THE PHARYNX nasopharynx oropharynx laryngopharynx
Applied anatomy The pharynx is the common passage of the respiratory tract and the digestive tract. It extends from the base of the skull to the inlet of the esophagus at the level of the sixth cervical vertebra. It’s about 1214cm long. oropharynx laryngopharynx
Structure of pharyngeal wall From with outwards it consists of four layers 1.Mucous membrane 2. Pharyngeal aponeurosis 3. Muscular coat 4. Buccopharyngeal fascia
1. Mucous membrane It lines the pharyngeal cavity and is continuous with mucous membrane of eustachian tube, nasal cavity, mouth, larynx and oesophagus. The epithelium is ciliated columnar in nasopharynx and stratified squamous elsewhere
2.Pharyngeal aponeurosis It is a fibrous layer which lines the muscular coat and is particularly thick near the base of skull but is thin and indistinct inferiorly
3. Muscular coat It consist of two layers of muscles with three muscles in each layer 1. External layer: contains superior, middle and inferior constrictor muscles. 2. Internal layer: contains stylopharyngeus, salpingopharyngeus and palatoparyngeus muscles
4. Buccopharyngeal fascia Covers outer surface of constrictor muscles. Above the upper border of superior constrictor, it blends with pharyngeal aponeurosis
Pharynx: median section
Pharynx Nasopharynx Oropharynx laryngopharynx
1. nasopharynx opening into the nasal cavity 2. oropharynx opening into the oral cavity 3. laryngopharynx opening into larynx