Vasculature of the H&N Flashcards
what makes up the vascular part of the cardiovascular system
blood vessels - arteries - veins - capillaries lympthatic vascular system
what is the role of the lympthatic vascular system
- drains fluid that has leaked out of capillaries and into the surrounding tissues
- returns it to the venous system of cardiovascular system by draining veins in the lower / base of neck
on which side does the lymph (tissue fluid when in lympthatic vessels) drain
- mainly into the left = most of body and head
- some on right = right upper limb and right side of head and chest
what happens if tissue fluid isnt drained
tissues swell
what is the name of a condition where swelling is caused by blockage of lymphatic drains thus tissue build up
ELEPHANTISIS - a form of lymphodema (swelling caused by the accumulation of tissue fluid / lymph)
in what other system does the lymphatic system play a key role
immune system - immune surveillance and response
list the arteries of the head and neck
- aorta
- braciocephalic
- right and left subclavian
- right and left common carotid
- right and left internal carotid
- right and left external carotid
describe the aorta
- large
- carries oxygenated blood out of heart
- gives off vessels to head, neck, upper limbs before passing inferiorly to supply rest of body
describe the braciocephalic artery (aka braciocephalic trunk)
- 1st large vessel to emerge from aorta
- supplies upper limb (latin brachium = arm) , head, neck (latin cephalicus = head)
- on RHS ONLY
where and which 2 arteries does the braciocephalic artery divide into
runs up + laterally to root of neck where divides into 1) right subclavian
2) right common carotid
describe the right subclavian artery
- supplies upper limb
- inferior to clavicle
describe the right common carotid artery
- main blood supply to head and neck
where and which 2 arteries does the common carotid artery divide into
just below hyoid bone SO at the level of the adams apple / larangeal prominence
1) internal carotid
2) external carotid
- SAME happens on the LHS
describe the internal carotid artery
- has NO branches in the neck
- supplies contents of the cranial cavity (most of brain - main blood supply to brain) and comes back out of brain to supply structures in upper face (contents of orbit like eye - ophthalmic artery, skin on forehead, anterior scalp and nose)
- goes through foramen in base of skull, branches once inside skull SO its branches mainly lie inside the cranial cavity
describe the external carotid artery
- MANY branches in neck and facial region
- ALL blood travelling to oral region passes through this
- main blood supply to face below orbits + scalp
what happens on the LHS which makes the two sides asymmetrical
left subclavian and common carotid branch directly from the aorta
what is the name for the splitting of the common carotid arteries into internal and external carotid arteries
and what are the internal and external carotid arteries to the common carotid arteries
CAROTID BIFURCATION
they are the terminal branches (parent vessel doesn’t continue with same name beyond branching point)
what are the eyes classed as
an outgrowth from the brain
retina is part of the CNS
what nerves does the trigeminal ganglion branch into
- ophthalmic
- maxillary
- mandibular
name 3 branches of the external carotid
- lingual artery
- maxillary artery (a terminal branch of it)
- facial artery
describe the facial artery
- comes round bottom edge of mandible
- supplies lips, other soft tissues of anterior face, up toward medial aspect of orbit
- ends at medial corner of eye
which vessel supplies blood to mandibular teeth
- inferior alveolar artery (branch of maxillary artery)
- as it runs down after branching to enter mandibular foramen (on medial aspect of ramus - along with IA nerve and IA vein)
- once inside mandible it runs through a canal in the bone sending branches to teeth + associated structures as it goes through here
what does the IA artery do once it reaches the end of the mandible
- sends a branch that passes out through the mental foramen
what is the role of the lingual artery
- direct branch off the external carotid in upper neck
- supplies the tongue and nearby structures (in floor of mouth, gingivae on lingual side of teeth)
which artery supplies all but the anterior upper teeth and where does this arise
- posterior superior alveolar artery
- goes into maxilla, runs through bone then divides to supply them
- variable in exactly what teeth it supplies
- branch of maxillary artery = after giving off IA artery, it runs anteriorly through deep tissues of face giving this branch as it reaches the posterior aspect of the maxilla
which artery supplies the anterior upper teeth and where does this arise
- anterior superior alveolar artery
- branch of the infraorbital artery which passes under the eye and comes out through IO foramen (branch of maxillary artery given off after the posterior equivalent)
which artery supplies the palate and where does this arise
- descending palatine artery
- runs down towards the palatine region where it divides
- branch of maxillary artery which carries on medially after IO artery, giving this off just before reaching posterior aspect of maxillae
which 2 branches does the descending palatine artery give off and what do these supply
1) greater palatine artery
- goes anteriorly to supply hard palate + associated gingivae
2) lesser palatine artery - goes posteriorly to supply soft palate
what regions does / doesnt the greater palatine artery supply
where does it run and what does this mean if it is broken
- supplies mucosa of hard palate and palatine gingiva of upper teeth
- DOES NOT supply teeth
- goes through INCISIVE foramen (behind incisors) in hard palate, ends up in nasal cavity
- SO causes a nose bleed if broken
what does the greater palatine artery run with
greater palatine nerve (branch of maxillary nerve - 2nd division of the trigeminal nerve)
(lesser artery runs with lesser nerve)
where does the lesser palatine artery run to supply the soft palate
- back through a different hole in the bone (soft palate has no bones in it)
list the veins of the head and neck
1) superior vena cava
2) right and left brachiocephalic veins
3) right and left subclavian veins
4) right and left internal jugular veins
which large veins are responsible for draining most of the area (cranial cavity and areas of face and neck) and where do they run
- internal jugular vein
- run down each side of neck, close to common carotid arteries (lateral to larynx, hyoid bone, trachea, thyroid gland)
how are the internal jugular veins different from the common carotid arteries
common carotid = run up to the carotid bifurcation and DO NOT branch before it
internal jugular = has TRIBUTERIES draining into it
what are tributeries
smaller veins which drain blood into bigger veins
where do the internal jugular veins run
- down sides of neck
- meet the subclavian veins (come from upper limbs) at base of neck
- join with the subclavian veins to form the braciocephalic veins
where do the right and left brachiocephalic veins run
- come together just right of the midline
- to form the superior vena cava
what is the role of the external jugular vein and where does it run
- helps internal jugular drain blood from the head (BUT very little from cranial cavity)
- smaller than but runs parallel to internal
- does NOT emerge from cranial cavity, runs down side of neck until joining the subclavian vein
what separates the internal and external jugular veins
- the sternocleidomastoid muscle (runs obliquely from behind ear down towards the midline at the base of the neck anteriorly)
- external lies just underneath skin covering this muscle (superficial to muscle itself) and internal is deep to it
give an example of a tributery and what it drains
the facial vein
- drains blood OUT of superficial structures supplied by facial artery on anterior part of face
why can we not say that blood from the face passes through either IJV OR EJV
- tends to pass through BOTH
- retromandibular vein runs behind the mandible, branching at angle of mandible
- has a posterior branch which goes into EJV and anterior one which joins the facial vein before running into IJV
we have seen that many arteries are accompanied by veins with the same name BUT where does this correlation break down and what is the name of this structure
- in region just posterior to maxilla
- the PTERYGOID VENOIUS PLEXUS (does not have an arterial equivalent)
what is the pterygoid venous plexus and where does it lie
- loose network of interconnecting veins (plexus) that other veins drain into
- blood filled space
- lies posterior to mandible, behind maxilla + close to maxillary artery and pterygoid plates of sphenoid bone + pterygoid muscles
what does the pterygoid venous plexus receive
veins draining upper teeth, palatine veins, superior and inferior alveolar veins
which important space does the pterygoid plexus also receive veins from
- the cavernous sinus (blood filled space in the cranial cavity)
what property do veins from the cavernous sinus have and what does this mean
- NO valves
- blood can drain either way
- SO potential to transmit infection into the cavernous sinus (if introduce infection into the pterygoid venous plexus it can spread through these communicating veins into the cavernous sinus)
which serious disease can this infection cause
- cavernous sinus thrombosis + even death
which important structures run through the cavernous sinus and what does this mean for infection
- maxillary nerve, internal carotid artery etc
- AND other structures in the head drain down into it SO infection could go in the opposite direction
after running through the pterygoid venous plexus where does the blood go
1) into maxillary vein
2) then to retromandibular vein
3) then into external and internal jugular veins for transport down neck, back to heart
for which procedure is the venous plexus clinically important and why
- posterior superior alveolar nerve block procedure
- anaesthetic solution injected posterior to maxilla
what is the potential risk with the posterior superior alveolar nerve block procedure
injecting where the venous plexus is located
SO possible for the needle to pierce to plexus and introduce infection
it is ALSO possible to pierce the maxillary artery (lies in this area, runs through infratemporal fossa) causing bleeding and swelling on the affected side
what could be caused if anaesthetic was injected into the blood stream (INFRAARTERIORLY) of the maxillary artery
systemic toxicity
how would piercing the venous plexus introduce infection
potentially transfer microorganisms from the oral cavity into it and these may end up in the cranial cavity
what is another way of introducing infection to the pterygoid venous plexus and HOW
popping spots located on the anterior aspect of the face
can force infected pus into the facial vein which drains blood from this area, then through the deep facial vein to the pterygoid plexus where it has the potential to go up into the cranial cavity (cause serious disease + death)
what are lymph nodes connected by are where are these present in the neck
lymphthatic vessels
chain of lymph nodes run along IJV
what doesnt the brain have
lymphthatics
what do the lymphatics drain
most of the soft tissues of the body
why is tissue fluid forced out of capillaries
- as blood is forced under pressure through capillaries high pressure blood in them leaks out through capillary walls
- cells in blood cannot leak out BUT fluid they are suspended in does through thin vessel walls to surrounding tissue
what does tissue fluid deliver
dissolved nutrients to tissues
what are the lymphatic vessels
- network of fine vessels found throughout most tissues
- form progressively larger channels
- finally deposit collected tissue fluid (lymph) into veins at base of neck
what are lymph nodes and what is their role
“sacks of immune cells” / swellings found along the lengths of lymphatic vessels (a few mm in diameter - easily made out)
filter lymph - immune cells in them detect foreign antigens as it passes through them triggering an immune response
which 2 immune cells are found in lymph nodes and what is their response
1) phagocytes - digest and destroy
2) lymphocytes - produce antibodies
- work together generating a coordinated immune response
how are lymph nodes arranged
- arranged into superficial and deep chains
- predictable arrangement
what causes lymph nodes to swell
proliferation of immune cells in infection
how does lymph travel
node to node through lymphatic vessels
where does the lymphatic duct run
- up from abdomen collecting lymph
- joins venous system where brachiocephalic vein is formed
list some superficial lymph nodes of the head and neck found in small clusters around the base of the head which form a “ring” of nodes in the superficial tissues around the head
- sub-mental nodes = under chin
- sub-mandibular nodes = under mandible
- around parotid glands
- mastoid nodes = behind ear, near mastoid process
- occipital nodes = at back of head where it joins neck
what other superficial nodes can be identified
those draining down alongside EJV
what drains into superficial nodes
blood from superficial structures
some groups of them are attached (ie some drain from submental to submandibular)
which clearly defined set of nodes is found in the neck
- deep jugular chain
- located along length of internal jugular vein
- because lymph draining into superficial nodes generally passes to deeper nodes, the nodes in this chain receive lymph directly from deeper areas of face + neck AND are drained into by many superficial nodes
where does lymph from deep jugular chain drain
back into venous system where brachiocephalic vein is formed
where does lymph from head and neck drain
to a trunk which tends to joim thoracic duct before dumping into venous system
what is the latin word for vessel which ‘vascular’ is derived from
VASCULUM
