Anatomical Triangles of the Neck

Anatomical Triangles of the Neck

• The neck is subdivided into several anatomical triangles, crucial for identifying and locating key structures. These triangles are defined by muscles, offering a framework for understanding regional anatomy.

• Anterior Triangle: Bounded by the midline, the mandible, and the sternocleidomastoid muscle. It's further subdivided into smaller triangles, each containing specific important structures.

  • Submandibular Triangle: Located inferior to the mandible, bordered by the anterior belly of the digastric muscle, the inferior belly of the digastric muscle, and the sternocleidomastoid muscle. Contains the submandibular gland, part of the facial artery and vein, and other related lymphatic structures.
  • Carotid Triangle: Defined by the sternocleidomastoid muscle, the superior belly of the omohyoid muscle, and the posterior belly of the digastric muscle. Contains the carotid artery, internal jugular vein, vagus nerve, and deep cervical lymph nodes. This triangle is vital for understanding important vascular and neurological pathways in the neck.
  • Submental Triangle: The smallest triangle in the anterior triangle. It's located anterior to the hyoid bone, bordered by the anterior bellies of the digastric muscles and the midline. Contains a small amount of subcutaneous tissue, and some important lymphatic nodes.
  • Muscular Triangle: Bounded by the superior belly of the omohyoid muscle, the sternocleidomastoid muscle, and the midline. Containing the infrahyoid muscles, this area is important for understanding the relationship and mobility of the larynx and hyoid. It gives access to the infrahyoid muscles and part of the thyroid gland.

• Posterior Triangle: Located posterior to the sternocleidomastoid muscle and anterior to the trapezius muscle. It's bordered by the clavicle, the sternocleidomastoid muscle, and the superior part of the omohyoid muscle. Contains important structures associated with the brachial plexus and the accessory nerve.

  • Occipital Triangle: Part of the posterior triangle, bordered by the sternocleidomastoid, the posterior belly of the digastric muscle, and the upper part of the trapezius muscle. It houses structures like the external jugular vein, branches of the cervical plexus, and sometimes parts of the accessory nerve.
  • Sterno-clavicular Triangle: Part of the posterior triangle, bounded by the sternocleidomastoid, the omohyoid muscle and the clavicle. This area houses structures associated with the brachial plexus and the subclavian vein.

Clinical Significance

• Knowledge of these triangles is crucial for clinicians in diagnosing and treating various medical conditions.

• For example, swelling in the submandibular triangle may indicate an infection of the submandibular gland.

• The location and structure within the carotid triangle are important during surgical procedures such as carotid endarterectomy.

• Examination of the posterior triangle can help assess for pathologies relating to the peripheral nerves of the brachial plexus and the accessory nerve.

• Swelling or tenderness in any of these triangles could warrant further investigation and diagnosis.