This operation is based on careful dissection of various tissue planes between the muscles, vessels, and thyroid gland. Some type of self-retaining retractor is inserted to hold apart the skin flaps. In the presence of a large thyroid gland that necessitates division of sternohyoid and sternothyroid muscles, it is advisable to free the anterior margins of the sternocleidomastoid muscles. The margins of these muscles run diagonally across the outer limits of the wound and can be identified easily. The incision is made into the fascia along the margins of the sternocleidomastoid muscle (Figure 10). The handle of the scalpel is used as a dissecting tool to develop the correct plane of cleavage between the sternocleidomastoid muscle and the outer boundaries of the sternothyroid muscle (Figures 11 and 12).
To avoid bleeding, a vertical incision is placed exactly in the midline of the neck between the sternohyoid muscles, extending from the thyroid notch to the level of the sternal notch. All bleeding points are controlled by the application of hemostats. The tissues on either side of the incision are lifted up so that the incision is not carried directly through into the thyroid gland (Figure 13). The blunt handle of the knife is inserted beneath the exposed sternohyoid muscles (Figures 14 and 15). At this point the loose fascia over the thyroid gland should be picked up with forceps and incised with the scalpel in order to develop a cleavage plane between the thyroid gland and the sternothyroid muscle (Figures 16, 17, and 18). This is one of the most important steps in a thyroidectomy. Many difficulties may be encountered unless the proper cleavage plane is entered at this time. When the fascia of the sternothyroid muscle has been completely incised and reflected, the blood vessels in the capsule of the thyroid gland ...