Anatomy of the Thyroid Gland

Question 1

At what vertebral level does the larynx become the trachea

Answer 1

C6

Question 2

What 2 structures is the thyroid gland closely related to in the anterior neck

Answer 2

The larynx and the trachea

Question 3

What does the thyroid gland usually consist of

Answer 3

2 lateral lobes (right and left) and an isthmus

Question 4

What is the isthmus

Answer 4

A narrow connecting band

Question 5

What do the lobes of the thyroid gland attach to

Answer 5

The lateral aspects of the thyroid and cricoid cartilages and to the trachea

Question 6

What direction will the thyroid gland move when we swallow

Answer 6

Same as the larynx and the trachea

It will move superiorly then inferiorly

Question 7

Where are the 4 parathyroid glands located

Answer 7

Not the posterior surfaces of the thyroid gland’s lateral lobes

Question 8

What cartilage is located superiorly to the cricoid cartilage

Answer 8

The arytenoid cartilage

Question 9

Where does the pyramidal lobe most commonly originate from

Answer 9

The left lateral lobe of the thyroid gland

Question 10

Where doe most pyramidal lobes superiorly attach to

Answer 10

the thyroid cartilage

Question 11

Some pyramidal lobes may extend as far superiorly as where?

Answer 11

The hyoid bone

Question 12

Where does the thyroid gland begin its development

Answer 12

As a midline epithelial proliferation at the junction between the anterior 2/3rd and the posterior 1/3 of the tongue

Question 13

Where does the gland migrate to

Answer 13

Migrates inferiorly whilst remaining attached to the tongue to the thryoglossbal duct

Question 14

When does the thyroid gland reach its final position

Answer 14

7th week of development

Question 15

Where might the pyramidal bone be found

Answer 15

Anywhere along the migratory path of the thyroid gland

It is an ectopic thyroid gland tissue

Question 16

What encapsulates the trachea, the oesophagus and the thyroid gland

Answer 16

A layer of deep neck fascia - pre tracheal fascia

Question 17

What muscle can be found in the superficial fascia

Answer 17

The platysma muscle - muscle of facial expression

Question 18

Where nerve supplies the platysma muscles

Answer 18

cranial nerve VII (facial nerve)

Question 19

Where does the platysma muscle lie

Answer 19

It extends for the lower border of the mandible to the lower border of the neck

Question 20

Name the 4 fascial compartments of the neck

Answer 20

Prevertebral (deep) fascia
Investing (deep) fascia
The 2 carotid sheaths
Pretracheal (deep) fascia

Question 21

What deep fascia layer is the most superficial

Answer 21

Investing

Question 22

What is contained within the investing fascia

Answer 22

All other neck fascial compartments

encloses 2 pairs of muscles: trapezius and the sternocleidomastoid

Question 23

What fascia is deep to the investing fascia

Answer 23

Prevertebral fascia, the pre tracheal fascia and the 2 carotid sheaths

Question 24

What is contained within the prevertebral fascia

Answer 24

Encloses the cervical vertebrae and the postural neck muscles

Question 25

What is enclosed by the carotid sheaths

Answer 25

Internal jugular veins carotid arteries the vagus nerves the deep cervical lymph nodes

Question 26

What are the strap muscles responsible for

Answer 26

Depressing the laryngeal cartilage when speaking and swallowing

Question 27

What is the space between the prevertebral and the pre tracheal fascia called and why is this important

Answer 27

Retropharyngeal space - if infection develops, it will spread rapidly through this space

Question 28

where does the sternocleidomastoid attach

Answer 28

Sternal head - manubrium of the sternum clavicular head - medial end of the clavicle Both heads pass superiorly to attach to the mastoid process of the temporal bone

Question 29

Describe the anterior jugular vein

Answer 29

It is superficial vein in the superficial fascia which drains into he external jugular vein

Question 30

Describe the external jugular vein

Answer 30

A superficial vein in the superficial fascia which drains in to the subclavian vein

Question 31

what cranial nerve supplies the sternocleidomastoid and the trapezius

Answer 31

Cranial nerve XI - spinal accessory nerve

Question 32

Where does the carotid sheaths lie

Answer 32

Deep to the investing fascia and located anterolaterally in the neck either side of the thyroid gland

Question 33

Describe the structure of the carotid sheaths

Answer 33

Bilatera tubes of deep fascia which attach superiorly to the base of the skull. They run down the neck into the superior part of the thorax and the fascia will blend in with the mediastinal fascia

Question 34

What is enclosed within each carotid sheath

Answer 34

The internal jugular vein The common, then the internal carotid arteries The vagus nerve the deep cervical lymph nodes

Question 35

Where do both the left and right inferior thyroid arteries branch from

Answer 35

The subclavian artery

Question 36

Describe the venous drainage of the thyroid and parathyroid glands

Answer 36

Superior, middle and inferior

Question 37

What drains into the internal jugular vein

Answer 37

The superior and middle thyroid veins

Question 38

What drains into the left brachiocephalic vein

Answer 38

Both the right and left inferior veins

Question 39

Where is the location of the venous angle

Answer 39

Between the internal jugular vein and the subclavian vein

Question 40

Where do the paratracheal nodes sit

Answer 40

Either side of the trachea

Question 41

What 2 somatic branches does the vagus nerve give rise to in the larynx

Answer 41

Superior laryngeal nerve and the right recurrent laryngeal nerve

Question 42

Describe the route of the right recurrent laryngeal nerve

Answer 42

It is a branch of the vagus nerve that hooks up underrate the right subclavian artery to then ascend back up towards the larynx

Question 43

Describe the route of the right vagus nerve

Answer 43

Lateral aspect of the trachea - it then passes posteriorly to the root of the lung and follow onto the surface of the oesophagus

Question 44

Where does the phrenic nerve lie

Answer 44

Anteriorly to the root of the lung

Question 45

Describe the route of the vagus nerve on the left hand side

Answer 45

It follows the arch of the aorta and it gives off the left recurrent laryngeal nerve - it hooks underneath the arch of the aorta to ascend back up towards the larynx

Question 46

What are the names of the 4 strap muscles

Answer 46

Sternohyoid Thyrohyoid Omohyoid Sternothyroid

Question 47

What 1 of the 4 strap muscles has 2 bellies

Answer 47

The omohyoid - superior and inferior bellies

Question 48

What causes the omohyoid muscle to change direction

Answer 48

A small tendon that grips the mid portion of the muscle

Question 49

Where does the thyrohyoid muscle lie

Answer 49

The thyroid to the hyoid bone

Question 50

Where does the sternohyoid muscle lie

Answer 50

Sternum to the hyoid bone

Question 51

Where does the sternothroid muscle like

Answer 51

the sternum to the thyroid bone

Question 52

Where does the omohyoid muscle lie

Answer 52

Extends out towards the shoulder and attaches to the scapula to the hyoid bone

Question 53

What is the superior border of the manubrium

Answer 53

The jugular notch

Question 54

The external jugular vein cross what

Answer 54

The muscle belly of the sternocleidomastoid

Question 55

What forms the borders of anterior triangle of the neck

Answer 55

The laryngeal prominence of the thyroid cartilage, The jugular notch The sternal head border The angle of the mandible and the inferior border of the mandible

Question 56

What forms the borders of the posterior triangle of the neck

Answer 56

Trapezius | The clavicular head border of the sternocleidomastoid and the clavicle

Question 57

How is a classical thyroidectomy performed

Answer 57

An incision through the skin and platysma just above the jugular notch and superior to the clavicle along langers lines

Question 58

What 2 structures does the recurrent laryngeal nerve lie between

Answer 58

In a groove between the trachea and the oesophagus

Question 59

What happens if a recurrent laryngeal nerve is damaged

Answer 59

Results in hoarse voice or losing the voice altogether

Question 60

What happens if both recurrent laryngeals are damaged bilaterally

Answer 60

Aphonia (inability to produce sound and also the inability to close the rim glottidis to prevent aspiration or produce a good cough - very dangerous situation

Question 61

What does the right recurrent laryngeal nerve provide

Answer 61

Somatic motor supply to most of the skeletal muscles that move the right vocal cord