The Carotid Triangle and Neurovascular Structures

Question 1

What is found in the carotid triangle?

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 XII

Question 2

What is found and where in the vascular compartment of the neck?

Answer 2

Medially - CCA, ICA and parts of ECA
Laterally - IJV
Posteriorly - CN X

Question 3

Where do the CCAs come from?

Answer 3

Right - branch of the brachiocephalic trunk
Left - direct branch from the aorta

Question 4

Where do the ICA and ECA branch from the CCA?

Answer 4

At C3/C4

Question 5

What is the carotid sinus?

Answer 5

Enlargement/dilation at bifurcation of CCA containing baroreceptors/pressoreceptors in wall of ICA

Question 6

What does the carotid sinus do?

Answer 6

It monitors blood pressure
Baroreceptors are sensitive to stretch
Helps keep blood pressure within homeostatic values

Question 7

What innervates the carotid sinus?

Answer 7

CN IX via carotid sinus nerve and CN X
APs travel from the baroreceptors through CN IX to the cardioregulatory and vasomotor centres in the medulla

Question 8

What is the carotid body?

Answer 8

Small organ (2-5mm) which houses chemoreceptors located at the bifurcation of the CCA near the carotid sinus

Question 9

What does the carotid body do?

Answer 9

Monitors blood O2, CO2, pH and temperature
Responds in emergency situations by increasing respiration, blood pressure and cardiac rate

Question 10

What innervates the carotid body?

Answer 10

CN IX via carotid sinus nerve and CN X
Afferent fibres from the carotid body travel to the cardioregulatory and vasomotor centres in the medulla

Question 11

What are the branches of the external carotid artery?

Answer 11

Superior thyroid
Ascending pharyngeal
Occipital
Lingual
Facial
Posterior auricular
Superficial temporal
Maxillary

Question 12

Which branches of the external carotid artery are terminal?

Answer 12

Superficial temporal
Maxillary

Question 13

Where does the IJV drain blood from?

Answer 13

Brain
Skull
Face
Part of the neck

Question 14

Where does the IJV run?

Answer 14

Continuation of the sigmoid sinus
Exits skull via the jugular foramen and enters the carotid sheath
Runs lateral to the CCA
Joins subclavian vein to become the brachiocephalic vein (L and R)

Question 15

Which veins drain into the IJV?

Answer 15

Inferior petrosal sinus
Pharyngeal
Occipital
Facial
Lingual
Superior thyroid
Middle thyroid

Question 16

Where does the EJV run?

Answer 16

Begins at angle of mandible, joining retro mandibular and posterior auricular veins
Crosses over SCM
Pierces into fascia to enter and drain into the subclavian vein

Question 17

Which veins drain into the EJV?

Answer 17

Posterior external jugular
Transverse cervical
Suprascapular
Anterior jugular

Question 18

Where does the anterior jugular veins run?

Answer 18

Arise near the hyoid bone and run on either side of the midline through subcutaneous tissue communicating across the midline via the jugular venous arch
Drains into EJV, will sometimes drain directly into the subclavian vein

Question 19

What does CN VII innervates in the neck

Answer 19

Cervical branch innervates platysma
Digastric branch innervates digastric
Supplies stylohyoid

Question 20

Where does CN IX run in the neck and what does it supply?

Answer 20

Exits the jugular foramen and travels downward between the IJV and ICA
Some branches travel downward to the carotid sinus and body, pharynx (sensory) and stylopharyngeus (motor)

Question 21

Where does CN X run in the neck?

Answer 21

Exits jugular foramen and travels downward within carotid sheath
Motor branch to the pharynx arises as well as a branch to the carotid body, the superior laryngeal nerve and a cardiac branch
Recurrent laryngeal nerves arise inferiorly near to the subclavian artery (R) or arch of aorta (L)

Question 22

Where does CN XI run in the neck and what does it supply?

Answer 22

Exits jugular foramen and travels downward between the IJV and ICA
Crosses the lateral surface of the IJV to descend to the posterior triangle of the neck
Innervates SCM and trapezius

Question 23

Where does CN XII run in the neck?

Answer 23

Exits the hypoglossal canal and is between the IJV and ICA
Crosses the ICA and ECA laterally on its way to the oral cavity
No branches to the anterior triangle of the neck

Question 24

Where does the transverse cervical nerve come from and what does it supply?

Answer 24

Anterior rami of C2, C3
Supplies cutaneous innervation over SCM and anterior triangle

Question 25

Where does the ansa cervicalis come from and what does it supply?

Answer 25

Anterior rami of C1-C3
Innervates infrahyoid muscles

Question 26

Where does the cervical plexus come from and what does it supply?

Answer 26

Anterior rami of C1, C2-C4
Supplies the infrahyoid muscles, diaphragm (via phrenic), skin of anterior/lateral neck and inferior head

Question 27

Where does the brachial plexus run and what does it branch into?

Answer 27

From C5 - T1
Branches in neck to dorsal scapular nerve, C5 branch to phrenic and suprascapular nerve