Anatomy of Neck

Neck is the body portion that separates the head from the rest of the body. The major components present in the neck are jugular veins, carotid arteries, nerves, portion of esophagus, vocal cords or larynx, cervical spine (that encloses spinal cord) and sternocleidomastoid muscles.

The jugular veins comprises internal and external veins. The interior jugular vein receives blood from the face, brain and neck; whereas, the external jugular vein collects blood from the cranium, deep tissues of face. The external jugular vein consists of the anterior external or posterior external vein. The former drains blood from the lower jaw and voice box, while the latter collects blood from the back of the neck.

The carotid arteries distribute blood to the head and neck. There are two major carotid arteries that extend on each side of the neck. The left carotid artery originates from the arch of the aorta, while the right one originates from the brachiocephalic trunk. Each of these carotid arteries are categorized into internal and external carotid artery. The nerves in the neck portion are cranial nerves and cervical nerves. The pharynx, larynx, trachea and portion of esophagus are collectively referred to as visceral column.

The bone present in the neck is referred to as cervical spine. It originates just below the skull and comprises seven vertebrae and eight pairs of nerves. The seven vertebrae are symbolized as C1, C2, C3, C4, C5, C6 and C7. Cartilaginous discs are present between two vertebrae. The cervical spine of the neck is comparatively smaller than other vertebrae of the spinal column. From top to bottom, it is slightly curved in a convex manner. The cervical spine is responsible for movement of head, protection of skull and spinal cord and supporting the muscles and ligaments of the neck. It also helps in supporting the blood vessels and nerves located in the neck.

The neck muscles and structures are highly complicated, hence for better understanding, they are divided into triangular components. The digastric muscle extends from the mastoid (posterior to external ear), joins the hyoid (bone at the base of the tongue) and ascends to the mandible. The large sternocleidomastoid muscle, which is attached to the mastoid process of temporal bone, divides the neck into two major triangles, namely the anterior and posterior triangle.

The posterior triangle is highly muscular in comparison to the anterior one. It is surrounded by trapezius (posterior), sternocleidomastoid (anterior) and clavicle (inferior). Posterior triangle is of two types, supraclavicular and occipital triangles. Majority of the cervical nerves originates from this posterior triangle. The anterior triangle, on the other hand, is surrounded by mandible (superior), midline (medial) and sternocleidomastoid (lateral). It comprises vital structures and is further divided into four triangles, namely, muscular, carotid, submental and submandibular triangle.

The spinal nerve passes through sternocleidomastoid and trapezius, and is responsible for transferring nerve impulses to both the muscles. In addition, some of the important features of the neck anatomy are thyroid gland, parathyroid gland, hyoid bone and Adam's apple (more prominent in adult males than females).