Posterior triangle of the neck which divides the space into two triangles: A) Nerves and plexuses: B) Vessels: C) Lymph nodes: D) Muscles: The accessory nerve (CN XI) is particularly vulnerable to damage during lymph node biopsy. Damage results in an inability to shrug the shoulders or raise the arm above the head, particularly due to compromised trapezius muscle innervation. The Internal jugular vein's superficial location within the posterior triangle also makes it vulnerable to injury. Posterior triangle of the neck The posterior triangle (or lateral cervical region) is a region of the neck. It has the following boundaries: Apex: Union of the sternocleidomastoid and
American Academy of Otolaryngology–Head and Neck Surgery before adding "Head and Neck Surgery" to its name, yielding the American Academy of Otolaryngology–Head and Neck Surgery in 1980. In 1981, the American Council of Otolaryngology (ACO), which had formed in the 1960s for purposes outside the scope of the original educational organization (such as lobbying), merged with the American Academy of Otolaryngology–Head and Neck Surgery. American Academy of Otolaryngology–Head and Neck Surgery The American Academy of Otolaryngology–Head and Neck Surgery (AAO-HNS) is one of the largest of the world's many professional associations for medical specialists, with nearly 12,000 specialists in the area of otolaryngology (otorhinolaryngology) - caring for