DMU Thyroid Chapt 18

• trilodothyronine (T3)
• thyroxine (T4)
• calcitonin

• normally 2, a left and right connected by the isthmus.
• sometimes a pyramidal lobe that arises from the isthmus and tapers superiorly

• adult:
• 40-60mm long
• 20-30 mm AP
• 15-20mm wide

• Children:
• 20-30mm long
• 12-15mm AP
• 10-15mm wide

Anterior - strap muscles (sternothyroid, omohyoid, sternohyoid, and sternocleidomastoid)

Posterior - carotid sheath (common carotid artery, internal jugular vein, and vagus nerve), longus coli muscle (posterior and lateral)

Medial - larynx, trachea, inferior constrictor of the pharynx, and esophagus

Medial -

normal thyroid has a fine homogeneous echotexture that is more echogenic than the surrounding muscle structure

ultrasound is used to define the anatomic structures within and surrounding the thyroid gland rather than to determine the physiology of the gland

anechoic areas, echogenic fluid, or moving fluid levels

goiter

highly variable. any size, single or multiple, and can appear as a solid, partially cystic, or largely cystic mass

usually hypoechoic relative to normal thyroid

peripheral halo

flat and disc shaped

less than 4mm

on the posterior medial surface of the thyroid gland.

most people have 4 glands

two lie posterior to each superior pole of the thyroid and the other two lie posterior to the inferior pole

neoplasm

iodine deficiency

papillary carcinoma

congenital anomalies that appear in the midline of the neck anterior to the trachea

cystic formations usually located lateral to the thyroid gland

Graves disease

rapidly growing mass in the neck area

nonvascular hypoechoic and lobulated mass

smooth homogeneous hypoechoic cortex and echogenic fatty internal hilum

• adenoma
• primary hyperplasia
• rarely - carcinoma located in the parathyroid gland