What are the main gross features of the thyroid?
Pyramidal lobe (50% of population)
Describe the arterial supply to the thyroid.
1. Superior thyroid artery (first branch of the external carotid artery)
2. Inferior thyroid artery (branch of the thyrocervical trunk)
3. (IMA 1 artery rare)
Describe the venous supply to the thyroid.
1. Superior thyroid vein
2. Middle thyroid vein
3. Inferior thyroid vein
What percentage of patients have a pyramidal thyroid lobe?
What veins do you first see after opening the platysma muscle when performing a thyroidectomy?
Anterior jugular veins
Name the lymph node group around the pyramidal thyroid lobe.
Delphian lymph node group
Which ligament connects the thyroid to the trachea?
The ligament of Berry
What is the thyroid IMA (not I.M.A.) artery?
How many patients have one?
Small inferior artery to the thyroid from the aorta or innominate artery;
Name the most posterior extension of the lateral thyroid lobes.
Tubercle of Zuckerkandl
Which paired nerves must be carefully identified during a thyroidectomy?
Recurrent laryngeal nerves, which are found in the tracheoesophageal grooves and dive behind the cricothyroid muscle; damage to these nerves paralyzes laryngeal abductors and causes hoarseness if unilateral, and airway obstruction if bilateral
The recurrent laryngeal nerves are found in the _____________ grooves and dive behind the __________ muscle.
The recurrent laryngeal nerves are found in the tracheoesophageal grooves and dive behind the cricothyroid muscle.
Damage to the recurrent laryngeal nerves paralyzes laryngeal ___ductors and causes __________ if unilateral, and __________ if bilateral.
Damage to the recurrent laryngeal nerves paralyzes laryngeal abductors and causes hoarseness if unilateral, and airway obstruction if bilateral
Following thyroidectomy, a patient presents with a deeper and quieter voice (unable to hit high pitches).
Damage to the superior laryngeal nerve
What is the most common site of conversion of T4 to T3?
Peripheral (e.g., the liver)
What is the half-life of Synthroid® (levothyroxine)?
What do parafollicular cells secrete?
What is the most common cause of thyroid enlargement?
What percentage of cold thyroid nodules are malignant?
Name the FIVE main types of thyroid carcinoma and their relative percentages.
1. Papillary carcinoma: 80% (Popular Papillary)
2. Follicular carcinoma: 10%
3. Medullary carcinoma: 5%
4. Hürthle cell carcinoma: 4%
5. Anaplastic/undifferentiated carcinoma: 1% to 2%
Most individuals with thyroid carcinoma are ____thyroid.
Most individuals with thyroid carcinoma are euthyroid.