What is the Circle of Willis?
A circular anastomoses that supplies blood to the brain and surrounding structures.
Small variations can exist however the general composition is 3 cerebral arteries and 2 communicating arteries
Bunch of blood vessels that meet together in a ring, called an anastomoses
Why does the Circle of Willis exist?
The arrangement of the brain’s arteries into the circle of Willis is believed to create redundancy (analogous toengineered redundancy) for collateral circulationin thecerebral circulation. If one part of the circle becomes blocked or narrowed (stenosed) or one of the arteries supplying the circle is blocked or narrowed, blood flow from the otherblood vessels can often preserve the cerebral perfusion well enough to avoid the symptoms ofischemia
Where is the Circle of Willis?
Tucked in against the brainstem with the lobes surrounding it
What structures are included in the Circle of Willis?
Anterior spinal arteries =
Dive back to feed the anterior part of the spine
Anterior inferior cerebellar artery = Front, lower part of the cerebellum
Pontine arteries =
Arteries that feed the pons – cranial nerves come from here and the pontine respiratory group etc
Superior cerebellar arteries =
Goes to top of cerebellum
Posterior Cerebral =
Goes to back of the cerebrum
Posterior communicating arteries = Link lower arteries into the circle
Middle cerebral artery =
Commonly affected in strokes, contralateral blood supply
Ophthalmic artery =
Part of the eyes
Anterior communicating artery = Link left and right together
What’s included in the ACA (Anterior Cerebral Artery)?
- Medial frontal lobe
- Superomedial parietal lobe
- Internal capsule (carries both ascending and descending pathways to and from the cerebral cortex from the brainstem
Where does the Middle Cerebral Artery supply?
The most of lateral surface of hemisphere i.e temporal lobe, part of parietal and frontal lobes
What does the Posterior Cerebral Artery supply?
- Midbrain and thalamus
– Occipital lobe and visual cortex - Inferomedial temporal lobe
- Brainstem
What is total circulation stroke (TACS)?
Anterior cerebral artery
How is TACS diagnosed?
Total Anterior Circulation Stroke (TACS)
Anterior and Middle Cerebral Arteries
All 3;
- unilateral weakness or sensory deficit of the face, arm and leg
- Homonymous Hemianopia
- Higher cerebral dysfunction (dysphasia, visuospatial disorder)
How is Partial Anterior Circulation Stroke (PACS) diagnosed?
2 of these 3;
- unilateral weakness or sensory deficit of the face, arm and leg
- Homonymous Hemianopia
- Higher cerebral dysfunction (dysphasia, visuospatial disorder)