Oropharynx - Anatomy & Physiology

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Introduction

The pharynx is the chamber connecting the oral cavity, nasal cavity, oesophagus and larynx. The pharynx is divided into the nasal pharynx, oral pharynx and oesophageal/laryngeal pharynx which all have different functions, innervation and develope differently.

The oropharynx is the oral section of the pharynx.

Structure and Function

• Last molar rostrally

• Epiglottis caudally

• Tongue ventrally

• Soft palate dorsally

• Endoderm

• Innervated by glossopharyngeal nerve (CN IX)

• Divided by glossopalatine arch from oesophageal pharynx

Musculature

Constrictors

• Hyopharyngeus

• Thyropharyngeus

• Cricopharyngeus

Dilators

• Stylopharyngeus

Shorten

• Pterygopharyngeus

Close Pharyngeal Arch

• Palatopharyngeus

Innervation

• Muscles from pharyngeal arch 4 innervated by vagus nerve (CN X)

• Stylopharyngeus from pharyngeal arch 3 innervated by glossopharyngeal nerve (CN IX)

Histology

• Stratified squamous epithelium

• Keratinised in ruminants

• Lamina propria contains aggregates of lymphoid tissue (called tonsils) in several parts of the oropharynx