Overview of the anatomy of the head and neck area

In this step we will explain the most important anatomical structures of the head and neck region, which is essential to understand the pathological neck masses.

Next to the patient history, knowledge of anatomy is of great importance to formulate a differential diagnosis. In this step we will give a simplified overview of the following elements of the anatomy in the neck:

• The musculature
• The blood supply
• The nerves
• The lymphoid node regions
• Other important structures of the neck

Please use your own medical books or other reliable sources such as the Sobotta Atlas of Anatomy, Vol. 3, 16th edition, Clinically Oriented Anatomy 8th edition, or UpToDate as an extra source for images.

Anatomy of the head and neck area.

First, we will start with the musculature of the neck. The broadest, most superficial muscle of the neck is the platysma and covers the anterior surface of the neck. The platysma overlaps the sternocleidomastoid muscle, the strongest muscle in the neck, on both sides. The sternocleidomastoid flexes the neck and extends the head. Medially to the sternocleidomastoid muscle, we can find the infrahyoid muscles or also known as the strap muscles and the suprahyoid muscles. The infrahyoid muscles consist of four pairs of muscles namely the sternohyoid, sternothyroid, thyrohyoid and omohyoid muscles. The main functions are related to swallowing and speech. The mylohyoid and the digastric muscles belong to the suprahyoid muscles.

The blood supply in the head and neck area is mainly supplied by the common carotid artery. The common carotid artery splits into the internal and external carotid artery, which has many branches to the different structures of this region. The venous supply mainly drains into the jugular veins, which has an internal and external system. Next to these vessels lies another important structure, the vagal nerve and interfaces with the parasympathetic control of the heart, lungs, and digestive tract. Another important nerve running behind and innervating the sternocleidomastoid muscle and trapezius muscle is the accessory nerve, also known as the 11th cranial nerve. Lastly, the 12th cranial nerve, also known as the hypoglossal nerve, is an important structure innervating the tongue and other swallowing muscles.

There are several lymph node stations in the neck, which can be divided into level I-VII. Level I is the submandibular region, II, III, IV are the parajugular lymph nodes. Level V represents the posterior triangle of the neck, posterior to the sternocleidomastoid muscle. Level VI is considered to be the central compartment of the neck, and just caudally, behind the sternum is level VII (upper mediastinum). Understanding the lymph node levels is important as lymphatic drainages are dependent on the anatomic areas.