S3 Major Blood Vessels of the Head and Neck

Question 1

on the right side, where do the subclavian and common carotid arteries arise from ?

Answer 1

brachiocephalic trunk

Question 2

where do the vertebral, internal thoracic and thyrocervical arteries arise from ?

Answer 2

subclavian in the base of the neck

Question 3

where does the CCA bifurcates from ?

Answer 3

around C4

Question 4

describe route of vertebral artery

Answer 4

ascend in the neck through transverse foramina in cervical vertebrae 6-1 and pass through the foramen magnum
vertebral arteries supply the brain along with ICA

Question 5

describe route of Internal carotid artery

Answer 5

gives no branches off in neck

enters skull through carotid canal

Question 6

what are the borders of carotid triangle ?

Answer 6

Superior - posterior belly of digastric
Lateral - Anterior Sternocleidomastoid
Medial - superior belly of omohyoid

Question 7

what are the contents of the carotid triangle ?

Answer 7

Internal jugular vein

bifurcation of CCA at C4

Question 8

what is the carotid triangles clinical significance ?

Answer 8

surgical approach to CA or IJV, can access CN X and CN XII via this triangle, can palpate carotid pulse here, carotid sinus massage can lower heart rate

Question 9

where is clinical significance of the bifurcation of CCA ?

Answer 9

common site of atheroma formation
causes narrowing of the artery (stenosis)
rupture of the clot can cause an embolus to travel to brain causing TIA or stroke

Question 10

what is the carotid sinus ?

Answer 10

swelling at bifurcation ( internal CA) and also the location of baroreceptors for detecting changes in arterial BP

Question 11

what is the carotid body ?

Answer 11

peripheral chemoreceptors which detect arterial 02, massage in supraventricular tachycardia to stimulate baroreceptors to reduce BP. A hypersensitive carotid sinus may cause fainting upon pressure here.
common site of atherome due to turbulence

Question 12

describe route of ICA

Answer 12

enters skull through carotid canal in petrous part of temporal bone
turns medially and horizontally
enters cranial cavity the makes s- shaped bend
courses through the carvenous sinus

Question 13

what is the carvenous

sinus and what are its contents ?

Answer 13

plexus of extremely thin-walled veins on upper surface of sphenoid
Contents –> O TOM CAT
O- Oculomotor nerve
T- Trochlear nerve
O- Ophthalmic branch
M- Maxillary branch
C- Carotid artery
A- Abducens nerve
Lateral wall (S to I) : Oculomotor, Trochlear, ICA, Abducens
Transversing trigeminal branches : Ophthalmic (CNV1), Maxillary (CN V2)

Question 14

what is the route of the Ophthalmic artery ?

Answer 14

ICA – > Ophthalmic artery —–> Supra-orbital artery

Question 15

what are the branches of the external carotid artery ?

Answer 15

Six branches : SALFOPMS
Super Angry Lady Figured Out Post Menopausal Syndrome 
Superior Thyroid 
Ascending Pharyngeal
Lingual
Facial
Occipital
Posterior Auricular 
Maxillary (terminal)
Superficial Temporal(terminal)

Question 16

describe the blood supply to the scalp

Answer 16

rich blood supply with many anastomoses
largely branches of external carotid artery ( superficial temporal, posterior auricular, and occipital arteries) except supratrochlear and supraorbital arteries( branches of the ophthalmic artery) which arises from the ICA

Question 17

what is the clinical significance of blood supply to the scalp ?

Answer 17

Walls of arteries closely attached to connective tissue in scalp, limits constriction - can get profuse bleeding
Deep lacerations involve epicranial aponeurosis cause profuse bleeding because of opposing pull of occipitofrontalis
NOTE : BLOOD SUPPLY TO SKULL IS MIDDLE MENINGEAL ARTERY SO LOSS OF SCALP DOES NOT LEAD TO BONE NECROSIS

Question 18

where can facial artery pulse be felt ?

Answer 18

inferior border of mandible, anterior to the masseter muscle

Question 19

where do the superficial arteries of the face ?

Answer 19

all arise from the ECA except supra-orbital and supratrochlear from ICA (via ophthalmic)

Question 20

give examples of branches of the maxillary artery

Answer 20

many branches of supplying muscles and deeper structures in face - middle meningeal , sphenopalatine

Question 21

what is the blood supply to the Dura and Skull and its clinical significance?

Answer 21

Middle meningeal artery enters via the foramen spinosum and supplies skull and dura. Fracture of skull at pterion can rupture the middle meningeal artery - extradural haemorrhage, blood collects outside the dura

Question 22

Describe the superficial vein drainage of the scalp

Answer 22

superficial veins generally accompany arteries
- superficial temporal veins
- occipital veins
- posterior auricular veins
Supraorbital veins and supra trochlear veins united at medial angle of eye to form angular vein which drains into the facial vein

Question 23

Describe the deep venous drainage of the scalp

Answer 23

some deep parts of the scalp in temporal region have veins which drain into the pterygoid venous plexus

• veins of scalp connect to diploic veins of skull through several emissary veins and thus to dural venous sinuses
• emissary veins are valve less. infection from scalp can spread to the cranial cavity and affect meninges

Question 24

Describe the connection of facial veins with carvenous sinus and pterygoid venous plexus

Answer 24

veins of the face are valveless. at medial angle of eye , facial vein communicates with superior ophthalmic drains into carvernous sinus
deep facial veins drain into pterygoid venous plexus. Infection from facial vein can spread to dural venous sinuses.
The sigmoid sinuses continue as the internal jugular veins, leaving the skull through the jugular foramen

Question 25

what is the purpose of the lymphatic system ?

Answer 25

remove tissue fluid from the extracellular space back into blood circulation, return small proteins/fluids that leaked from capillaries, remove excess fluid from interstitial space, big role in immune defence and surveillance

Question 26

how does tissue fluid form ?

Answer 26

at the arteriole end, hydrostatic pressure> oncotic pressure and at the venule end oncotic pressure stays the same but the hydrostatic pressure has fallen, therefore there is a higher pull in than push out. Net filitration of fluid is not equal to net reabsorption of fluid. As some very small proteins also get pushed into the interstitium, but are not absorbed at the venule end so residual fluid remains

Question 27

Describe lymph fluid formation

Answer 27

Tissue fluid in interstitium enter lymphatic capillary to form lymph, combined with small proteins, lipids, damaged cells , bacteria and cancer cells. 3-4 litres per day. System is low pressure, there is no central pump. One directional flow.

Question 28

How lymph fluid form ?

Answer 28

Lymph vessels run closely to blood vessels and muscles, so they get pressed on contractions, pushing the fluid in one direction - passive constriction

Question 29

How does lymphatic system drains lymph into venous circulation

Answer 29

Right side down to diaphragm drains to right lymphatic duct which goes into right subclavian veins, left side and right side below diaphragm drains into thoracic duct which goes into left subclavian vein

Question 30

What is a lymphoedema and it’s causes ?

Answer 30

A chronic condition involving an abnormal collection of protein rich fluid causing tissue swelling due to a compromised lymphatic system. Non - pitting Causes : removal or enlarged LN, damaged to lymphatic system (e.g radiotherapy causing fibrosis of LN), lack of limb movement ( doesn’t cause but wont allow it to get better) congenital (e.g Milroy’s syndrome)

Question 31

Describe lymph nodes

Answer 31

- connective tissue structures with fibrous outer capsule and reticular connective tissue inside - highly organised centres of immune cells - lymphocytes (B AND T) and macrophages. B cell proliferation on infection causes LN enlargement - Lymph draining into lymph nodes may contain pathogens (e.g from an infected area of tissue) - all substances transported in lymph pass through > 1 lymph node, which act as a physical and phagocytic filter and are full of lymphocytes that activate and proliferate in response to antigens

Question 32

Describe lymphadenopathy

Answer 32

Enlarged LN, infection most common cause (tender and mobile) also from malignancy ( hard and non- tender)

Question 33

How are lymph nodes organised

Answer 33

Superficial (drain specific superficial areas and are usually more superficial) Deep ( receive drainage from number of regional nodes) Regional and terminal separated by investing layer of deep cervical fascia. Regions where lymph nodes may be palpable

Question 34

What are the superficial lymph nodes ?

Answer 34

``` submental submandibular preauricular postauricular occipital superficial cervical lymph nodes ```

Question 35

what are the cervical lymph nodes ?

Answer 35

Superifical cervical lymph nodes : superficial to External Jugular vein Posterior cervical lymph nodes : posterior to external jugular vein Anterior cervical lymph nodes : Anterior jugular vein

Question 36

are the superficial nodes palpable ?

Answer 36

may be readily palpable even if slightly enlarged

Question 37

what is the waldeyers ring ?

Answer 37

``` annular collection of lymphatic tissue (nodules) surrounding the entrance to the aerodigestive tracts. Responds to pathogens that may be ingested or inhaled. Consists of the tonsils : Pharyngeal tonsil (adenoids) Tubal tonsils Palatine tonsils Lingual tonsils ```

Question 38

what are the deep (terminal) cervical lymph nodes ?

Answer 38

lymph drains from superficial lymph nodes into the deep lymph nodes thus some diseases ( inflammation/ malignancy) may enlarge superficial or deep (main) cervical lymph nodes Deep to SCM closely related to IJV and carotid sheath 9. Jugulo-digastric 10. Jugulo-omohyoid 11. Supraclavicular lymph nodes (within supraclavicular fossa)

Question 39

describe the nature of supraclavicular lymph nodes

Answer 39

oversee transport of lymph from thoracic activity and abdomen Left node : drains abdomen and thorax - Virchow's Node (for GI malignancy) Right node : drains mid-section chest, oesophagus and lungs

Question 40

describe the nature of deep cervical lymph nodes

Answer 40

deep cervical lymph nodes are found in close relation to the IJV within the carotid sheath. Lymph fluid passing through the deep cervical lymph nodes drains into the subclavian vein