Gag Reflex

Clinical Exam

The mouth is opened and a finger is inserted through the oral cavity into the oropharynx.  The muscle tone of the oropharynx is assessed and the stimulation of the oropharynx results in a gag reflex.  Please note that the response to this stimulation is variable between dogs and assessment is subjective.  Also this examination should only be performed in cooperative patients and ideally the examiner should wear gloves.

Anatomic Pathway

The mouth is opened and a finger is inserted through the oral cavity into the oropharynx.  The muscle tone of the oropharynx is evaluated, these muscles are innervated by glossopharyngeal (CN IX) and vagus (CN X) nerves.  The oropharynx is stimulated by the touch of the finger with the afferent pathway traveling along both the glossopharyngeal and vagal nerves.  The efferent pathway again involves the glossopharyngeal and vagal nerves as well as the pharyngeal muscles.

It is important to note that there is likely stimulation of the tongue as one passes through the oral cavity to the oropharynx.  Thus the stimulation will also involve the trigeminal nerve (CN V) and the hypoglossal nerve (CN XII).

Overview of Anatomy

The mouth is opened and a finger is inserted through the oral cavity into the oropharynx.  The muscle tone of the oropharynx is evaluated, these muscles are innervated by glossopharyngeal (CN IX) and vagus (CN X) nerves.  The oropharynx is stimulated by the touch of the finger with the afferent pathway traveling along both the glossopharyngeal and vagal nerves.  The efferent pathway again involves the glossopharyngeal and vagal nerves as well as the pharyngeal muscles.

It is important to note that there is likely stimulation of the tongue as one passes through the oral cavity to the oropharynx.  Thus the stimulation will also involve the trigeminal nerve (CN V) and the hypoglossal nerve (CN XII).

Anatomic Sections

The mouth is opened and a finger is inserted through the oral cavity into the oropharynx.  The muscle tone of the oropharynx is evaluated, these muscles are innervated by glossopharyngeal (CN IX) and vagus (CN X) nerves.  The oropharynx is stimulated by the touch of the finger with the afferent pathway traveling along both the glossopharyngeal and vagal nerves.  The efferent pathway again involves the glossopharyngeal and vagal nerves as well as the pharyngeal muscles.

It is important to note that there is likely stimulation of the tongue as one passes through the oral cavity to the oropharynx.  Thus the stimulation will also involve the trigeminal nerve (CN V) and the hypoglossal nerve (CN XII).