Blood Vessels of Head and Neck Flashcards
What type of blood do arteries carry?
Oxygenated
Arteries have a smaller diameter than veins. True or false?
True
Why do arteries have a paler colour?
Because it has a thicker wall. The dark colour of veins is due to contained blood being partly visible through thin walls.
How does blood flow in the arteries?
Under pressure from the heart
In which cases do arteries have valves?
Origins of aorta and pulmonary artery
Arteries are usually accompanied by veins. True or false?
True
Why are veins usually more superficial?
So that slow venous return is not compressed by overlying artery.
What are the two types of nerves associated with arteries?
- Muscle contraction (vasomotor)
2. Hitchhikers
What are the characteristics of vasomotor nerves?
- Penetrate wall
2. Sympathetic (accompanied by sensory fibres)
What are the characteristics of hitchhikers?
- Remain outside adventitia
2. Can be parasympathetic, sympathetic, sensory or a combination
How do lymph plexuses arise? Where do they sit?
Small lymph vessels form a plexus on the walls of many large arteries.
What is an arterial anastomosis?
Connection between 2 arteries rather than the usual pattern of arteries of decreasing size emptying into a network of capillaries and from there into a network of veins of increasing size.
What does an arterial anastomosis mean they can do?
They can influence/feed into each others territories
What are the 3 types of arterial anastomoses?
1) One artery opening directly into another (e.g. L and R superior labial arteries)
2) Two arteries coming together to form a single artery (e.g. vertebral arteries forming the basilar artery inside the skull)
3) Two arteries linked by a small connecting artery
What is the endothelium?
A single layer of flattened epithelial cells that forms the innermost lining of all vessels - blood and lymph
At what level is the arch of aorta?
Manubriosternal joint
Where does the brachiocephalic trunk, left common carotid and left subclavian artery rise from?
Rise from arch of aorta behind manubrium.
Where does the brachiocephalic trunk divide?
Divides at the level of the right sternoclavicular joint
What does the braciocephalic trunk divide into?
Right common carotid and subclavian
At what level does the common carotid divide?
At the top of the thyroid cartilage of larynx.
What does the common carotid divide into?
Internal and external carotids
Where are the carotids located?
On either side of trachea, thyroid gland, larynx, pharynx and deep to sternocleidomastoid
What does the carotid sheath enclose? (3)
- Common and internal carotids (medial)
- internal jugular (lateral)
- Vagus (posterior)
What is the ansa cervicalis? What does it supply?
- A nerve loop arising from cervical spinal nerves
2. Supplies muscles of the anterolateral neck.
Where is the ansa cervicalis located?
Anterior to the carotid sheath.
Where does the sympathetic trunk lie in relation to the carotid sheath?
Posterior
What is the carotid sheath made of?
Thin sheet of dense fascia enclosed in looser adjacent fascia.
What does the superior thyroid artery pass? Where is it located?
- Passes inferiorly to THYROID GLAND
2. Deep to infrahyoid strap muscles of neck (flat muscles superficial to larynx and thyroid gland)
What does the superior thyroid artery supply?
Thyroid
What else is the thyroid supplied by?
Pair of inferior thyroid arteries from thyrocervical trunk (branch of the subclavian artery)
Where does the lingual artery pass?
- Passes deep to intermediate tendon of digastric and submandibular gland.
- To side of tongue.
Where does the facial artery run? (2) What type of course does it have?
- Loops posterior to submandibular gland
- Passes over body of mandible
Wavy course and superficial
What are the branches of the facial artery?
1) Tonsilar artery
2) Submental artery
3) Inferior and superior labial arteries
What does the facial artery supply? (5)
- Soft palate
- Tonsils
- Submandibular and sublingual glands
- Adjacent muscles
- Superficial face
What are the possible variations for the facial artery?
- Lingual and facial arteries often arise as a common trunk
2. They arise as a common trunk with the superior thyroid artery
Where does the ascending pharyngeal artery arise?
It is a small posteior branch arising near the origin of the external carotid.
Where does the ascending pharyngeal artery pass?
- Arises well below posterior belly of digastric and close to origin of external carotid.
- It passes deep to the styloid muscles
What does the extracranial branch of the ascending pharyngeal artery supply?
Supplies outside cranium (extra cranial):
- Upper pharynx
- TMJ
- Tymapnic cavity
- Meninges
Where does the intracranial branch pass and what does it supply?
It passes through the foramen magnum and supplies the meninges.
Where does the occipital artery run?
It runs deep to the posterior belly of the digastric muscles and it passes behind the mastoid
What does the occipital artery supply? Where does it sit?
- SCM
- Muscles and skin of occiput
It sits medial to the mastoid groove.
Where does the posterior auricular artery arise? What does it supply?
It is a posterior branch which arises above the posterior belly of digastric
It supplies part of the parotid, auricle and occipital region.
Where does the occipital artery arise in relation to the posterior belly of the digastric muscle? What does it have a branch to? Where does that run?
Passes deep to posterior belly and usually has a branch to the SCM (stump) and passes posterior to the external ear and across occiput.
Where does the posterior auricular artery arise in relation to the posterior belly of the digastric muscle?
Above level of posterior belly of digastric.
What are the two terminal branches of the external carotid?
It divides in the parotid to form:
- Superficial temporal artery
- Maxillary artery
What other structures passes through the parotid?
- Retromandibular vein
2. Facial nerve
What are the important branches of the superficial temporal artery?
- Transverse facial artery
2. Zygomatico-orbital artery
Where does the transverse facial artery arise? What does it supply?
It arises from the superficial temporal artery within the parotid below the zygomatic arch.
It passes anteriorly to supply part of the parotid and inferior part of the orbicularis oculi.
Where does the zygomatico-orbital artery arise and what does it supply?
It arises just above the zygomatic arch and supplies the superior orbicularis oculi.