Major arteries of head & neck: clinical

Question 1

what is the carotid sinus?

Answer 1

dilated portion of the common carotid and internal carotid arteries

Question 2

what does the carotid sinus contain?

Answer 2

specific sensory cells: called baroreceptors

Question 3

what do baroreceptors do?

Answer 3

detect stretch as a measure of blood pressure

Question 4

what feeds the information from baroreceptors to the brain?

Answer 4

glossopharyngeal nerve

to regulate blood pressure

Question 5

what can the baroreceptors be like in some patients?

Answer 5

hypersensitive to stretch

Question 6

what happens to patients who have baroreceptors hypersensitive to stretch? leading to?

Answer 6

external pressure on the carotid sinus can cause slowing of heart rate and a decrease in blood pressure - brain then becomes underperfused = syncope

Question 7

what should be advised against in patients with baroreceptors hypersensitive to stretch?

Answer 7

checking the pulse at the carotid triangle is not advised

Question 8

what is present external to the carotid sinus?

Answer 8

cluster of nervous cells called the carotid body

Question 9

what do the nervous cells (carotid body) do?

Answer 9

act as peripheral chemoreceptors - detecting the O2 content of the blood, and relaying this information to the brain to regulate breathing rate

Question 10

which arteries b=provide a dense blood supply to the scalp?

Answer 10

posterior auricular
occipital
superficial temporal arteries
(along with 2 branches of the internal carotid artery: supra-orbital and supratrochlear)

Question 11

what can injuries to the scalp result in?

Answer 11

excessive bleeding

Question 12

what do injuries to the scalp result in excessive bleeding?

Answer 12

1. walls of arteries are tightly and closely bound to the underlying CT of the scalp
2. numerous anastomoses
3. deep lacerations can involve epicranial aponeurosis

Question 13

why does ‘walls of arteries are tightly and closely bound to the underlying CT of the scalp’ result in excessive bleeding in injuries to the scalp?

Answer 13

this prevents the arteries from constricting to limit blood loss following injury or laceration

Question 14

why does ‘numerous anastomoses’ cause excessive bleeding in injuries to the scalp?

Answer 14

numerous anastomoses formed by the arteries produce a very densely vascularised area

Question 15

why do ‘deep lacerations can involve the epicranial aponeurosis’ result in excessive bleeding in injuries to the scalp?

Answer 15

involve the epicranial aponeurosis - which is worsened by the opposing pulls of the OCCIPITAL and FRONTALIS muscles

Question 16

how is bleeding to the scalp prevented from progressing to avascular necrosis?

Answer 16

the bony skull gets its blood from an alternative source (middle meningeal artery), so will not undergo avascular necrosis

Question 17

what is the middle meningeal artery a branch of?

Answer 17

maxillary artery

Question 18

what does the middle meningeal artery supply?

Answer 18

intracranial structures:

skull and dura mater

Question 19

what supplies extra-cranial structures?

Answer 19

external carotid artery and its branches

Question 20

what is dura mater?

Answer 20

the outer membranous layer covering the brain

Question 21

what is the weakest point of the skull?

Answer 21

pterion

Question 22

what does a fracture at the pterion result in?

Answer 22

injure / complete lacerate the middle meningeal artery

Question 23

what does fracture at the pterion injuring the middle meningeal artery result in?

Answer 23

blood to collect in between the dura mater and the skull, causing a dangerous increase in intra-cranial pressure

Question 24

what is an increase in intra-cranial pressure from blood collecting between the dura mater and skull called?

Answer 24

extradural haematoma

Question 25

what are the symptoms caused by an increase in intra-cranial pressure?

Answer 25

a variety of symptoms:

nausea, vomiting, seizures, bradycardia, limb weakness

Question 26

how do you treat minor increase in intra-cranial pressure?

Answer 26

treated by diuretics in minor cases

Question 27

how do you treat extreme haemorrhage causing intra-cranial pressure?

Answer 27

drilling burr holes into the skull

Question 28

what is the carotid sinus?

Answer 28

swelling at the bifurcation of the common carotid arteries

Question 29

what does swelling of the carotid sinus produce?

Answer 29

turbulent blood flow

Question 30

what does turbulent blood flow from swelling of the carotid sinus result in?

Answer 30

increases risk of atheroma formation in this area

within the tunica intima

Question 31

which artery is more susceptible to increase risk of atheroma formation?

Answer 31

internal carotid artery

Question 32

what does atherosclerotic thickening of the tunica intima of the internal carotid artery (/carotid sinus) result in?

Answer 32

reduce blood flow to the brain, resulting in neurological symptoms

Question 33

what are the neurological symptoms resulting from atherosclerotic thickening of the tunic intima?

Answer 33

headache, dizziness, muscular weakness

Question 34

if the blood flow to the brain is completely occluded, what will result?

Answer 34

a cerebral ischaemia (stroke)

Question 35

if atherosclerosis of the carotid arteries is suspected, what should be used to assess the severity of any thickening?

Answer 35

a Doppler study

Question 36

in severe cases, how should an atherosclerosis of the carotid artery be treated?

Answer 36

the artery can be opened, and the atheromatous tunica intima removed

Question 37

what is the process of artery being opened and atheromatous tunica intima removed called?

Answer 37

carotid endarterectomy