From the Guidelines
The answer is (e) posterior belly of the digastric muscle. In a radical neck dissection, the posterior belly of the digastric muscle is preserved while the other structures listed are removed. Radical neck dissection is an extensive surgical procedure typically performed to remove lymph nodes and surrounding tissues in cases of head and neck cancer. This procedure involves the removal of all five lymph node groups in the neck along with several non-lymphatic structures including the internal jugular vein, sternomastoid muscle, spinal accessory nerve, and submandibular salivary gland. The posterior belly of the digastric muscle is typically preserved because it serves as an important anatomical landmark during surgery and maintains some functional aspects of the neck. According to the study published in the Journal of the National Comprehensive Cancer Network 1, the less-radical procedures preserve the sternocleidomastoid muscle, jugular vein, spinal accessory nerve, or selective lymph node levels, but in a classic radical neck dissection, these structures are removed. Key points to consider in radical neck dissection include:
- Removal of the internal jugular vein
- Removal of the sternomastoid muscle
- Removal of the spinal accessory nerve
- Removal of the submandibular salivary gland
- Preservation of the posterior belly of the digastric muscle This muscle helps with jaw movement and swallowing, and its preservation can contribute to better post-operative function. Modern approaches to neck dissection have evolved to be more selective and modified to preserve certain structures when oncologically safe, but in a classic radical neck dissection, the posterior belly of the digastric muscle remains intact, as noted in the study 1.