Question

What prevents upward expansion of a goiter causing downward expansion and thoracic structure compression, like the SVC?

A) Tracheal cartilage
B) Thyroid-stimulating hormone (TSH)
C) Sternocleidomastoid muscle
D) Ligaments and fibrous tissues

Answer 1

Ligaments and fibrous tissues prevent upward expansion of a goiter, not tracheal cartilage, TSH, or the sternocleidomastoid muscle.

Step-by-step explanation:

The upward expansion of a goiter is prevented by the presence of ligaments and fibrous tissues. These structures help to anchor the thyroid gland in place, preventing it from expanding upward and causing compression on thoracic structures like the superior vena cava (SVC). The tracheal cartilage, thyroid-stimulating hormone (TSH), and the sternocleidomastoid muscle do not play a direct role in preventing upward expansion of a goiter.