Thyroid and parathyroid Flashcards
What is the composition of the thyroid?
The thyroid is composed of two lateral lobes and a connecting portion called the isthmus.
What type of gland is the thyroid?
The thyroid is an endocrine gland.
True or False? The thyroid is highly vascular and demonstrates a lot of color Doppler fill.
False. The thyroid is highly vascular but does NOT demonstrate much color Doppler fill.
Where is the isthmus located in relation to the trachea?
The isthmus is anterior to the trachea.
Where is the trachea located in relation to the thyroid lobes?
The trachea is medial to the thyroid lobes.
What is the position of the CCA, IJV, and vagus nerve in relation to the thyroid?
The CCA, IJV, and vagus nerve are posterolateral to the thyroid.
What is the position of the strap muscles and sternocleidomastoid muscles in relation to the thyroid?
The strap muscles and sternocleidomastoid muscles are anterolateral to the thyroid.
Where is the esophagus located in relation to the trachea?
The esophagus is posterior to the trachea.
What are the strap muscles?
The strap muscles are sternohyoid, sternothyroid, and omohyoid.
Which strap muscle is most anterolateral?
The sternohyoid is the most anterolateral strap muscle.
Which strap muscle is closest to the thyroid?
The sternothyroid is closest to the thyroid.
What muscle is located posterior to the thyroid?
The longus colli muscle is posterior to the thyroid.
Where is the esophagus located in relation to the thyroid?
The esophagus is posterior to the thyroid.
What is the blood supply of the thyroid?
The blood supply of the thyroid consists of superior and inferior thyroid arteries/veins and middle thyroid veins.
What is the first branch of the external carotid artery?
The first branch of the external carotid artery is the superior thyroid artery.
Which artery supplies the lower half of the thyroid?
The inferior thyroid artery supplies the lower half of the thyroid and is the largest branch of the thyrocervical trunk.
What is the normal length of the thyroid lobes?
The thyroid lobes should be 4-6 cm in length.
What is the normal measurement of the isthmus A/P?
The isthmus should be 2-6 mm A/P.
What are the functions of the thyroid?
The functions of the thyroid are metabolism, growth, and development.
True or False? Every cell in the body depends upon the thyroid hormones for regulation of their metabolism.
True.
What labs are used for thyroid assessment?
The labs for thyroid include T3, T4, and TSH.
What percentage of Triiodothyronine (T3) does the thyroid release?
The thyroid releases 10% of Triiodothyronine (T3).
What percentage of Thyroxine (T4) does the thyroid release?
The thyroid releases 90% of Thyroxine (T4).
What is calcitonin?
Calcitonin is a hormone produced by parafollicular cells of the thyroid gland that lowers blood calcium levels.
What gland secretes TSH?
TSH is secreted by the pituitary gland.
What regulates T3, T4, and TSH?
T3, T4, and TSH are regulated by the hypothalamus and pituitary gland.
How should the thyroid appear on ultrasound?
The thyroid on ultrasound should appear homogeneous.
How should the thyroid appear in relation to surrounding muscles and vasculature on ultrasound?
The thyroid on ultrasound should be hyperechoic to surrounding muscles and vasculature.
What is a variant of the thyroid?
A variant of the thyroid is a pyramidal lobe, which 10-40% of the population have; an accessory lobe usually on the left.
How many parathyroid glands do most people have?
Most people have 4 parathyroid glands.
Where are the parathyroid glands located in relation to the thyroid gland?
The parathyroid glands are located posterior and lateral to the thyroid gland.
Where are the parathyroid glands located in relation to the longus colli muscle?
The parathyroid glands are anterior to the longus colli muscle.
What is the normal length of the parathyroid glands?
The parathyroid glands should be 5-7 mm in length.
Where do the majority of parathyroid masses appear?
The majority of parathyroid masses appear in the area of an anatomic ‘triangle’ formed by the thyroid gland, longus colli muscle, CCA, and IJV.
Which arteries supply the parathyroid glands?
The parathyroid glands are supplied by the superior and inferior thyroid arteries.
Where does the venous drainage of the parathyroid go?
The venous drainage of the parathyroid is into the thyroid plexus of veins.
What are the functions of the parathyroid glands?
The functions of the parathyroid glands are to secrete parathyroid hormone (PTH) and maintain homeostasis of blood calcium.
What releases calcium from bone when calcium levels are low?
PTH releases calcium from bone when calcium levels are low.
True or False? Parathyroids are seen in adults.
False. Parathyroids are normally not seen in adults unless they are abnormal; they may be seen in young patients.
What are the indications for parathyroid ultrasound?
The indications for parathyroid ultrasound include hypercalcemia, which is when blood calcium levels are too high.
What is the appearance of a parathyroid adenoma on ultrasound?
A parathyroid adenoma appears uniformly hypoechoic compared to the normal thyroid gland.
