Which of the following is not classified as an infrahyoid muscle?

The stylohyoid muscle is not classified as an infrahyoid muscle because it is located above the hyoid bone in the neck, whereas infrahyoid muscles are found below the hyoid. The infrahyoid muscles play a crucial role in the movement of the hyoid bone and the larynx during swallowing and speaking.

In contrast, the omohyoid, thyrohyoid, and sternothyroid muscles are all located below the hyoid bone. The omohyoid assists in lowering the hyoid and stabilizing it, the thyrohyoid elevates the thyroid cartilage and helps in swallowing, and the sternothyroid also aids in depressing the larynx after swallowing. Understanding the anatomical positions and functions of these muscles helps clarify their classification and significance in neck movement and function.