It supports the weight of the head and protects the nerves that transmit sensory and motor information between the brain and the rest of the body.

This triangle contains the sternocleidomastoid, trapezius, splenius capitis, levator scapulae, omohyoid, anterior, middle and posterior scalene muscles.

The thyroid cartilage of the larynx forms a bulge in the midline of the neck called the Adam's apple.

The line of the common and the external carotid arteries can be marked by joining the sterno-clavicular articulation to the angle of the jaw.

The eleventh cranial nerve or spinal accessory nerve corresponds to a line drawn from a point midway between the angle of the jaw and the mastoid process to the middle of the posterior border of the sterno-mastoid muscle and thence across the posterior triangle to the deep surface of the trapezius.

The external jugular vein can usually be seen through the skin; it runs in a line drawn from the angle of the jaw to the middle of the clavicle, and close to it are some small lymphatic glands.

The anterior jugular vein is smaller and runs down about half an inch from the middle line of the neck.

[15] The circumference of the neck typically varies between males and females due to differences in body composition, muscle mass, and hormonal influences.

Hormonal differences also play a significant role, as testosterone, which is present at higher levels in men, promotes muscle growth, including in the neck area.

Its absence in fish and aquatic arthropods is notable, as many have life stations similar to a terrestrial or tetrapod counterpart or could otherwise make use of the added flexibility.