Pharynx and related areas

The pharynx is a passageway shared by the digestive and respira tory systems. It has lateral, posterior, and medial walls through out, but is open interiorly in its upper regions, communicating with the nasal cavity and the oral cavity. The anterior wall of the laryngopharynx is formed by the larynx. The pharyngeal wall con sists of a mucosa, a fibrous layer, and a muscularis, which is com posed of an inner longitudinal layer and an outer circular layer.

Nasopharynx is the region of the pharynx located directly poste rior to the nasal cavity. It communicates with the nasal cavity through the choanae.

The torus tubarius is the cartilaginous rim of the auditory The pharyngeal recess is the space located directly above and behind the torus tubarius; it contains the nasopharyn-geal tonsil. The salpingopharyngeal fold is a ridge consisting of mucosa and the underlying salpingopharyngeus muscle.

Oropharynx is the region of the pharynx located directly posterior to the oral cavity. It communicates with the oral cavity through a space called the fauces. The fauces are bounded by two folds, consisting of mucosa and muscle, known as the anterior and posterior pillars.

The tonsillar bed is the space between the pillars that houses the palatine tonsil.

Laryngopharynx is the region of the pharynx that surrounds the larynx. It extends from the tip of the epiglottis to the cricoid car tilage. Its lateral extensions are known as the piriform recess.

Oral cavity: the portion of the oral cavity that is posterior to the lips and anterior to the teeth is called the vestibule. The oral cavi ty proper has a floor formed by the mylohyo-id and geniohyoid muscles, which support the tongue. It has lateral walls, consisting of the buccinator muscles and buccal mucosa, and a roof formed by the hard palate anteriorly and the soft palate posteriorly. Its posterior wall is absent and is replaced by an opening to the oropharynx, which is flanked by the pillars of the fauces.

The palate separates the nasal and oral cavities.

Hard palate is formed by the palatine process of the maxilla and the horizontal palate of the palatine bone. Its mucosa is supplied with sensory fibers from CN V2.

Soft palate consists of a fibrous membrane, the palatine aponeurosis, covered with mucosa. The portion that hangs down in the midline is the uvula.

The tongue is a mobile, muscular organ necessary for speech. It is divisible into an anterior two-thirds and a posterior one-third by the sulcus terminalis.

Muscles of the tongue. These include the intrinsic and extrinsic muscles (i. e., palatoglossus, stylogiossus, hyoglos – sus, genioglossus). All of the muscles are innervated by CN XII except the palatoglossus, which is supplied by CN X. Arterial supply: The tongue is supplied by the lingual branch of the external carotid aitery.

Venous drainage. The lingual veins, which lie on the un-der-surface of the tongue, drain to the internal jugular veins.

Lymphatic drainage. The tip of the tongue drains to the submental nodes, and the remainder of the anterior two-thirds drains first to submandibular, then to deep cervical nodes. The posterior one-third drains directly to deep cervi cal nodes.

Date: 2016-02-19; view: 358; Нарушение авторских прав