The Pharynx: Divisions and Innervation
The pharynx is a muscular tube extending from the base of the skull to the inferior border of the cricoid cartilage. It is divided into three parts: nasopharynx, oropharynx, and laryngopharynx.
| Division | Key Features |
|---|---|
| Nasopharynx | Superior to soft palate; contains pharyngeal tonsils (adenoids) and opening of the Eustachian (auditory) tube. |
| Oropharynx | Between soft palate and epiglottis; contains palatine tonsils. |
| Laryngopharynx | Between epiglottis and cricoid cartilage; contains piriform recesses. |
High-Yield Clinical Pearls:
- Innervation: Motor to most muscles of the pharynx is provided by the Pharyngeal Plexus (CN X). The stylopharyngeus is the exception (innervated by CN IX).
- Sensory: Nasopharynx (CN V2), Oropharynx (CN IX), Laryngopharynx (CN X).
- Gag Reflex: Afferent limb is CN IX; efferent limb is CN X.
- Piriform Recess: A common site for foreign body impaction; injury here can damage the internal laryngeal nerve.