The term triangles of the neck is used to describe several topographical regions found within the neck that have triangular-shaped appearances. These triangles are bounded mostly by various major neck muscles. 

They are important structures, as they contain various nerves, blood vessels, lymph nodes and glands. Also, they serve as neck surface landmarks for clinicians, as these triangles and their contents can be easily identified during palpation.

Overall, each side of the neck is limited by the following structures:

• Superior - inferior border of the body of the mandible, an imaginary line extending from the angle of the mandible to the mastoid process of the temporal bone, superior nuchal line of the occipital bone to the external occipital protuberance;
• Inferior - superior border of the clavicle;
• Anterior - midline of the neck;
• Posterior - anterior margin of the trapezius.

Each neck side can be further subdivided into two major neck triangles by the sternocleidomastoid. It passes obliquely across the neck, stretching from the sternum (Read more!) and clavicle below to the mastoid process of the temporal bone and superior nuchal line of the occipital bone above. Each major triangle can be further subdivided into even smaller triangles.

The triangular space anterior to the sternocleidomastoid is called the anterior neck triangle (Read more!), and it contains the following smaller triangles:

• Carotid triangle (Read more!)
• Muscular (omotracheal) triangle (Read more!)
• Submandibular triangle (Read more!)
• Submental triangle (Read more!)

In contrast, the space behind the sternocleidomastoid is the posterior or lateral neck triangle (Read more!). It is composed of the following two minor triangles:

• Occipital triangle (Read more!)
• Subclavian (omoclavicular) triangle (Read more!)