Hypothyroidism: Overview, Causes, and Symptoms>Hypothyroidism. When your thyroid gland comes under attack from malfunctioning immune cells, it impairs your thyroid's ability to make thyroid hormone. This can result in hypothyroidism. Hashimoto's thyroiditis is the most common cause of hypothyroidism. If Hashimoto's thyroiditis attacks your thyroid to the point that the gland can no longer produce enough thyroid hormones for your body to function properly, then you will develop hypothyroidism.
A ligament is the tissue that connects two bones to form a joint. It's tough and fibrous, which means that when it tears, a ligament can take quite a while to heal and might even require surgery. Ligament comes from the Latin ligare meaning to bind, tie, which is precisely what a ligament does. Ligaments only connect bones to bones. Ligaments allow for range of motion. Think of how your knee or elbow is able to move up and down like a hinge. That's thanks to the ligaments connecting the bones to form knee and elbow joints.
Medical Definition of ligamentum arteriosum. : a cord of tissue that connects the pulmonary trunk and the aorta and that is the vestige of the ductus arteriosus.