HEAD & NECK OVERVIEW

Question 1

Describe the pathway of the olfactory nerve.

Answer 1

CN I > Anterior Cranial Fossa (ACF) > Cribiform Plate > Nasal Cavity

Question 2

Describe the pathway of the optic nerve.

Answer 2

CN II > Middle Cranial Fossa (MCF) > Optic Canal > Orbit

accompanied with the ophthalmic artery

Question 3

What cranial nerves carry parasympathetic fibers?

Answer 3

Cranial nerves 3 occulomotor, 7 facial, 9 glossopharyngeal and 10 vagus carry PSNS fibers.

Question 4

What three cranial nerves exit the skull through multiple openings?

Answer 4

Cranial nerves 5 trigeminal, 7 facial and 9 glossopharyngeal exit through multiple openings in the skull.

Question 5

What are the borders of the posterior cervical triangle? What structures can be found in them?

Answer 5

The posterior border of the sternocleidomastoid, the anterior border of the trapezius and the clavicle are the borders of the posterior cervical triangle. Structures heading to the upper limb such as: trunks of the brachial plexus, scalene muscles, phrenic nerve and spinal accessory nerve can be found here.

Question 6

What are the borders of the anterior cervical triangle and what structures can be found in it.

Answer 6

The borders: midline of the neck (sternohyoid), anterior border of SCM and posterior belly of digastric muscle. Structures found here are directed towards the head, neck and thorax. These include the trachea and esophagus.

Question 7

What muscles border the scalene interval and what structures come out of it?

Answer 7

The anterior and middle scalene muscles border the interval. The subclavian artery and rami of the brachial plexus emerge from it.

Question 8

Describe thoracic outlet syndrome.

Answer 8

Compression of structures within the scalene interval lead to nerve pain or a diminished radial pulse when the head is turned. Trunks of the brachial plexus and branches of the subclavian artery can be affected.

Question 9

List the order of the layers of fascia from superficial to deep in the neck region. What is a clinically significant feature of the deep cervical fascia?

Answer 9

Skin > Superficial fascia > investing fascia > 2 Pretracheal fascias + 2 Prevertebral fascias.
Limits the spread of infectious pus and has natural cleavage planes for surgery.

Question 10

Define the buccopharyngeal fascia.

Answer 10

This is the posterior wall of the pretracheal fascia. It invests the constrictor muscles of the pharynx and runs parallel to the carotid sheath.

Question 11

Define the retropharyngeal space and its clinical significance.

Answer 11

This space lies between the buccopharyngeal fascia and prevertebral fascia. It enables the respiratory tract to slide up and down. Streptococcus pneumonia infection can spread down into the thorax, thus increasing the risk for infection in that region. Surgeons can use this space to take out the cervical HNPs via Anterior Cervical Disc Replacement.

Question 12

What 3 structures are contained within the carotid sheat and how are they oriented?

Answer 12

The internal jugular vein is lateral, the common carotid artery is medial and the vagus nerve is posterior within the carotid sheath.

Question 13

What is the clinical significance of the axillary sheath?

Answer 13

This is an evagination of the prevertebral fascia around the brachial plexus trunks as it buds out towards the upper limbs, emerging from the scalene interval. Through this sheath, surgeons can apply an anesthetic block to the entire upper limb.

Question 14

Where does the common carotid artery branch off from? What is the difference between the external and internal carotids?

Answer 14

The common carotid artery branches off from the subclavian artery and bifurcates @ C4. The internal carotid has the carotid sinus, goes inside the skull and DOES NOT branch in the neck; whereas, the external carotid supplies the structures of the neck.

Question 15

Compare/contrast the carotid body from the carotid sinus.

Answer 15

The carotid body is located at the crotch of the bifurcation and contains chemoreceptors to monitor O2/CO2 levels from cranial nerve IX. The carotid sinus is located at the internal carotid artery and contains baroreceptors. It monitors BP to signal CN IX to brain stem that slows down the HR via vagus nerve.

Question 16

Where are the three places at the highest risk for stenosis due to atherosclerosis? What device can help detect this before symptoms present in a patient?

Answer 16

Atherosclerosis occurs at bifurcation points due to low shear. They occur at the carotid bifurcation, left coronary artery and abdominal aorta. This disease is irreversible with age and can be seen with Doppler ultrasound.

Question 17

What vein drains the brain?

Answer 17

Internal jugular vein drains the brain. It dives deep into the head and neck and later joins the subclavian vein to form the brachiocephalic vein.

Question 18

What are the 4 cranial nerves found in the neck and what do they innervate?

Answer 18

Cranial nerves 9-12:
Glossopharyngeal - carotid body/ sinus, posterior 1/3 tongue, pharynx, muscles for swallowing
Hypoglossal - runs to the floor of the mouth superior to the hyoid;
Vagus - within the carotid sheath to modulate heart rate;
Accessory - heads into the SCM and trapezius muscles to innervate them

Question 19

The sympathetic trunk in the neck is located along _______ ganglia. At this level there are NO _____________ nerves but only _____ ramus communicans. Stellate ganglia have white ramus communicans and are found in the _________ space.

Answer 19

Cervical ganglia;
No preganglionic nerves;
Only gray ramus communicans;
Retropharyngeal space

Question 20

What types of ganglia lie on the carotid artery and what are they responsible for doing?

Answer 20

Superior cervical ganglia hang out on the carotid artery and they are responsible for vasoconstriction of vessels, especially in the nasal cavity.

Question 21

Where does the vertebral artery enter the spine and what do the left and right branches merge into when they meet at the external acoustic meatus?

Answer 21

Vertebral arteries enter transverse foramina @ C6 and ascend until they merge into the Basilar artery in the skull.

Question 22

Compare and contrast the dorsal and ventral rami of the neck’s cervical spinal nerves.

Answer 22

Dorsal rami innervate deep cervical muscles on the posterior neck. Ventral rami includes the cardiac plexus (C1-4), Phrenic nerve (C3-5) and most of the Brachial plexus (C5-C8).

Question 23

What are some adverse effects to performing a thyroidectomy?

Answer 23

The removal of the thyroid occurs in case of inflammation or a tumor. Unfortunately, this may damage nearby laryngeal nerves temporarily which leads to the paralysis of vocal chords. On average, patients have to whisper for the next 6 months post-op.

Question 24

Structures of the head drain into what lymphatic nodes in the neck?

Answer 24

Deep Cervical nodes located near the internal and external jugular veins.