Major Blood vessels of Head and Neck Flashcards
What does the internal carotid supply?
Brain (along with vertebral artery)
What three major structures does the external carotid supply?
Face, scalp, skull
Which artery mostly supplies the face and what vessel does it branch off of?
Facial artery, branch of ECA
Name the two small branches off ICA which help supply the face (in addition to the the facial artery from ECA)
ICA -> Ophthalmic a -> Supratrochlear and supraorbital branches
What specific branch supplies the skull and dura and what vessel does it branch off of?
Middle meninges artery, a branch of the maxillary (terminal branch of ECA)
Which vessel do the superficial veins drain into?
External jugular vein (EJV)
Which vessel do the deep veins drain into?
Internal jugular vein (IJV)
Where do SOME deep facial and scalp veins drain into (and where is it?)
Describe how this may be a potential route of infection and what may occur as a result
The cavernous sinus -> pterygoid venous plexus in the infratemporal fossa of the skull
If an infection spreads to the cavernous sinus it may cause a cavernous sinus thrombosis
Name the three major branches off the subclavian artery
- Vertebral
- Thyrocervical
- Internal thoracic
Name the four major branches of the thyrocervical trunk from inferior-superior
- Suprascapular
- Transverse cervical
- Inferior Thyroid
- Ascending cervical
Which vessels do NOT give off branches in the neck?
Common carotid and internal carotid (As it ascends to supply intra-cranial structures)
What vertebral level and anatomical structure are associated with the level where the common carotid bifurcates?
C4, superior border of thyroid cartilage
What vessels are within the carotid triangle and which nerves can be accessed through it?
Internal jugular vein
Bifurcation of common carotid
Can access the VAGUS n and hypoglossal n CN XII
What can be felt within the carotid triangle?
The carotid pulse
Where is the carotid sinus found and which receptors is it associated with?
It’s a swelling at the bifurcation of the common carotid at the beginning of the ICA. Has baroreceptors responsible for detecting changes (increases via stretching) in arterial BP
Where is the carotid body found and which receptors is it associated with?
Near bifurcation of carotid artery and has peripheral chemoreceptors which detect decreases in paO2 and pH (and increases in pCO2)
What might happen if a fatty deposit/atheroma located at the bifurcation of the carotid ruptures?
Embolus travels to the brain, may lead to a TIA or stroke
Name the 6 branches of the ECA
Some anatomists like freaking out poor medical students
Superficial temporal - terminal Ascending pharyngeal Lingual Facial Occipital Posterior auricular Maxillary - terminal Superior thyroid
Where can the facial artery pulse be felt/palpated? (Anterior to which muscle?)
About half way along the inferior border of the mandible, anterior to the masseter
Which five major branches supply the scalp and which vessels do they derive from?
OSPSS
- Occipital (ECA)
- Superficial Temporal (ECA)
- Posterior auricular (ECA)
- Supratrochlear (ICA)
- Supraorbital (ICA)
Does the loss of blood supply to the scalp lead to bone necrosis? Why or why not?
NO as the skull is mostly supplied by the middle meningeal artery (a branch off the maxillary)
What limits the constriction of arteries supplying the scalp?
The walls of the arteries are closely attached to the epicranial aponeurosis
Which two veins are responsible for superficial venous drainage to the head and neck and which is responsible for deep venous drainage?
Superficial:
- External jugular
- Anterior jugular
Deep: Internal jugular vein
Describe the path of the internal jugular vein
- Begins in cranial cavity as a continuation of the sigmoid sinus
- Exits skull via jugular foramen
- Descends down carotid sheath
- Posterior to sternal end of clavicle it joins with the subclavian vein to form the brachiocephalic vein
Name four general structures that the internal jugular v collects blood from
Skull, brain, superficial face, neck
What can the R IJV provide an indirect measure of and where might it’s pulsation be seen?
The central venous pressure and pressure in the R atria
Can look for vein’s pulsation under sternocleidomastoid and superior to the medial end of the clavicle
How is JVP measured and which vessel is used?
What is the normal JVP?
Use R IJV as it is straighter than the left and provides the best indication for R atrial pressure
- Lie patient at 45 degree angle with head turned to the left
- Measure height from sternal angle to highest level of jugular vein pulsation + 5cm
Since the R atria is 5cm below the sternal angle when the patient is at 45 degrees, and the height of JVP is 3cm above - a normal JVP should be 8cm.
Name three examples of superficial veins which accompany arteries
- superficial temporal
- occipital
- posterior auricular veins
What forms the angular vein and which vessel does it drain into?
Supraorbital and supratrochlear veins around the eye unite at a medial angle, drains into the facial vein
(The angular vein is the uppermost part of the facial vein)
Where do dural venous sinuses form?
At the dural septa; meningeal layer of dura mater sends 4 folds/septa inward
What are the dural venous sinuses?
Endothelium lined spaces between the periosteal (covers inner surface of skull) and meningeal layers of dura
How do veins of the scalp connect to the dural venous sinuses?
Superficial veins of the scalp connect to diploic veins (in the skull) through several emissary veins (which go through the skull) to drain into the dural venous sinuses
How might infection of the scalp spread to the skull -> cranial cavity and what could this cause?
Emissary veins (veins going through the skull and connecting the venous drainage between scalp and skull) are valveless, blood may then flow into the dural venous sinuses
This can cause osteomyelitis for example
How might infection spread easily from the face to the brain?
The superior ophthalmic vein; draining orbital roof and scalp and Inferior ophthalmic vein; draining orbital floor connects with the cavernous sinus
Where is the cavernous sinus and which vessel(s) and nerve(s) are in it?
On the upper surface of the sphenoid
Vessel: ICA
Nerves: CNIII (oculomotor), CNIV (trochlear), CN VI (abductens) + 2 branches of CN V trigeminal
-CN V1: Opthalmic
-CN V2: maxillary
What is thrombophlebitis?
Inflammation of the wall of a vein with an associated thrombosis
What might occur as a result of thrombophlebitis in the facial vein?
The facial vein has a connection with the cavernous sinus via the ophthalmic vein. Although most blood in the facial vein drains inferiorly, some blood passes into the cavernous sinus and so associated blood clots may pass into the intracranial venous system
Where is the pterygoid venous plexus and what is it connected to?
In the infratemporal fossa and connected with the cavernous sinus and pharyngeal venous plexus
What makes the pterion structurally significant?
It is thin part of the skull and point of weakness where the temporal, sphenoid, parietal and frontal bones join together
What might a fracture of the pterion result in?
A fracture may pull the dural layer off the skull and result in rupture to the middle meningeal artery (as the pterion is directly anterior to this vessel) -> this can cause an extradural (epidural) hemorrhage because the MMA runs SUPERFICIAL to the dura mater which exerts pressure on the underlying cerebral cortex
What is a craniotomy and how is it used?
The bone and scalp flap are reflected inferiorly (to not disturb the MMA) and gain access to the cranial cavity
Where do the R and L common carotids originate from?
R common carotid: bifurcation with the R subclavian at the R sternoclavicular joint to form the brachiocephalic trunk; which comes off the aorta
L common carotid: directly from the arch of the aorta
Which common carotid is longer and why?
The L common carotid as it courses ~2cm in the superior mediastinum before entering the neck
Where anatomically does the common carotid begin and terminate? What else is its ‘course’ known as?
Also known as the carotid line
Begins below the sternoclavicular joint and terminates midway between the angle of the mandible and the mastoid process of the temporal bone
Identify the ECA’s two TERMINAL branches, where are these branches given off
*including which specific structures are ANTERIOR at this bifurcation
Superficial temporal and Maxillary arteries are terminal. They are given off within the parotid gland which is posterior to the facial nerve and retromandibular vein
Compare the appearance of an epidural vs intradural hemorrhage
Epidural: pushes more on the brain
Intradural: more of a crescent shape
Which cranial nerve supplies occipitofrontalis?
CN VII Facial
Where can the superficial temporal artery be felt? How would it feel in giant cell arteritis (most common adult vasculitis)
As it passes over the zygomatic arch just in front of the auricle.
In giant cell arteritis it can feel prominent, tender, pulseless and knotted
Why isn’t the EJV used to measure JVP?
It’s pulsations are less accurate
In which condition is the JVP commonly raised?
RHF
List 5 ways in which the carotid pulse can be differentiated from the JVP
- Obliterated with pressure
C Pulse - no
JVP - yes - Hepatojugular reflux
C Pulse - unaffected
JVP - positive - Change with posture and respiration
C pulse - unchanged
JVP - changes - How many pulsations per systole
C pulse - single
JVP - double - Palpable pulsations?
C pulse - palpable
JVP - not palpable
Would venous pulses increase or decrease in Mitral valve disease, why?
Increase, as MV disease increases pressure in the pulmonary circulation and the R side of the heart
Apart from thoracic pain, what other complaint might a patient with an undiagnosed aneurysm of the arch of the aorta present with?
Since the L recurrent laryngeal nerve loops around the aortic arch, may present with hoarseness of voice
What will unilateral palsy of the L recurrent laryngeal nerve result in?
Ipsilateral paralysis of vocal cord and thus hoarseness of voice
What physiological response would arise if your were to put pressure on the carotid pulse in the area of the carotid sinus and why?
The carotid sinus (a swelling on the ICA at its bifurcation from ECA) has baroreceptors which detect increases in arterial BP. Stimulation/pressure will send afferent messages via the glossopharyngeal n (CN IX) to the spinal cord and pons, which will send efferent parasympathetic impulses to the heart via VAGUS to slow HR
Which nerve carries afferent information from baroreceptors located at the aortic arch?
Vagus n
What is the name given to the procedure involving rubbing the neck in the region of the carotid sinus? What condition does it treat and what can it be used to diagnose?
Carotid sinus massage
Treats supraventricular tachycardia (due to baroreceptors which will trigger decrease in HR)
Also used to diagnose carotid sinus syncope
Why must one listen to the neck with a stethoscope before performing a carotid sinus massage?
MUST listen for a bruit as it suggests an atherosclerotic plaque, if a CSM were to be performed it may lead to plaque rupture and stroke
Define the term ecchymosis
Bruising produced by extravasated of blood into the subcutaneous tissue
Which division of the common carotid artery supplies the area of skin of the forehead above the eye?
The superficial temporal artery (branch of ECA) and the terminal branches of the ophthalmic artery (branch of ICA) which are the supraorbital and supratrochlear
Which site of the common carotid is a common place for atherosclerotic plaque formation?
It’s point of bifurcation
