Thyroid and parathyroid

Question 1

What is the composition of the thyroid?

Answer 1

The thyroid is composed of two lateral lobes and a connecting portion called the isthmus.

Question 2

What type of gland is the thyroid?

Answer 2

The thyroid is an endocrine gland.

Question 3

True or False? The thyroid is highly vascular and demonstrates a lot of color Doppler fill.

Answer 3

False. The thyroid is highly vascular but does NOT demonstrate much color Doppler fill.

Question 4

Where is the isthmus located in relation to the trachea?

Answer 4

The isthmus is anterior to the trachea.

Question 5

Where is the trachea located in relation to the thyroid lobes?

Answer 5

The trachea is medial to the thyroid lobes.

Question 6

What is the position of the CCA, IJV, and vagus nerve in relation to the thyroid?

Answer 6

The CCA, IJV, and vagus nerve are posterolateral to the thyroid.

Question 7

What is the position of the strap muscles and sternocleidomastoid muscles in relation to the thyroid?

Answer 7

The strap muscles and sternocleidomastoid muscles are anterolateral to the thyroid.

Question 8

Where is the esophagus located in relation to the trachea?

Answer 8

The esophagus is posterior to the trachea.

Question 9

What are the strap muscles?

Answer 9

The strap muscles are sternohyoid, sternothyroid, and omohyoid.

Question 10

Which strap muscle is most anterolateral?

Answer 10

The sternohyoid is the most anterolateral strap muscle.

Question 11

Which strap muscle is closest to the thyroid?

Answer 11

The sternothyroid is closest to the thyroid.

Question 12

What muscle is located posterior to the thyroid?

Answer 12

The longus colli muscle is posterior to the thyroid.

Question 13

Where is the esophagus located in relation to the thyroid?

Answer 13

The esophagus is posterior to the thyroid.

Question 14

What is the blood supply of the thyroid?

Answer 14

The blood supply of the thyroid consists of superior and inferior thyroid arteries/veins and middle thyroid veins.

Question 15

What is the first branch of the external carotid artery?

Answer 15

The first branch of the external carotid artery is the superior thyroid artery.

Question 16

Which artery supplies the lower half of the thyroid?

Answer 16

The inferior thyroid artery supplies the lower half of the thyroid and is the largest branch of the thyrocervical trunk.

Question 17

What is the normal length of the thyroid lobes?

Answer 17

The thyroid lobes should be 4-6 cm in length.

Question 18

What is the normal measurement of the isthmus A/P?

Answer 18

The isthmus should be 2-6 mm A/P.

Question 19

What are the functions of the thyroid?

Answer 19

The functions of the thyroid are metabolism, growth, and development.

Question 20

True or False? Every cell in the body depends upon the thyroid hormones for regulation of their metabolism.

Answer 20

True.

Question 21

What labs are used for thyroid assessment?

Answer 21

The labs for thyroid include T3, T4, and TSH.

Question 22

What percentage of Triiodothyronine (T3) does the thyroid release?

Answer 22

The thyroid releases 10% of Triiodothyronine (T3).

Question 23

What percentage of Thyroxine (T4) does the thyroid release?

Answer 23

The thyroid releases 90% of Thyroxine (T4).

Question 24

What is calcitonin?

Answer 24

Calcitonin is a hormone produced by parafollicular cells of the thyroid gland that lowers blood calcium levels.

Question 25

What gland secretes TSH?

Answer 25

TSH is secreted by the pituitary gland.

Question 26

What regulates T3, T4, and TSH?

Answer 26

T3, T4, and TSH are regulated by the hypothalamus and pituitary gland.

Question 27

How should the thyroid appear on ultrasound?

Answer 27

The thyroid on ultrasound should appear homogeneous.

Question 28

How should the thyroid appear in relation to surrounding muscles and vasculature on ultrasound?

Answer 28

The thyroid on ultrasound should be hyperechoic to surrounding muscles and vasculature.

Question 29

What is a variant of the thyroid?

Answer 29

A variant of the thyroid is a pyramidal lobe, which 10-40% of the population have; an accessory lobe usually on the left.

Question 30

How many parathyroid glands do most people have?

Answer 30

Most people have 4 parathyroid glands.

Question 31

Where are the parathyroid glands located in relation to the thyroid gland?

Answer 31

The parathyroid glands are located posterior and lateral to the thyroid gland.

Question 32

Where are the parathyroid glands located in relation to the longus colli muscle?

Answer 32

The parathyroid glands are anterior to the longus colli muscle.

Question 33

What is the normal length of the parathyroid glands?

Answer 33

The parathyroid glands should be 5-7 mm in length.

Question 34

Where do the majority of parathyroid masses appear?

Answer 34

The majority of parathyroid masses appear in the area of an anatomic 'triangle' formed by the thyroid gland, longus colli muscle, CCA, and IJV.

Question 35

Which arteries supply the parathyroid glands?

Answer 35

The parathyroid glands are supplied by the superior and inferior thyroid arteries.

Question 36

Where does the venous drainage of the parathyroid go?

Answer 36

The venous drainage of the parathyroid is into the thyroid plexus of veins.

Question 37

What are the functions of the parathyroid glands?

Answer 37

The functions of the parathyroid glands are to secrete parathyroid hormone (PTH) and maintain homeostasis of blood calcium.

Question 38

What releases calcium from bone when calcium levels are low?

Answer 38

PTH releases calcium from bone when calcium levels are low.

Question 39

True or False? Parathyroids are seen in adults.

Answer 39

False. Parathyroids are normally not seen in adults unless they are abnormal; they may be seen in young patients.

Question 40

What are the indications for parathyroid ultrasound?

Answer 40

The indications for parathyroid ultrasound include hypercalcemia, which is when blood calcium levels are too high.

Question 41

What is the appearance of a parathyroid adenoma on ultrasound?

Answer 41

A parathyroid adenoma appears uniformly hypoechoic compared to the normal thyroid gland.