Thyroid A&P

Question 1

what is the normal size of the thyroid gland in an adult in SAG?

Answer 1

SAG 4-5 cm

Question 2

what is the normal size of the thyroid gland in an adult in TRV?

Answer 2

TRV 1-2 cm

Question 3

what is the normal size of the thyroid in AP?

Answer 3

AP 1-2 cm

Question 4

what is the NL size of the isthmus in AP?

Answer 4

AP 2-6 mm

Question 5

what vessels run lateral to the thyroid (TRV)?

Answer 5

CCA & jugular vein

Question 6

what structure lies medial to the thyroid (TRV)?

Answer 6

trachea

Question 7

what muscles lie anterior to the trachea (TRV)?

Answer 7

strap muscles:
sternothyroid
sternohyoid
sternocleidomastoid

Question 8

what structures lie posterior to the trachea (TRV)?

Answer 8

longus colli muscle
minor neurovascular bundle

Question 9

what does the major neurovascular bundle consist of?

Answer 9

CCA
internal jugular vein
vagus nerve

Question 10

what does the minor neurovascular bundle consist of?

Answer 10

inferior thyroid artery
recurrent laryngeal nerve

Question 11

what structure lies to the left of midline posteromedial to left lobe?

Answer 11

esophagus

Question 12

how do you confirm you are imaging the esophagus vs. pathology?

Answer 12

ask patient to swallow. if it changes shape, it’s most likely esophagus.
also image in both planes.

Question 13

what are some functions of the thyroid gland?

Answer 13

1. endocrine gland – synthesizes, stores, secretes hormones
2. regulates cell metabolism

Question 14

what are 3 thyroid hormones?

Answer 14

1. thyroxine (T4)
2. triiodothyronine (T3)
3. calcitonin

Question 15

where are the superior parathyroid glands?

Answer 15

posterior to the upper poles of the thyroid

Question 16

where are the inferior parathyroid glands?

Answer 16

posterior to the inferior poles of the thyroid

Question 17

the parathyroid glands are lateral to the CCA. T/F?

Answer 17

false – they are medial

Question 18

where are the parathyroid glands compared to the longus colli muscle?

Answer 18

the parathyroid glands lie anterior to the longus colli muscle

Question 19

normal size of the parathyroid glands?

Answer 19

< 5 mm

Question 20

what hormone is secreted by the parathyroid gland and what does it do?

Answer 20

parathyroid hormone (PTH) regulates calcium levels in blood and bone

Question 21

a decrease in calcium may be a sign of parathyroid adenoma. T/F?

Answer 21

false. an INCREASE in calcium may be a sign of parathyroid adenoma

Question 22

what are 3 congenital variants of the thyroid & parathyroid?

Answer 22

1. pyramidal lobe
2. ectopic thyroid
3. ectopic parathyroid

Question 23

what is a pyramidal lobe?

Answer 23

a variant of the thyroid gland that looks like a finger-like extension of the isthmus

Question 24

which side does the pyramidal lobe usually extend from?

Answer 24

left side

Question 25

what is the percentage of the population that may have a pyramidal lobe?

Answer 25

15-30%

Question 26

what is the echogenicity of the pyramidal lobe compared to the thyroid gland?

Answer 26

isoechoic

Question 27

where is an ectopic thyroid most commonly found?

Answer 27

in the lingual location

Question 28

where is an ectopic parathyroid most commonly found?

Answer 28

axilla
mediastinum
more superior or inferior to original location

Question 29

a cold nodule of photon deficient area on nuclear medicine is an indication to get a thyroid US. T/F?

Answer 29

true

Question 30

other thyroid imaging modalities?

Answer 30

1. xray
2. ct
3. mri
4. nuclear medicine

Question 31

what do hot nodules in nuclear medicine mean for thyroid US?

Answer 31

hyperfunctioning thyroid absorbing large amounts of the isotope

Question 32

do hot nodules indicate benign or malignant tumors in the thyroid?

Answer 32

usually benign

Question 33

what do cold nodules in nuclear medicine mean for thyroid US?

Answer 33

hypofunctioning thyroid absorbing little or no isotope

Question 34

what are the chances a solitary cold nodule could indicate malignancy?

Answer 34

15-20%