The most prominent surface landmarks include the hyoid bone, which can be palpated in the upper neck just above the thyroid cartilage. The thyroid cartilage (Adam's apple) is easily visible and palpable, especially in males. Below this is the cricoid cartilage, which forms a complete ring around the trachea.
The sternocleidomastoid muscle is the most prominent surface feature, running diagonally from the mastoid process behind the ear to the sternum and clavicle. This muscle divides the neck into anterior and posterior triangles. The anterior triangle contains important structures like the carotid arteries, jugular veins, and thyroid gland, while the posterior triangle contains the subclavian vessels and brachial plexus.
The external jugular vein is often visible running superficially along the sternocleidomastoid muscle. The carotid pulse can be palpated in the carotid triangle, medial to the sternocleidomastoid muscle at about the level of the thyroid cartilage.
The suprasternal notch (jugular notch) is the depression at the top of the sternum between the two clavicles. The thyroid gland may be palpable, particularly when enlarged, and moves with swallowing. Lymph nodes may be palpable along the sternocleidomastoid muscle and in the submandibular region.
Clinically, the neck is often divided into triangles for examination purposes. The anterior triangle is bounded by the midline, mandible, and sternocleidomastoid muscle, while the posterior triangle is bounded by the sternocleidomastoid, trapezius, and clavicle.
This surface anatomy is crucial for clinical examination, procedures like central line placement, and understanding the relationships between deeper structures.