Hypopharynx

Hypopharynx

The superior border of the hypopharynx is at the level of the laryngeal inlet. Its inferior border is the lower border of the cricoid cartilage where it continues into the oesophagus. The hypopharynx is commonly divided into three areas: the right and left piriform fossae, the posterior pharyngeal wall and the postcricoid region. The mucosa of these areas is, however, continuous so disease processes, such as squamous cell carci nomas, often involve more than one area as a result of overt or submucosal spread. The multifaceted complex process of swallowing, which consists of the oral, pharyngeal and oesophageal phases ( Figure 52.4 ), is mediated via a ff er ent fibres passing to the medulla oblongata through the second division of the trigem inal nerve (V), glossopharyngeal nerve (IX) and vagus nerve (X). The e ff erent pathway is from the nucleus ambiguus and is mediated via the glossopharyngeal (IX), vagus (X) and hypo glossal (XII) nerves. Damage to these major cranial nerves at an y point along their pathway , by trauma or disease, may cause dysphagia and/or aspiration. Videofluoroscopy , in which the passage of a bolus of radio- opaque f ood of di ff erent textures from the point at which it enters the oral cavity down to its passage within the stomach is examined radiologically , is the investig ation of choice when investigating swallowing (dys)function. (b)

e Oral Pharyngeal Oesophageal Superior pharyngeal constrictor muscle Middle pharyngeal constrictor muscle Inferior pharyngeal constrictor muscle Cricopharyngeus muscle Oesophagus Figure 52.4 The three phases of swallowing (a) and the muscles (b) .

Hypopharynx

The superior border of the hypopharynx is at the level of the laryngeal inlet. Its inferior border is the lower border of the cricoid cartilage where it continues into the oesophagus. The hypopharynx is commonly divided into three areas: the right and left piriform fossae, the posterior pharyngeal wall and the postcricoid region. The mucosa of these areas is, however, continuous so disease processes, such as squamous cell carci nomas, often involve more than one area as a result of overt or submucosal spread. The multifaceted complex process of swallowing, which consists of the oral, pharyngeal and oesophageal phases ( Figure 52.4 ), is mediated via a ff er ent fibres passing to the medulla oblongata through the second division of the trigem inal nerve (V), glossopharyngeal nerve (IX) and vagus nerve (X). The e ff erent pathway is from the nucleus ambiguus and is mediated via the glossopharyngeal (IX), vagus (X) and hypo glossal (XII) nerves. Damage to these major cranial nerves at an y point along their pathway , by trauma or disease, may cause dysphagia and/or aspiration. Videofluoroscopy , in which the passage of a bolus of radio- opaque f ood of di ff erent textures from the point at which it enters the oral cavity down to its passage within the stomach is examined radiologically , is the investig ation of choice when investigating swallowing (dys)function. (b)

e Oral Pharyngeal Oesophageal Superior pharyngeal constrictor muscle Middle pharyngeal constrictor muscle Inferior pharyngeal constrictor muscle Cricopharyngeus muscle Oesophagus Figure 52.4 The three phases of swallowing (a) and the muscles (b) .