AT II: Carotid Triangle & Neuromuscular Structures

Question 1

Describe the positioning of the carotid sheath

Answer 1

Sheath runs from foramen of carotid canal (base of skull) to the aortic arch

Question 2

What are the contents of the carotid sheath?

Answer 2

Medially: Common carotid artery (Splits into Internal and External CA)

Laterally: Internal jugular vein

Posteriorly: CN X

Question 3

Where does the right common carotid artery branch from?

Answer 3

Branch of the Brachiocephalic trunk

Question 4

Where does the left common carotid artery branch from?

Answer 4

Directly from arch of aorta

Question 5

Where do the internal carotid artery & external carotid artery branch off the common carotid artery?

Answer 5

around C3/C4

Question 6

Where is the carotid sinus and what is the function?

Answer 6

enlargement/dilation at the bifurcation of common carotid artery which contains baroreceptors.

Monitors blood pressure and helps maintain it

Question 7

What is the nerve supply of the carotid sinus?

Answer 7

Innervated by CN IX (Glossopharyngeal) via carotid sinus nerve

& CN X (Vagus)

Question 8

Where is the carotid body and what is the function?

Answer 8

Small organ which houses chemoreceptors located at the bifurcation of CCA

Monitors blood O2, CO2, pH & Temp. Adjusts body to keep these stable

Question 9

What is the nerve supply of the carotid body?

Answer 9

Innervated by CN IX (Glossopharyngeal) via carotid sinus nerve

& CN X (Vagus)

Question 10

What are the branches of the external carotid artery?

Answer 10

• Superior thyroid artery
• Ascending pharyngeal artery
• Lingual artery
• Facial artery
• Occipital artery
• Posterior auricular artery (Posterior to ear)
• Superficial temporal artery
• Maxillary artery

Question 11

What veins drain into the Internal jugular vein?

Answer 11

• Inferior petrosal sinus
• Pharyngeal vein
• Occipital vein
• Facial vein
• Lingual vein
• Superior thyroid vein
• Middle thyroid vein

Question 12

Where does the IJV exit the skull from?

Answer 12

From the jugular foramen & enters the carotid sheath

Question 13

Where does the internal jugular vein lead to?

Answer 13

Joins onto brachiocephalic vein

Question 14

What veins drain into the external jugular vein?

Answer 14

• Posterior external jugular
• Transverse cervical vein
• Suprascapular vein
• Anterior jugular vein

Question 15

What is the origin of the EJV and what anatomical landmark does cross?

Answer 15

Begins at angle of mandible

Crosses over the sternocleidomastoid

Question 16

Where does the EJV drain to?

Answer 16

The subclavian vein

Question 17

Where do anterior jugular veins arise from and where do they drain into?

Answer 17

Run either side of the midline of neck

Drains into EJV; in some instances directly into subclavian vein

Question 18

Briefly describe the general course & distribution of CN IX (glossopharyngeal)

Answer 18

exits jugular foramen in skull, travels downward between IJV & ICA

Most of the nerve travels forward to oral cavity but some downward to CAROTID SINUS (& body), pharynx

Question 19

Briefly describe the general course & distribution of CN X (vagus)

Answer 19

exits jugular foramen in skull & travels downwards WITHIN carotid sheath (with IJV & CCA [ICA])

Branches to pharynx, and carotid body also leads to recurrent laryngeal nerves

Question 20

Briefly describe the general course & distribution of CN XI (spinal accessory)

Answer 20

Exits jugular foramen in skull, downwards between IJV & ICA then crosses lateral surface of IJV to descend to the postderior triangle of the neck.

Innervates SCM & Trapezius

Question 21

Briefly describe the general course & distribution of CN XII (Hypoglossal)

Answer 21

Exits hypoglossal canal, between IJV & ICA, crosses the ECA laterally on its way to the oral cavity.

Question 22

What is the transverse cervical nerve and what does it innervate?

Answer 22

Branch of of cervical plexus (C2, C3). Supply cutaneous innervation over the SCM & anterior triangle

Question 23

What does the ansa cervicalis innervate?

Answer 23

Anterior rami of C1-C3 - innervates infrahyoid muscles

Question 24

What is the brachial plexus and what does it innervate?

Answer 24

A trunk of nerves found in neck found at C5-T1

Question 24

What is the brachial plexus and what does it innervate?

Answer 24

A trunk of nerves found in neck found at C5-T1