Plate 191

This dissection consists of turning up the areolar and lymphoid tissues of the neck lying along the course of the internal jugular vein, which is reflected upward with these structures (Figure 12). All loose areolar tissue about the carotid artery is completely removed. This dissection may be carried out without danger to any of the vital structures, since both the vagus nerve and the common carotid artery are in full view and the other important nerve structures—namely, the phrenic nerve and the brachial plexus—are covered by the prevertebral fascia (Figure 12). As the dissection proceeds superiorly, branches of the cervical plexus are seen penetrating the fascia; they should be divided as they emerge through the fascia.

In the anterior part of this phase of the dissection, tributaries of the superior thyroid, superior laryngeal, and pharyngeal veins are seen as they cross the operative field to enter the jugular vein. These may be ligated as the dissection proceeds. The carotid bifurcation can usually be identified by the appearance of the superior thyroid artery (Figure 12). With reasonable care this vessel can be preserved. After exposure of the bifurcation, dissection proceeds superiorly with some caution to expose the hypoglossal nerve as it crosses both the internal and external carotid arteries 1 cm or so above the carotid bifurcation (Figure 12). The surgeon should watch for this nerve as it emerges deep to the posterior belly of the digastric muscle. The hypoglossal nerve continues forward into the submaxillary triangle, where it lies inferior to the main submaxillary salivary duct.

After identification of the hypoglossal nerve, attention should be directed to the submental area of the neck. The fascia from the midline of the neck is divided (Figure 13). This facilitates exposure of the anterior belly of the digastric muscle and the underlying mylohyoid muscle. Complete exposure of the digastric muscle in the submental compartment is necessary to remove the paired submental nodes (Figure 13 or 14). By following the anterior digastric muscle from anterior to posterior, the submaxillary gland is exposed. The submaxillary gland is dissected from its bed by approaching the gland anteriorly (Figure 15). By mobilizing the gland from its bed from anterior to posterior, the lingual nerve, which lies in the most superior aspect of the submaxillary space, the submaxillary duct, which lies in the midportion of the compartment, and the hypoglossal nerve, which lies in the most inferior aspect of the area, are identified (Figure 16). This exposure may be eased by traction on the submaxillary gland with a tenaculum. This allows the surgeon to visualize the posterior edge of the mylohyoid muscle and to retract this muscle anteriorly (Figure 16), thereby exposing the three important structures: the lingual nerve, the salivary duct, and the hypoglossal nerve. To facilitate removal of the submaxillary gland, the major salivary duct is divided and ligated.

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