Welcome to this presentation on the neck part II. During this presentation, we’re going to cover
three subject areas. We’re going to begin by looking at the thyroid gland. Secondly, we'll visit
the stellate ganglion. Then lastly, we’ll visit the thoracic outlet. As we move through
each of these three topical areas, we’ll discuss clinical correlations. So here we begin with
the thyroid. What I want you to understand here at the beginning is some really basic anatomy.
First, the thyroid is made up of lobes. Here, we see the right lobe. Next, we have the left lobe.
Lastly, both lobes are connected by an isthmus. This particular slide shows a very important
clinical relationship or anatomic relationship. This is the relationship of the thyroid gland
to the recurrent laryngeal nerves. Each laryngeal nerve here is the right recurrent laryngeal nerve.
It’s lying within the tracheoesophageal groove. We see that groove between the trachea
and the esophagus which lies posteriorly. We also see the same relationship. However,
it’s unlabelled on the opposite side. So here is your left recurrent laryngeal nerve. Again,
it travels in the tracheoesophageal groove on that particular slide. Clinically, these are important
during a thyroidectomy. The surgeon has to carefully identify these nerves and preserve them
so they are not injured during the removal of the thyroid gland. We’ll also demonstrate another
clinical correlation of the recurrence when we talk about thyroid goiter. Here are some
important aspects about the recurrent laryngeal nerves. Both recurrent laryngeal nerves are
branches of the vagus nerve. They will supply all the intrinsic laryngeal muscles with the exception
of the cricothyroid. They are called recurrent as they come off the vagus nerve and then
travel back upwards to either side of the trachea and ultimately, to their destination
of the larynx. The left and right recurrent laryngeal nerves do have some anatomic
relationship. The difference is the left recurrent laryngeal nerve loops around the aortic arch
in the vicinity of the ligamentum arteriosum, whereas the right recurrent laryngeal nerve loops
more superiorly on the right side and loops under the right subclavian artery. Here is an important
clinical correlation. Here we’re looking at goiter. This particular individual has a very enlarged
thyroid gland, very large mass that’s very visible. In this particular individual, there are multiple
enlarged nodules. So this particular form of goiter is multinodular. Some of the symptoms
that are associated with a goiter are as follows: one is coughing. This has a mass effect
on the respiratory passageways and the larynx. Second symptom is hoarseness. Very large
goiters can involve the recurrent laryngeal nerves and if they become involved, then they’re
unable to effectively activate the muscles of the larynx and can then create the hoarseness.
Another symptom that can be associated with goiter is a difficulty swallowing, dysphagia.
This would be due to a mass effect, so the mass is compressing the structures that convey
the bolus of food. Then lastly, again due to a mass effect, you can have compression of your
respiratory passageways in the area of the trachea and making that a problem for some patients.
A very common procedure to demonstrate whether or not nodules are functional nodules
or non-functional nodules is to utilize technetium-99m pertechnetate scan. We see here
in the image the results of such a scan. Hot nodules are going to show up in this kind of
coloration that we see here. This is due to the presence of functional thyroid nodules.
They’re taking up the technetium-99m. So these areas light up when you have a hot nodule
region. A cold nodule is not a functional nodule so these types of nodules will not pick up
the technetium. This area here represents a cold nodule in the scan. So here, we are
demonstrating more specifically some of the aspects of a cold nodule. Again, it’s this area
here, non-functional. These are usually benign. Then lastly, the odds of being malignant
are going to be greater than the hot nodules. Here we’re looking at the thyroid gland
with respect to a clinical procedure, its removal, a thyroidectomy. Some of the indications
for a thyroidectomy are what we just went through, for example a goiter. Cancer of the thyroid
gland would also be another indication for its removal and then lastly, persistent
hyperthyroidism. Some complications associated with a thyroidectomy include bleeding
from the vasculature, either arterial bleeding or venous bleeding. Infection is always a concern
in any surgical procedure. As we discussed not too long ago, hoarseness of the voice can occur
if there’s surgical injury to one of the recurrent laryngeal nerves. So again, it’s very important
to isolate them and protect them during a thyroidectomy. The last complication to highlight
for your information is that some patients can have hypoparathyroidism. This is due to not being
able to adequately identify the parathyroid glands before the removal of the thyroid.
As a result, the parathyroids are also removed. Then you do not have enough functional
parathyroid tissue remaining for them to carry out their function.