The pharynx is a fibromuscular tube from the base of the skull to to the lower border of the cricoid cartilage. It is divided into three parts:

• Nasopharynx: behind the nasal cavity
• Oropharynx: behind the oral cavity
• Laryngopharynx: behind the larynx

Innervation

The pharyngeal muscles are supplied by the pharyngeal branch of the vagus nerve via the pharyngeal plexus. The accessory nerve contributes to the plexus as its cranial root gives motor fibres to the vagus nerve. The inferior constrictor further receives fibres from the external and recurrent laryngeal branches of the vagus. Sensory innervation in the nasopharynx, oropharynx and laryngopharynx is mediated by branches of the maxillary, glossopharyngeal and vagus nerves respectively.