Which surgeon was awarded the Nobel Prize in Physiology or Medicine for his work on the "physiology, pathology, and surgery of the thyroid gland?"
The Nobel Prize in Physiology or Medicine was awarded to Emil Kocher in 1909. In addition to his research on the physiology of the thyroid, Kocher's operative methods greatly reduced the mortality risk of thyroidectomy. The Kocher clamp was designed to prevent hemorrhage from the hypervascular gland during thyroidectomy.
What congenital anomaly arises from the formation of the thyroid gland?
The medial thyroid anlage descends from the base of the tongue through a channel called the thyroglossal duct at week 3 to 4 of gestation. The duct normally closes after its descent, but may remain patent and is susceptible to secondary infection and dilatation, referred to as a thyroglossal duct cyst. Removal is accomplished with the Sistrunk operation which also removes the central portion of the hyoid bone.
The arterial supply of the thyroid arises from which of the following vessels?
The superior thyroid arteries arise from the external carotid arteries, and the inferior thyroid arteries arise from the thyrocervical trunk shortly after their origin from the subclavian arteries. A thyroid ima artery arises directly from the aorta or innominate artery in 1 to 4% of cases.
In what location, relative to the inferior thyroid artery (ITA), is the recurrent laryngeal nerve (RLN) found?
The RLN courses within the tracheoesophageal groove after emerging from the vagus nerve at the level of the aortic arch. As it ascends in the neck, the recurrent laryngeal nerve (RNL) may branch, and may pass anterior, posterior, or interdigitate with branches of the ITA. The location of the RLN must be confirmed before the ITA is divided.
Although injury to the RLN results in hoarseness (unilateral injury) or airway obstruction (bilateral injury), injury to the superior laryngeal nerve (SLN) results in a more subtle injury, affecting the ability to:
The external branch of the superior laryngeal nerve (SLN) lies on the inferior pharyngeal constrictor muscle and descends alongside the superior thyroid vessels before innervating the cricothyroid muscle. Therefore the superior pole vessels should not be ligated en masse, but should be individually divided low on the thyroid gland. Injury to the SLN leads to inability to tense the ipsilateral vocal cord, and impairs the ability to "hit high notes" while singing, or projecting the voice loudly.
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