Thyroid & Adrenal
Hyoid bone is closely associated with:
|C||Both of the above|
|D||None of the above|
a. The tissue bud that ultimately becomes the thyroid gland arises initially as a midline diverticulum in the floor of the pharynx.
b. This tissue originates in the primitive alimentary tract and consists of cells of endodermal origin.
c. The main portion of this cellular structure descends into the neck and develops into a bilobar solid organ.
d. The original attachment in the pharynx is in the buccal cavity at the foramen cecum. This structure becomes the thyroglossal duct, which is usually reabsorbed after 6 weeks of age. The very distal end of this remnant may occasionally be retained and mature as a pyramidal lobe in the adult thyroid.
e. Most thyroglossal duct cysts are found immediately beneath the hyoid bone and are noted in early childhood or infancy.
f. These cysts are almost always in the midline and can be found from the base of the tongue to the suprasternal notch.
g. They usually occur as a mass found in the midline on physical examination or when a localized infection occurs within that mass.
h. A chronically infected or draining thyroglossal duct cyst can lead to a chronic draining fistula.
i. For this reason, all thyroglossal duct cysts, on diagnosis, are treated surgically and excised because of their potential for infection.
j. The thyroglossal duct commonly passes through the center of the hyoid bone, thus requiring removal of the central portion of the structure.
k. Occasionally, papillary cancer can occur in the thyroid tissue within the thyroglossal duct cyst, and complete removal of the tract is required.