Level Ia
Ia
Definition
Level I nodes lie above the hyoid bone, below the mylohyoid muscle, and anterior to a transverse line drawn on each axial image tangent to the posterior surface of the submandibular gland on each side of the neck
- IA (Submental nodes) lie between the medial margins of the anterior bellies of the digastric muscles
- IB (Submandibular nodes) lie on each side lateral to the level IA nodes and anterior to the back of each submandibular gland.
References
Robbins KT, Shaha AR, Medina JE, et al. Consensus statement on the classification and terminology of neck dissection. Arch Otolaryngol Head Neck Surg. 2008 May. 134(5):536-8.
