Anterior triangle

The anterior triangle forms the anterior compartment of the neck and is separated from the posterior triangle by the sternocleidomastoid muscle. The triangles of the neck are surgically focused, first described from early dissection-based anatomical studies which predated cross-sectional anatomical description based on imaging (see deep spaces of the neck)..

Gross anatomy

The anterior triangle is an inverted triangle with its base above and the apex pointing downwards at the manubrium of the sternum. It can be further subdivided into smaller triangles by the crossing of digastric and omohyoid muscles.

Contents

The anterior triangle is subdivided into 3 paired triangles and a single midline triangle:

Paired triangles:

• digastric triangle
• muscular triangle
• carotid triangle

Single midline triangle:

• submental triangle

Boundaries

• anterior: median line of the neck
• posterior: anterior margin of sternocleidomastoid
• base: inferior border of the mandible

Related pathology

Determining the nature or origin of masses in the anterior triangle is difficult clinically. Radiological investigations are paramount in defining the origin and the extent of these masses. Head and neck tumors often metastasize to lymph nodes in the neck. A significant proportion of patients with head and neck malignancy have lymph node metastasis in the neck on presentation. Therefore understanding the anatomical position of lymph nodes in the neck help to stage the disease and aids in the planning of surgical management.