Dissection Of The Strap Muscles

Although this is described as the last step of the operation, it may be performed in a different order according to the needs of the surgery and the location of the primary tumor.

The midline constitutes the medial border of the dissection for unilateral operations. Thus, a midline cut is made in the superficial layer of the cervical fascia from the upper border of the surgical field to the sternal notch (Fig. 4-52). If the upper end of the anterior jugular vein was not transected at a previous step of the operation, it is now identified, ligated, and divided. The same is made at the lower boundary of the dissection. After both ends of the anterior jugular vein have been ligated and divided, the fascia is dissected from the underlying strap muscles. The dissection starts at the upper part of the surgical field and continues in a lateral and inferior direction. The sternohyoid and omohyoid muscles are completely freed from their fascial covering (Fig. 4-53).

As the dissection proceeds laterally toward the carotid sheath the superior thyroid artery can be identified coursing in an inferomedial direction toward the thyroid gland (Fig. 4-54). Depending on the resection of the primary tumor, the superior thyroid artery can be preserved or should be ligated and divided. The common facial vein and a variable vein communicating the superficial

Figure 4-51 After dissection of the carotid sheath the specimen remains pedicled over the strap muscles (right side). IJ, internal jugular vein; cb, carotid bifurcation; hn, hypoglossal nerve; ac, ansa cervicalis (superior root); dm, digastric muscle; oh, omohyoid muscle; S, specimen.

Figure 4-52 Midline incision for the dissection of the fascia over the strap muscles.

Figure 4-53 Dissection of the strap muscles on the right side. sh, sternohyoid muscle; oh, omohyoid muscle; SG, submandibular gland; aj, anterior jugular vein; FS, fascia of the strap muscles.

and deep venous systems of the neck (Kocher's vein) are usually ligated and divided before the specimen is completely released from the strap muscles.

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