Anatomy of the Thyroid Gland

Question 1

The thyroid gland is closely related to which anatomical structures in the anterior neck?

Answer 1

1. Larynx
2. Trachea

Question 2

Usually, the thyroid gland consists of which three parts?

Answer 2

1. Right lateral lobe
2. Left lateral lobe
3. Isthmus

Question 3

What is the isthmus of the thyroid gland?

Answer 3

The connection between the right and left lateral lobes

Question 4

The lateral lobes of the thyroid gland attach to what?

Answer 4

Lateral aspects of thyroid and cricoid cartilages

Question 5

The isthmus lies anterior to the ____ and ____ cartilages of the trachea

Answer 5

The isthmus lies anterior to the 2^nd and 3^rd cartilages of the trachea

Question 6

Where are the four parathyroid glands located?

Answer 6

Posterior surfaces of the thyroid gland’s lateral lobes

Question 7

What is one of the most common anatomical variations of the thyroid gland?

Answer 7

Pyramidal lobe

Question 8

Usually the pyramidal lobe originates from the _______ lateral lobe

Answer 8

Usually the pyramidal lobe originates from the left lateral lobe

Question 9

How does the thyroid gland begin its development?

Answer 9

A midline epithelial proliferation at the junction between the anaterior and posterior aspects of the tongue

Question 10

The thyroid gland will migrate inferiorly whist still being attached to the tongue via what?

Answer 10

Thyroglossal duct

Question 11

In which week of development will the thyroid gland reach its final postition?

Answer 11

7^th

Question 12

What are the platysma?

Answer 12

Broad sheet-like superficial muscles that overlap the sternocleidomastoid and sit in the subcutaneous tissue in the neck

Question 13

What is the nerve supply of the platysma muscles?

Answer 13

Facial nerve (CN VII)

Question 14

How many fascial compartments are there in the neck?

Answer 14

4

Question 15

What are the fascial compartments in the neck?

Answer 15

1. Prevertebral deep fascia
2. Investing deep fascia
3. Carotid sheaths
4. Pretracheal deep fascia

Question 16

What is the location of the prevertebral deep fascia?

Answer 16

Deep to the investing fascia

Located most posteriorly in the neck

Question 17

What is contained within the investing fascia?

Answer 17

1. All other neck fascial compartments
2. Trapezius
3. Sternocleidomastoid

Question 18

What is carried within the carotid sheaths in the neck?

Answer 18

1. Vagus nerves
2. Carotid arteries (common then internal)
3. Internal jugular veins
4. Deep cervical lymph nodes

Question 19

Where is the pretracheal fascia located and what does it enclose?

Answer 19

Most anteriorly within the enclosure of the investing fascia

Encloses:

1. Oesophagus
2. Trachea
3. Thyroid gland
4. Strap muscles
5. Recurrent laryngeal nerves

Question 20

Which nerve supplies the sternocleidomastoid and trapezius?

Answer 20

Spinal accessory nerve (CN XI)

Question 21

The external jugular vein runs within the __________ _______ and drains into the _____________ _____

Answer 21

The external jugular vein runs within the superficial fascia and drains into the subclavian vein

Question 22

Where does the anterior jugular vein run and where does it drain?

Answer 22

Superficial fascia

External jugular vein

Question 23

The sternocleidomastoid is enclosed within what?

Answer 23

Investing fascia

Question 24

The sternocleidomastoid has two heads, what are they and where do they both insert?

Answer 24

1. Sternal head - manubrium of the sternum
2. Clavicular head - medial end of the clavicle

Question 25

What is the origin of the sternocleidomastoid?

Answer 25

Mastoid process of the temporal bone

Question 26

The carotid sheaths are located _____________ either side of the __________ \_\_\_\_\_\_\_\_

Answer 26

The carotid sheaths are located **anterolaterally** either side of the **thyroid gland**

Question 27

Where do the carotid sheaths attach to the skull?

Answer 27

Base of skull (around jugular foramen and entrance to carotid canal)

Question 28

Where does the carotid sheath attach inferiorly?

Answer 28

Blends with mediastinal fascia

Question 29

Where is the vagus nerve located in the neck?

Answer 29

Carotid sheath (between the common carotid artery and the internal jugular vein)

Question 30

What is the arterial supply of the thyroid gland?

Answer 30

1. Superior thyroid arteries 2. Inferior thyroid arteries

Question 31

The inferior thyroid arteries are branches of which arteries?

Answer 31

Subclavian arteries

Question 32

The superior thyroid arteries are branches of which arteries?

Answer 32

External carotid arteries

Question 33

Which artery is an anatomical variant that may supply blood to the thyroid gland and where does it originate?

Answer 33

Thyroid ima artery Usually brachiocephalic

Question 34

What is the venous drainage of the thyroid gland?

Answer 34

Superior, middle and inferior thyroid veins

Question 35

Where do the superior and middle thyroid veins drain?

Answer 35

Internal jugular veins

Question 36

Where does the inferior thyroid vein drain?

Answer 36

Left brachiocephalic vein

Question 37

Where do the internal jugular veins drain?

Answer 37

Right and left brachiocepalic veins

Question 38

What is the lymphatic drainage of the thyroid gland a) Superiorly b) Inferiorly

Answer 38

a) Superior deep cervical lymph nodes b) Inferior deep cervical lymph nodes

Question 39

What are the types of lymph nodes surrounding the trachea?

Answer 39

1. Pretracheal 2. Paratracheal

Question 40

How is lymph returned to the circulation a) On the right side b) On the left side

Answer 40

a) Via right lymphatic duct to right venous angle b) Via thoracic duct to left venous angle

Question 41

The vagus nerves branch from the ________ \_\_\_\_\_\_\_\_\_ and exit the skull via the _________ \_\_\_\_\_\_\_\_\_\_ then descend within the ___________ \_\_\_\_\_\_\_\_\_

Answer 41

The vagus nerves branch from the **medulla oblongata** and exit the skull via the **jugular foramen** then descend within the **carotid sheaths**

Question 42

Within the chest the right vagus nerve will be found _______ to the trachea

Answer 42

Within the chest the right vagus nerve will be found **lateral** to the trachea

Question 43

Within the chest, the left vagus nerve will be found to which side of the aortic arch?

Answer 43

Left

Question 44

Both vagus nerve travel ________ to the lung hila

Answer 44

Both vagus nerve travel **posterior** to the lung hila

Question 45

Both vagus nerves pass into the abdomen with the \_\_\_\_\_\_\_\_\_\_\_

Answer 45

Both vagus nerves pass into the abdomen with the **oesophagus**

Question 46

The right recurrent larngeal nerve recurs under what?

Answer 46

Right subclavian artery

Question 47

The left recurrent laryngeal nerve recurs under what?

Answer 47

Arch of aorta

Question 48

What are the four strap muscles?

Answer 48

1. Sternohyoid 2. Sternothyroid 3. Thyrohyoid 4. Omohyoid

Question 49

How can the omohyoid muscle be distinguished?

Answer 49

1. Tendinous section within the middle segment 2. Fascial sling attaches it to clavcle preventing bowstringing

Question 50

If structures are damaged iatrogenically, what does this mean?

Answer 50

They are damaged by a clinician

Question 51

Recurent larngeal nerve injury results in what?

Answer 51

Paralysis of the vocal cords 1. Unilaterally - weakvoice and cough, hoarse voice 2. Bilaterally - aphonia (cannot make sound), inability to close rima glottidis, cannot produce good cough

Question 52

With bilateral recurrent laryngeal nerve injury, what is the risk of being unable to close the rima glottidis?

Answer 52

Cannot prevent aspiration