**Question:** Which of the following parts is NOT included in the hypopharynx -

A. Epiglottis
B. Hyoid bone
C. Larynx
D. Trachea

**Correct Answer:** B. Hyoid bone

**Core Concept:** The hypopharynx is a part of the pharynx located at the level of C6-C7 vertebrae, posterior to the pharynx and anterior to the trachea, esophagus, and larynx. It is divided into three regions: cervical, thoracic, and tracheal.

**Why the Correct Answer is Right:** The hyoid bone is not part of the hypopharynx because it is a separate skeletal structure located above the larynx and forms the base of the tongue, suspension of the larynx, and connections to muscles of the head and neck.

**Why Each Wrong Option is Incorrect:**

A. Epiglottis: This is a part of the larynx, not hypopharynx. The epiglottis is a cartilaginous structure that covers the laryngeal inlet during swallowing, preventing food and drink from entering the trachea.

C. Larynx: The larynx is a part of the respiratory system and includes the epiglottis, arytenoids, aryepiglottic folds, and the thyroid and cricoid cartilages. It is separate from the hypopharynx.

D. Trachea: The trachea is a part of the respiratory system and is located inferior to the hypopharynx. It is responsible for transporting air to the lungs.

**Clinical Pearl:** The hypopharynx plays a crucial role in the swallowing process and is involved in the coordination of the pharynx, larynx, and esophagus during swallowing. Any disorder affecting the hypopharynx can lead to dysphagia, i.e., difficulty in swallowing.