Question | Answer |
What is the largest endocrine gland in the body? | Thyroid |
Where is the thyroid located | front of the neck below the Adams's apple |
What shape is the thyroid have? | Butterfly |
What crucial role does the thyroid help set? | Metabolic rate |
The thyroid is a storehouse for what? | Iodine |
What is the normal variant of the thyroid? | Pyramidal lobe |
How does the thyroid gland develope? | As a tubular invagination in the floor of the primitive pharynx. |
An incomplete decent may lead to the formation of thyroid abnormally high in the neck called: | Lingual thyroid or aberrant thyroid |
Excessive desent of the thyroid leads to: | Substernal thyroid |
The thyroid is located | in the anterioinferior part of the neck |
The thryroid is located in a space outlined by | muscles, trachea, esophogus, carotid arteries and jugular veins |
The thyroid is made up of | Right and Left lobes |
The right and left lobes are connected by the | Isthmus draping over the trachea |
The superior border of the lobes begin at the | Thyroid cartilage |
The Right lobe is | often larger than the left |
Tall individuals | glands longitudinally elongated |
shorter individuals | glands more oval |
Normal dimensions of the lobes | vary widely |
The anteroposterior diameter | is the most reliable measurement of the thyroid. |
Four arteries supply blood | The upper poles receive blood via two superior thyroid arteries that arise from the ECA. The inferior thyroid artery is a branch of the thyrocervical trunk. ( a branch of the subclavian a.) |
What makes up the major neurovascular bundle? | Internal Jugular Vein, vagus nerve, CCA |
What makes up the minor neurovascular bundle? | inferior thyroid artery, recurrent laryngeal nerve mark the posterior border of the thyroid. |
Anatomic variants of the thyroid | pyramidal lobe 15-30% can arise from either lobe |
Hypothyroidism | Hashimoto's disease |
Hyperthyoidism | Graves' disease |
Hypothyroidism symptoms | dry brittle hair, angina, bradycardia, constipation, menorrhagia, dysmenorrhea, dry yellowish skin, cold intolerance, decreased sweating, lethargy, tiredness,fatigue, brittle nails |
Hyperthyroidism symptoms | hair-thinning, fine, Tachycardia, palpitations, diarrhea, amenorrhea, decreased menstrual flow, hot, flushed, moist skin, heat intolerance, increased sweating, nervousness, irritability, insominia, palmar erythema |
Goiter | refers to a diffuse enlargement of the thyroid gland |
Goiters are caused by | hypothyroid and hyperthyroid conditions |
goiters can become large and compress | the esophagus and trachea |
Posterolateral Landmarks of the thyroid | on transverse views the CCA and internal jugular vein form the posterior lateral border of the gland |
Posterolateral Landmarks of the thyroid | the artery is located medial to the vein |
Medial Landmark | The air-filled trachea forms the medial border and appears hyperechoic with posterior shadowing |
Anterolateral Landmark | The sternocleidomastoid is lateral and superficial to the omohyoid. The sternothyroid, sternohyoid and omohyoid muscles collectivley called the strap muscles form the anterolateral border of the gland. |
Strap Muscles | directly superficial to the thyroid gland is the sternothyroid muscle,which is bordered by the sternohyoid anteriorly and omohyoid laterally. |
Posterior Landmark | longus colli muscle appears as low-level, echogenic structure defining the posterior border of the gland |
Normal thyroid is uniformaly | echogenic, with medium-to high level echoes similiar to testes |
The strap muscles | are hypoechoic relative to the gland |
The LCM (longus colli muscle) | is triangulary shaped |
The esophagus is visualized slightly to the | left of mid-line adjacent to the trachea and appears and as circular hypoechoic structure. |
In the sagittal plane of imaging | the strap muscles and SCM (sternocleidomastoid muscle) are anterior to the gland. |
The strap muscles consist of | sternothyroid, sternohyoid and omohyoid muscles which form the anterolateral border of the gland |
What muscle is not a strap muscle? | the sternonocleidomastoid muscle which is located lateral and superficial to the omohyoid muscle. |
Myxedema | when hypothyroidism first appears in older children or adults |
Common symptoms of myxedema | lethargy, slow intellectual fx, fatigue, weakness, cold-intolerance, contipation, weight increase, hair loss, bradycardia. |
Cretinism (hypothyroidism) presents when? | during development and infancy |
Common symptoms of Cretinism | floppy infant, thick, protruding tongue, poor feeding, chocking episodes, thickened facial features, constipation, short stature, abnormal bone growth, mental retardation. |
Hyperthyroidism results from what? | over secretion of thyroid horomone |
Hyperthyroidism is predominantly found in whom? | adult women peak incidence between 30 and 50 yrs. |
Three causes collectively account for 99% of hyperthyroidism cases. | diffuse toxic hyperplasia(Graves'disease)-85% Toxic multinodudular goiter and toxic adenoma |
Hyperthyroidism is also called? | thyrotoxicosis |
It occurs as part of a syndrome which may include______________and _______________ and is know as Graves' disease | goiter and exopthalmos |
Causes of thyroid englargement | Inborn errors of throid hormone synthesis, nutritional iodine deficiency, goitrogenic substances, nontoxic nodular goiter, diffuse toxic goiter (graves' disease) throiditis (Hashimoto's ) and neoplasms (malignant or benign) |
Toxic goiter refers to a goiter with | hyperthyroidism |