Major Blood Vessels of the Head and Neck Flashcards
What muscle covers blood vessels? What is the exception?
The SCM covers most blood vessels, apart from external jugular vein
Describe the location of the EJV vs IJV in relation to the SCM?
External jugular vein runs along the outside of the SCM, can be seen
Internal Jugular vein is located underneath the SCM, not visible
Describe the relation of the CCA and Vagus Nerve to the IJV
CCA is medial to the Internal Jugular vein
Vagus nerve runs behind it
Label the image below
Where does most of the blood supply to the head and neck come from?
How does this artery divide and what speciifc structures do these supply?
Most of blood supply comes from carotid artery
Divides into
- Internal carotid – brain (with vertebral artery)
- External carotid – face, scalp, skull
What is the blood supply to the scalp?
The ECA and 2 small branches of ICA - supratrochlear and supraorbital
What artery supplies the face?
What is this a branch of?
Facial artery - branch of the ECA
What veins drain into the cavernous sinus and pterygoid plexus?
What is the clinical importance?
Some deep facial and scalp veins - potential route of infection
What 3 branches does the Subclavian artery gives off in the neck?
1) Vertebral a.
2) Thyrocervical a.
3) Internal Thoracic a
What do the vertebral arteries arise from?
Through what structure do they ascend through neck?
Arise of the subclavian arteries on L and R
Ascend in the neck through transverse foramina in cervical vertebrae 6-5-4-3-2-1
What 2 arteries supply the brain?
The Vertebral arteries and Internal carotid arteries
Through what structure does the ICA enter the skull?
Enters skull through carotid canal
What are the 4 major branches of the Thyrocervical Trunk?
1) Suprascapular a.
2) Transverse Cervical
3) Inferior Thyroid
4) Ascending Cervical
What artery supplies the Thyroid?
What does this arise from?
Inferior Thyroid a.
Arises from the Thyrocervical Trunk
At what anatomical location does the CCA bifurcate?
Around the level of the superior border of the thyroid cartilage
What 2 arteries have NO branches in the neck?
The CCA and the ICA
What are the boarders of the carotid triangle?
Superior: digastric (posterior belly) and stylohyoid
Lateral: medial border of SCM
Inferior: superior belly of omohyoid muscle
What are the contents of the carotid triangle?
IJV and bifurcation of CCA
What vein, artery and nerves can be accessed in the carotid triangle?
IJV, CCA, Vagus n. and Hypoglossal n.
Where can the carotid pulse be felt?
In carotid triangle (may also be palpated more inferiorly)
What can be done to a patient with SVT and why?
Carotid sinus massage.
Massaging this area stimulates CN IX (glossopharyngeal n.)
This goes to brain and stimulatess Vagus nerve (CN X) to slow down HR
Where is the carotid sinus located?
What important structures are found here?
Swelling located on the ICA at the region of bifurcation
Location of baroreceptors for detecting changes in arterial BP
Where is the carotid body located?
What important structures are found here?
Located at the bifurcation
Peripheral chemoreceptors which detect arterial O2
Bifurcation of the carotid artery is a common site for what?
Describe what this can lead to
Atheroma formation
Plaque causes narrowing (stenosis) of the artery
Rupture of the fatty deposit can cause an embolus to travel to brain resulting in a TIA or stroke
How many carotid sheaths do we have?
What forms the sheaths?
What is contained in each?
2 carotid sheaths, formed by contributions from investing, prevertebral, and pretracheal layers
Each contains: CCA, ICA, IJV, Vagus n. (ECA leaves sheath at bifurcation)
How could we differentiate the CCA from the IJV? (3)
Artery: thick and rounded walls
Vein: thin, more distended walls
Artery is also MEDIAL to the vein
Label the 6 branches + 2 terminal branches of the ECA?
What does each supply?
- Superior thyroid ➞ thyroid
- Lingual ➞ tongue
- Facial ➞ face
- Ascending pharyngeal ➞ pharynx
- Occipital ➞ eyes
- Posterior auricular ➞ ear
- Superficial temporal ➞ temporal area of skull
- Maxillary artery ➞ through parotid gland to maxilla, teeth and nose
What are the 2 terminal branches of the ECA?
1) superficial temporal ➞ goes to temporal area of skull
2) maxillary artery ➞ through parotid gland to supply the maxilla, teeth and nose
Label the image below and explain why
A: External carotid (because it has many branches)
B: Internal carotid (because has no branches)
C: Common carotid (because it has no branches and then bifurcates into two main branches)
Arteries that supply the face arise from where?
Majority is from arteries arising from the Facial artery (from the ECA)
EXCEPT
Supraorbital and Supratrochlear which are from ICA (via ophthalmic a.)
Where can the Facial artery pulse be felt?
Facial artery pulse can be felt at inferior border of mandible, anterior to the masseter muscle
The Angular artery is a continuation of what artery?
Facial artery
What are the 5 Major Branches that supply blood to the scalp?
State which comr from the ECA vs ICA
1) Occipital (ECA)
2) Superficial Temporal (ECA)
3 Posterior Auricular (ECA)
4) Supratrochlear (ICA)
5) Supraorbital (ICA)
Label the image of the SCALP
What is the blue located at the centre?
Blue: dural venous sinus
What is the Blood Supply of the Scalp?
Rich blood supply with many anastomoses
Largely branches of ECA
EXCEPT Supratrochlear and supraorbital a. (arise from the ICA)
How are arteries of the scalp help open?
Walls of arteries closely attached to connective tissue, limits constriction (holds arteries open)
What would the result of a deep laceration involving epicranial aponeurosis be?
Cause profuse bleeding because of opposing pull of occipitofrontalis muscle
What provides blood supply to the skull?
What can be said about injury to scalp vs skull?
Middle Meningeal Artery
Supply of skull is different from scalp, hence loss of scalp does not lead to bone necrosis whereas loss of skull supply would
Describe the superficial venous drainage of the head and neck?
1) EJV ➞ Subclavian v. (crosses SCM as it descends neck)
2) Anterior Jugular v.
Describe the deep venous drainage of the head and neck?
Internal Jugular v. (inside the carotid sheath, DEEP to SCM)
⬇
Collects blood from skull, brain, superficial face, and neck
⬇
Joins the subclavian veins posterior to the sternal end of the clavicle to form the brachiocephalic veins
** Has multiple tributaries
Is the EJV or IJV easier to see and why?
EJV vein much easier to see because IJV is underneath SCM
Which vein should be used to most accuratly indicate RA pressure? How?
Right IJV → look for pulsations of vein under SCM
How do we measure JVP?
IJV is largely hidden by SCM so the pulsations are observed through muscle
Use RIGHT IJV because it is effectively a direct connection to the RA
Observe with patient at 45 degree angle with Height from sternal angle + 5cm
Give 3 superficial veins of the scalp
1) Superficial temporal veins
2) Occipital veins
3) Posterior auricular veins
Describe venous drainage around the eye
Veins around eye unite at medial angle of eye to form angular vein which drains into the facial vein
Where is the Pterygoid venous plexus located?
In the infratemporal fossa
Where do facial veins drain?
IJV
What are dural venous sinuses?
Where do they form and where do they recieve blood from?
Endothelium-lined spaces between periosteal and meningeal layers of dura
Form at dural septae
Receive blood from large veins draining brain
Describe the connection between:
Venous Drainage of Scalp ⟷ Dural Venous Sinuses
What is the clinical significance?
Veins of scalp connect to diploic veins of the skull through several emissary veins and thus drain into dural venous sinuses
Emissary veins are valveless
Infection from scalp can spread to the cranial cavity and affect meninges
What are the 8 veins that drain the face? (hint: same as arteries they run with)
Describe the venous drainage of the head
What is the clinical significance?
Superior and inferior ophthalmic veins connect with the cavernous sinus
Spread of infection from face into brain
What is indicated by the arrow?
Cavernous Sinus
What is the Cavernous Sinus?
What is contained withinin it
Plexus of extremely thin-walled veins on upper surface of sphenoid
Inside cavernous sinus:
- ICA
- CN III (Oculomotor)
- CN IV (Trochlear)
- CN VI (Abducens)
- 2 branches of Trigeminal: (CNV1 ophthalmic & CNV2 maxillary)
What surrounds the pituitary gland
Cavernous Sinus
What is the drainage of the facial veins
What is the drainage of the deep facial veins
Facial Veins ⟷ Cavernous Sinus ⟷ Pterygoid Venous Plexus
Deep facial veins ➞ pterygoid venous plexus
Where can infection of the facial veins spread?
to dural venous sinuses
What is a Thrombophlebitis?
What may happen if it occurs in a facial vein?
Infected clot
Can travel to intracranial venous system
What is indicated on this image?
What is its significance
Danger triangle
Because of the special nature of the blood supply to the nose and surrounding area, it is possible (unlikely) for an infection from this area to spread to the brain
What artery supplies the dura and skull and what is this a branch of?
Middle meningeal artery
Branch of maxillary artery (1/2 terminal branchs of ECA)
Where does the MMA run in relation to the dura?
Runs superficial to dura mater
What is the Pterion and why is it important?
Pterion: where 4 bones meet (temporal, frontal, parietal and sphenoid bone)
Important area because it is weak and located under it is the MMA
What may a fracture of skull at Pterion cause?
Rupture of MMA because it pulls the periosteal dural layer off skull leading to Extradural (epidural) haemorrhage
What surgical procedure can be done to access the cranial cavity?
How is blood supply preserved?
Craniotomy
Bone and scalp flap reflected inferiorly to preserve blood supply
