5 - Anterior triangle and neurovascular structures

Question 1

What is contained in the carotid triangle? (8)

Answer 1

• thyroid gland
• larynx
• pharynx
• carotid sheath
• branches of cervical plexus
• superior root of ansa cervicalis
• deep cervical lymph nodes
• parts of CN XI and CN XII

Question 2

What are the contents of the carotid sheath?

Answer 2

Medially
- common carotid artery
- internal carotid artery
- external carotid artery

Laterally
- internal jugular vein

Posteriorly
- CN X

Question 3

Where does the carotid sheath run?

Answer 3

Foramen of carotid canal to aortic arch

Question 4

Describe the course of the right common carotid artery.

Answer 4

• brachiocephalic trunk branches from the aortic arch
• CCA branches from brachiocephalic trunk
• ICA and ECA branch from CCA at C3/C4 level

Question 5

Describe the course of the left common carotid artery.

Answer 5

• CCA branches from the aortic arch
• ICA and ECA branch from CCA at C3/C4 level

Question 6

Describe the course of the internal carotid artery and what it supplies.

Answer 6

• no branches in the neck
• ascends to brain via the carotid canal
• provides anterior circulation to the brain

Question 7

What is the carotid sinus?

Answer 7

• enlargement/dilation at the bifurcation of CCA
• contains baroreceptors/pressoreceptors in the wall of the ICA
• monitors blood pressure

Question 8

What is the innervation of the carotid sinus?

Answer 8

• CN IX via carotid sinus nerve
• CN X
• action potentials travel to the medulla

Question 9

What is the carotid body?

Answer 9

• small organ which houses chemoreceptors
• located at the bifurcation of CCA
• monitors blood gases

Question 10

What is the innervation of the carotid body?

Answer 10

• CN XI
• CN X
• afferent fibres travel to the medulla

Question 11

What are the branches of the ECA? (8)

Answer 11

• superior thyroid
• ascending pharyngeal
• occipital
• lingual
• facial
• posterior auricular
• superficial temporal
• maxillary

Question 12

What does the ECA supply?

Answer 12

Structures that are external to the cranium

Question 13

Which branches of the ECA are found in the carotid triangle?

Answer 13

• lingual artery
• superior thyroid artery
• occipital artery
• ascending pharyngeal

Question 14

What do the terminal branches of the ECA supply?

Answer 14

• scalp (excluding forehead and orbit)
• supplied by middle meningeal artery which is a branch of the maxillary

Question 15

What are the terminal branches of the ECA?

Answer 15

• maxillary
• superficial temporal

Question 16

Where does the middle meningeal artery enter the cranium?

Answer 16

Foramen spinosum

Question 17

What does the IJV drain?

Answer 17

• brain
• skull
• face
• parts of neck

Question 18

Describe the course of the IJV.

Answer 18

• continuation of the sigmoid (venous) sinus
• exits skull via jugular foramen
• enters carotid sheath
• runs laterally to the CCA
• joins subclavian vein to form the brachiocephalic vein (both sides)

Question 19

Which veins drain into the IJV? (7)

Answer 19

• inferior petrosal sinus
• pharyngeal
• occipital
• facial
• lingual
• superior thyroid
• middle thyroid

Question 20

What is the inferior bulb of the IJV and where is it located?

Answer 20

• dilation which has valves
• prevents back flow when upside down or there is an increase in thoracic pressure
• located in the jugular foramen

Question 21

Where is the superior bulb of the IJV?

Answer 21

Petrosal sinus

Question 22

What muscles runs across the IJV?

Answer 22

Superior belly of the omohyoid

Question 23

What does the EJV drain?

Answer 23

• scalp
• face
• superficial neck

Question 24

What veins drain into the EJV? (4)

Answer 24

• posterior external jugular
• anterior jugular
• transverse cervical
• suprascapular

Question 25

Describe the course of the EJV.

Answer 25

- begins at angle of mandible - descends posteriorly and crosses SCM - pierces fascia to drain into the subclavian vein

Question 26

Describe the course of the AJV.

Answer 26

- arises at hyoid bone - runs along the midline through subcutaneous tissue - creates a communication across the midline with the opposing AJV, forming the jugular arch - drains into the EJV

Question 27

What does the facial nerve innervate in the neck?

Answer 27

Cervical branch - platysma Digastric branch - digastric Also supplies the stylohyoid muscle

Question 28

What does the glossopharyngeal nerve innervate in the neck?

Answer 28

- carotid sinus and body - pharynx - stylopharyngeus

Question 29

Where does the glossopharyngeal nerve exit the skull?

Answer 29

Jugular foramen

Question 30

What does the vagus nerve supply in the neck?

Answer 30

- pharynx - carotid body - recurrent laryngeal nerves

Question 31

Describe the course of the recurrent laryngeal nerves.

Answer 31

- both branch from the vagus nerve - right loops around the subclavian artery - left loops under the aortic arch

Question 32

What does the accessory (spinal) nerve supply in the neck?

Answer 32

- SCM - trapezius

Question 33

Where does the accessory (spinal) exit the skull?

Answer 33

Jugular foramen

Question 34

What does the transverse cervical nerve supply?

Answer 34

- branch of anterior rami of C2 and C3 - supplies cutaneous innervation to SCM and anterior triangle

Question 35

What does the ansa cervicalis supply?

Answer 35

- anterior rami of C1-C3 - innervates infrahyoid muscles

Question 36

What does the cervical plexus supply?

Answer 36

- anterior rami of C1-C4 - infrahyoid muscles - diaphragm (via phrenic) - skin of anterior and lateral neck - inferior head

Question 37

Where is the brachial plexus located?

Answer 37

C5-T1

Question 38

Which branches of the brachial plexus are located in the neck?

Answer 38

- dorsal scapular nerve - C5 branch to phrenic - suprascapular