The term triangles of the neck is used to describe divisions created by major muscles in the neck region.

The side of the neck presents a somewhat quadrilateral outline, limited by:

• Above -  lower border of the body of the mandible, and an imaginary line extending from the angle of the mandible to the mastoid process;
• Below - upper border of the clavicle;
• In front - midline of the neck;
• Behind - anterior margin of the trapezius.

This space is subdivided into two large triangles by the sternocleidomastoid, which passes obliquely across the neck, from the sternum and clavicle below to the mastoid process of the temporal bone and the occipital bone above. 

The triangular space in front of the sternocleidomastoid muscle is called the anterior triangle of the neck; and the space behind it - the posterior triangle of the neck (also known as the lateral triangle of the neck).

• The anterior triangle is further divided into four triangles:
  • Carotid triangle
  • Muscular (omotracheal) triangle
  • Submandibular triangle
  • Submental triangle
• The posterior triangle may be subdivided into two triangles:
  • Occipital triangle 
  • Subclavian (omoclavicular) triangle