The pharynx is a tube 12 to 14 cm long that extends from the base of the skull to the level of the 6th cervical vertebra. It lies behind the nose,mouth and the larynx and is wider at its upper end.
STRUCTURES ASSOCIATED WITH THE PHARYNX.
Superiorly- the inferior surface of the base of the skull.
Inferiorly- it is continuous with the oesophagus.
Anteriorly- the wall is incomplete because the openings into the nose,mouth and larynx.
Posteriorly- areolar tissue,involuntary muscle and the bodies of the first six cervical vertebrae.
The pharynx is divided into:
1) THE NASOPHARYNX.
The nasal part of the pharynx lies behind the nose above the level of the soft palate. On its lateral walls are the two openings of the auditory tubes ,one leading to each middle ear. On the posterior wall are the pharyngeal tonsils,consisting of lymphoid tissue.
2)THE OROPHARYNX.
The oral part of the pharynx lies behind the mouth,extending from below the level of the soft palate to the level of the upper part of the body of the 3rd cervical vertebra. The lateral walls of the pharynx blend with the soft palate to form two folds on each side.
3) THE LARYNGOPHARYNX.
The laryngeal part of the pharynx extends from the oropharynx above and continues as the oesophagus below from the level of the 3rd to the 6th cervical vertebrae.
FUNCTIONS.
1) PASSAGEWAY FOR AIR AND FOOD. The pharynx is involved in both the respiratory and the digestive systems: air passes through the nasal and oral sections,and food through the oral and laryngeal sections.
2)WARMING AND HUMIDIFYING.
By the same methods as in the nose,the air is further warmed and moistened as is passes through the pharynx.
3)TASTE.These are olfactory nerve endings of the sense of taste in the epithelium of the oral and pharyngeal parts.
4) Hearing.
5)Protection.
6)Speech.
