From the Research
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. This surgical procedure involves the removal of lymph nodes and surrounding tissues in the neck, including the internal jugular vein, sternomastoid muscle, spinal accessory nerve, and submandibular salivary gland. The posterior belly of the digastric muscle is typically spared because it is not directly involved in the lymphatic drainage pathways that are the primary targets of the procedure, and preserving it helps maintain some functional anatomy in the neck region, as noted in a study published in 1. Radical neck dissection is most commonly performed for advanced head and neck cancers, though modified versions that preserve additional structures are now more frequently used to reduce morbidity while maintaining oncological effectiveness, as discussed in 2 and 3. It's worth noting that anatomical variations, such as those described in 1 and 4, can impact the procedure and that surgeons should be aware of these variations to ensure thorough dissection and avoid complications. Additionally, the choice of incision and clearance of the posterior belly of the digastric muscle are important considerations, as highlighted in 5. Overall, preserving the posterior belly of the digastric muscle is a key aspect of radical neck dissection, and its preservation helps to maintain functional anatomy and reduce morbidity, as supported by the most recent and highest quality studies, including 1 and 4.