The Neck

Question 0

What is the key landmark in the neck? Innervation?

Answer 0

The sternocleidomastoid, CN XI

Question 1

What are the boundaries of the anterior triangle of the neck?

Answer 1

Superior: inferior border of the mandible

posterior: anterior border of the sternocleidomastoid
anterior: an imaginary midline drawn vertically through the neck.

Question 2

Which of these fascial divisions are related to the anterior triangle?

Answer 2

The investing layer forms the roof and the pretracheal layer (as well as the middle layer of cervical facsia that harnesses the infrahyoid mm.) forms the floor of the anterior triangle.

Question 3

What are the three divisions of the deep cervical fascia?

Answer 3

From superficial to deep:
the investing layer of deep cervical fascia
the pretracheal fascia
the prevertebral fascia

Question 4

Why is the lower extent of these fasciae clinically important?

Answer 4

These fascial layers extend down into the thorax and allow for “tracking” of pus/infection from the head and neck down into the thorax.

Question 5

What are the sensory branches of the cervical plexus?

Answer 5

The lesser occipital, great auricular, transverse cervical and supraclavicular nn. (note that C1 has NO sensory contribution to the plexus)

Question 6

Which spinal cord levels are involved in the cervical plexus?

Answer 6

C1-C4 ventral rami

Question 7

Be able to identify the regions on the neck they would innervate on a diagram

Answer 7

This diagram is on the bottom of page 324, is important, and is commonly used on the exam.

Question 9

Where is a cervical block administered? Why?

Answer 9

About 1/2 the way up the posterior border of the sternocleidomastoid. The bolus of anesthestic diffuses around the point of exit of the nerves of the cervical plexus from behind the muscle. This is ERBS POINT

Question 10

Be able to label a diagram indicating the various subdivisions of the anterior triangle.

Answer 10

Be able to define the boundaries of the submandibular (digastric), submental, carotid and muscular triangles (diagram on page 327).

Question 11

What are the boundaries of submandibular triangle? Main contents?

Answer 11

anterior and posterior bellies of the digastric and the inferior border of the mandible

the submandibular gland, facial artery and lymph nodes, mylohyoid (floor)

Question 12

What are the boundaries of the submental triangle? Main contents?

Answer 12

Submental: anterior bellies of contralateral digastric mm. and the hyoid bone

lymph nodes
Mylohyoid (floor)

Question 13

What are the boundaries of the carotid triangle? Main contents?

Answer 13

Carotid: posterior belly of digastric, anterior border of the sternocleidomastoid and the lateral border of the superior belly of the omohyoid

common carotid a., internal jugular v., vagus n., and hypoglossal n

Question 14

What are the boundaries of the muscular triangle? Main contents?

Answer 14

Muscular: medial border of the superior belly of the omohyoid, anterior border of the sternocleidomastoid and the imaginary vertical midline axis of the neck.

nothing - midline viscera located below the muscular (infrahyoid) floor.

Question 15

List the suprahyoid muscles and their innervation

Answer 15

1) Stylohyoid (facial n. - VII)
2) Posterior belly of digastric (facial n. - VII)
3) Anterior belly of digastric (n. to the mylohyoid - V3)
4) Mylohyoid (n. to the mylohyoid - V3)
5) Geniohyoid (C1 via CN XII).

Question 16

List the infrahyoid muscles and their innervation.

Answer 16

1) Sternohyoid
2) (superior belly of) omohyoid

3) Sternothyroid
(all by the ansa cervicalis)

4) Thyrohyoid (C1 via XII)

Question 17

Identify the superficial and deep groups of the infrahyoids and innervations

Answer 17

Superficial: sternohyoid and omohyoid (ansa);

Deep: sternothyroid (ansa) and thyrohyoid. (C1 via XII)

Question 18

What is the function (actions) of the suprahyoid mm.?

Answer 18

With the hyoid bone stabilized by the infrahyoids, the suprahyoids act as accessory mm. of mastication by assisting in depression of the mandible.

Question 19

What is the function (actions) of the infrahyoid mm.?

Answer 19

With the hyoid stabilized by the suprahyoids, the infrahyoids assist in elevating the larynx during swallowing.

Question 20

How is the ansa cervicalis formed?

Answer 20

From the descendens hypopglossus (superior root) from C1 fusing with the descendens cervicalis (inferior root) from C2/3.

Question 21

Over what structure is the ansa formed?

Answer 21

The internal jugular vein, which is within the carotid sheath.

Question 22

What does the ansa do?

Answer 22

It supplies 3 of the 4 infrahyoid muscles of the neck with motor innervation. (not thyrohyoid)

Question 23

Which branches form the descendens cervicalis?

Answer 23

Contributions from C2 and C3.

Question 24

Be able to label a diagram of the root of the neck - the branches off the first part of the subclavian a.

Answer 24

Diagram on page 332 - not generally on the written exam but very useful for the practical exam - don’t forget that the left side differs structurally from the right side diagrammed here.

Question 25

What are the contents of the carotid sheath?

Answer 25

The common carotid artery, internal jugular vein and the vagus nerve.

Question 26

Which of these contents of the carotid sheath lies on the right? on the left? posteriorly?

Answer 26

Medially - common carotid artery, Laterally - internal jugular vein and Posteriorly - vagus nerve.

Question 27

``` Be able to label a diagram similar to that depicting the branches off the external carotid artery (anterior and posterior aspects). ```

Answer 27

Remember the order in which these vessels arise from the external carotid and on which side: Anterior - superior thyroid, lingual, facial; Posteriorly - ascending pharyngeal, occipital, and posterior auricular. The two terminal branches are the maxillary and the superficial temporal.

Question 28

Which cranial nn. have an anatomical relationship with the branches of the external carotid?

Answer 28

The accessory (XI) swing posteriorly over the internal jugular vein. The hypopglossal (XII) swings anteriorly over the top of the external carotid a. and hooks just under the lingual artery.

Question 29

How do the carotid sinus and carotid body differ in location, function, innervation?

Answer 29

The carotid sinus is a swelling on the initial portion of the internal carotid. It is a baroreceptor regulating blood pressure of the thinner walled cerebral aa. It is innervated principally by the glossopharnygeal (CN IX). The carotid body is found in the birfucation of the common carotid, is a chemoreceptor that senses the CO2 content of the blood (increasing respiration if CO2 content is high) and is innervated by CN IX and X.

Question 30

List the sources of blood supply to the thyroid gland

Answer 30

Superior thyroid (off external carotid); inferior thyroid (off the thyrocervical trunk) and thyroidea ima artery (off the arch of the aorta).

Question 31

Why is the thyroid richly supplied with blood?

Answer 31

It is an endocrine organ (an organ that secretes hormones into the bloodstream).

Question 32

What is the relationship of the parathyroids to the thyroid gland? What is their blood supply?

Answer 32

They are embedded into the posterior region of the capsule of the thyroid gland. Blood supply from inferior thyroid artery

Question 33

Name one other clinically important relationship in the posterior region of the thyroid.

Answer 33

The recurrent laryngeal nerves run behind the lobes of the thyroid on their way to the larynx. Thyroidectomy with damage to these nerves results in either hoarseness (one nerve cut) to inability to speak (both nerves cut).

Question 34

Be able to label a diagram of the termination of lymphatic drainage at the root of the neck.

Answer 34

This diagram (on page 333 and 334) is important. You should be able to label it.

Question 35

What is the functional significance of the deep cervical group of lymph nodes?

Answer 35

They are the destination for all the superficial lymph drainage from the head and neck and are less palpable (deeper in location) than the superficial groups.

Question 36

Where are the deep cervical nodes located?

Answer 36

They run inside the carotid sheath close to the internal jugular vein.

Question 37

Which groups of superficial nodes can be palpated under the inferior border of the mandible?

Answer 37

The submental (under the apex) and the submandibular (under the lateral aspects).

Question 38

What regions do these submandibular nodes drain?

Answer 38

Tongue, lips, nose, oral regions and the submandibular glands.

Question 39

Why is the retropharyngeal space significant?

Answer 39

It is an important pathway for the spread of infection from the oral cavity down into the thorax.

Question 40

The thyroid gland descends from the _________ of the _______ via the _______

Answer 40

foramen cecum ; tongue ; thyroglossal duct

Question 41

Where does the thoracic duct terminate?

Answer 41

At the junction of the LEFT internal jugular vein and LEFT subclavian vein.

Question 42

Superficial venous drainage: the ___ and ___ veins drain into the retromandibular vein, which drains into the ______

Answer 42

superficial temporal vein; maxillary vein; external jugular

Question 43

What artery supplies the parotid gland and scalp?

Answer 43

Posterior auricular

Question 44

Pharyngeal plexus nerves (3)

Answer 44

1) CN XI via X (motor in gag reflex?) 2) CN IX (sensory in gag reflex) 3) Postganglionic sympathetic fibers (from superior cervical ganglion)

Question 45

The anterior scalene is attached to what and has what anterior and posterior to it?

Answer 45

Rib 1 scalene tubercle anterior to it: phrenic n, subclavian v posterior to it: brachial plexus, subclavian artery

Question 46

the posterior auricular artery supplies what?

Answer 46

parotid gland and scalp

Question 47

the occipital artery supplies what?

Answer 47

posterior scalp