Anatomy, Head and Neck, Styloid Process

The styloid process is a cylindrical, slender, needle-like projection of varying lengths averaging 2 to 3 cm. The styloid process projects from the inferior part of the petrous temporal bone and offers attachment to the stylohyoid ligament and the stylohyoid, stylopharyngeus, and styloglossus muscles. Through these structures, the styloid process facilitates the movement of the tongue, pharynx, larynx, hyoid bone, and mandible. Significant vessels and nerves surround the styloid process. The internal jugular vein, internal carotid artery, and glossopharyngeal nerve (CN IX), vagus nerve (CN X), and accessory nerve (CN XI) lie medial to the styloid process. The occipital artery and hypoglossal nerve (CN XII) run along its lateral side. Originating as a part of Reichert's cartilage forming from the second pharyngeal arch, it undergoes endochondral ossification in the late stages of pregnancy through the first decade of life. The structure shows variations in length, angulation, and other morphological features between individuals. Although these physiological differences are often found incidentally, some patients might develop a constellation of symptoms known as Eagle syndrome. The symptomatology of Eagle syndrome occurs secondary to irritation and/or compression of surrounding structures from an abnormal styloid process.