Thyroid Gland Flashcards Preview

ESA 4 - Head and Neck > Thyroid Gland > Flashcards

Flashcards in Thyroid Gland Deck (38):
1

What is the thyroid gland? 

An endocrine structure

2

Where is the thyroid gland located? 

In the anterior neck, spanning between C5 and T1 vertebrae

3

What is the thyroid gland divided into? 

Two lobes

4

What connects the two lobes of the thyroid gland? 

An isthmus 

5

Where does the thyroid gland lie in the neck?

  • Behind the sternohyoid and sternothyroid muscles
  • Wraps around the criocoid cartilage and superior tracheal rings
  • Inferior to thryoid cartilage of larynx

 

6

What compartment of the neck is the thyroid gland in? 

Visceral compartment

7

Other than the thyroid gland, what else is in the visceral compartment of the neck? 

  • Traachea
  • Oesophagus
  • Pharynx

 

8

What is the visceral compartment of the neck bound by? 

Pretracheal fascia

9

Where does the thyroid gland form during development? 

In the floor of the primitive pharynx, near the base of the tongue 

10

What happens to the thyroid gland during development? 

It descends down the neck to lie in its adult anatomical position 

11

What does the thyroid gland move through during developmental descent? 

A duct called the thyroglossal duct

12

What normally happens to the thyroglossal duct? 

It fuses and regresses in the adult 

13

What may happen if the thyroglossal duct does not regress? 

  • Continuation as pyramidal lobe
  • Persist as thryoglossal cysts

 

14

What portion of the thryoglossal duct continues as a pyramidal lobe? 

Distal portion 

15

In what % of individuals does the distal portion of the thyroglossal duct continue as a pyramidal lobe? 

50%

16

Effectively, what is the pyramidal lobe? 

An extra piece of thyroid tissue 

17

What are the clinical consequences of the thyroglossal duct continuing as a pyramidal lobe? 

There are none 

18

How may thyroglossal cysts present? 

As a mass in the midline of the neck, and can be excised surgically 

19

Why does the thyroid gland need to be highly vascularised? 

Because it secretes hormones directly into the blood 

20

How is blood supply to the thyroid gland achieved? 

Two main arteries; superior and inferior thyroid arteries 

21

Where does the superior thyroid artery arise from? 

External carotid artery, it is the first branch 

22

What course does the superior thyroid artery take after arising? 

Descends towards the thyroid gland 

23

What does the superior thyroid artery supply? 

Superior and anterior portions of the gland

24

Where does the inferior thyroid artery arise from? 

The thyrocervical trunk 

25

What is the thyrocervical trunk a branch of? 

The subclavian arter y

26

What course does the inferior thyroid artery take? 

Travels superomedially to reach the inferior pole of the thyroid

27

What does the inferior thyroid artery supply? 

The postero-inferior aspect

28

What artery supplying the thyroid gland is present in some people? 

The thyroid ima artery 

29

What % of people is the thyroid ima artery present in? 

The brachiocephalic trunk of the arch of the aorta

30

What does the thryroid ima artery supply? 

The anterior surface and isthmus 

31

What is the venous drainage of the thyroid gland? 

  • Superior thyroid
  • Middle thyroid
  • Inferior thyroid

 

32

What do the superior and middle thyroid veins drain into? 

The internal jugular veins 

33

Where does the inferior thyroid vein drain into? 

The brachiocephalic vein

34

What is the innervation of the thyroid gland? 

Branches derived from the sympathetic trunk

35

What regulates the release of hormones from the thyroid gland? 

Pituitary gland 

36

Where do the left and right recurrent laryngeal nerves arise from? 

Their respective vagus nerves

37

What course to the recurrent laryngeal nerves take? 

The descend into the chest, and then hook around the subclavian artery (right) or arch of aorta (left). The nerve then ascends back up the neck, running between the trachea and oesophagus. They pass under the thyroid gland to innervate the thyroid 

38

What is the clinical relevance of the close proximity between the thyroid gland and recurrent laryngeal nerves? 

During surgety on the thyroid gland, care must be taken not to ligate or damage the recurrent laryngeal nerves