For descriptive and clinical purposes, the neck is divided into the anterior and posterior triangles. These triangles are defined by the sternocleidomastoid (structure 1) and the trapezius muscle.
Anterior triangle:
- Bounded by -
- Structure 2: Anterior border of the sternocleidomastoid, which is the lateral boundary
- Structure 3: Inferior border of mandible, which is the superior boundary
- Structure 4: Midline of the neck, which is medial boundary
Posterior triangle:
- Bounded by -
- Structure 5: Posterior border of the sternocleidomastoid, which is the anterior boundary
- Structure 6: Position of the clavicle, which is the inferior boundary
- Anterior border of trapezius makes up the posterior boundary