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
Fascial spaces of the head and neck rare and are associated with marked trismus. The pterygomandibular space lies between the medial side of the ramus of the mandible and the lateral surface of the medial pterygoid muscle. The infra-temporal space is the inferior portion of the deep temporal space. Modern understanding of the fascial spaces of the head and neck developed from the landmark research of Grodinsky and Holyoke in the 1930s. They injected a dye into cadevers to simulate pus. Their hypothesis was that infection in the head and neck mainly spread by hydrostatic pressure. This is now accepted to be true for most infections in