The anterior belly of the omohyoid muscle is divided from the sling of the digastric muscles; the dissection can then be completed after the posterior belly of the digastric muscle is exposed (Figure 17). Retraction of the posterior belly of the digastric superiorly exposes the internal jugular vein for clamping and division (Figure 18). Retraction of the posterior belly of the digastric muscle also allows complete exposure of the hypoglossal nerve (Figure 18). The internal jugular vein must be clamped high, since the upper limit of the internal jugular chain of lymphatics is one of the most common areas for metastatic cancer in the neck. To ensure that it has been divided high, the tail of the parotid (Figure 19) is sacrificed as the complete surgical specimen is excised. If extensive node involvement is present in the upper jugular chain of lymphatics, additional exposure can be obtained by total division of the posterior belly and its subsequent total removal. The dissection is completed with the division of the sternocleidomastoid muscle at the mastoid process.