Your cart is currently empty!
M01.04.005 Pharynx
The pharynx is a muscular tube that connects the oral and nasal cavities to the larynx and esophagus. It plays a critical role in both respiratory and digestive systems. This article explores its structure, neurovascular supply, and clinical significance.
Structural Overview
Location
- Begins: Base of the skull.
- Ends: Inferior border of the cricoid cartilage (C6).
Divisions of the Pharynx
- Nasopharynx
- Oropharynx
- Laryngopharynx
Detailed Anatomy
1. Nasopharynx
- Location: Between the base of the skull and the soft palate.
- Function: Respiratory function; conditions and propagates inspired air to the larynx.
- Epithelium: Ciliated pseudostratified columnar epithelium with goblet cells.
- Special Structure: Contains adenoid tonsils (enlarged during childhood).
Clinical Relevance: Enlarged Adenoid Tonsils
- Cause: Viral infections or chronic inflammation.
- Effect: Obstruction of Eustachian tube leading to chronic otitis media with effusion (“glue ear”).
2. Oropharynx
- Location: Between the soft palate and superior border of the epiglottis.
- Contains:
- Posterior one-third of the tongue.
- Lingual and palatine tonsils.
- Superior pharyngeal constrictor muscle.
- Part of Waldeyer’s ring (lymphoid tissue network).
- Function: Involved in swallowing (voluntary and involuntary phases).
3. Laryngopharynx
- Location: Between the superior border of the epiglottis and the inferior border of the cricoid cartilage (C6).
- Special Features:
- Pisiform fossae (located laterally).
- Contains middle and inferior pharyngeal constrictors.
- Function: Propels food into the esophagus.
Clinical Relevance: Pharyngeal Diverticulum
- Cause: Dysfunction of the cricopharyngeus muscle.
- Effect: Formation of a pouch (diverticulum), leading to dysphagia.
Muscles of the Pharynx
| Group | Muscles | Function | Innervation |
|---|---|---|---|
| Circular | Superior, Middle, Inferior Pharyngeal Constrictors | Sequential contraction constricts lumen and propels food. | Vagus nerve (CN X). |
| Longitudinal | Stylopharyngeus, Palatopharyngeus, Salpingopharyngeus | Shorten, widen pharynx; elevate larynx during swallowing. | Vagus (CN X) and Glossopharyngeal (CN IX). |
Innervation
| Aspect | Source |
|---|---|
| Motor | Vagus nerve (except stylopharyngeus by CN IX). |
| Sensory | Glossopharyngeal nerve; nasopharynx (CN V2); inferior laryngopharynx (internal branch of CN X). |
Vasculature
| Arterial Supply | Source |
|---|---|
| Ascending pharyngeal artery | External carotid artery. |
| Facial artery branches | External carotid artery. |
| Lingual and maxillary arteries | External carotid artery. |
| Venous Drainage | Destination |
|---|---|
| Pharyngeal venous plexus | Internal jugular vein. |
Points to Remember
- The pharynx acts as a passage for air and food, connecting the nasal cavity, oral cavity, and esophagus.
- It is divided into nasopharynx, oropharynx, and laryngopharynx, each with distinct roles and structures.
- Adenoid tonsils and Waldeyer’s ring play vital roles in immune defense but can cause clinical issues when enlarged.
- Proper muscle coordination is essential for swallowing; dysfunction can lead to conditions like pharyngeal diverticulum.
- The pharynx is richly supplied by external carotid artery branches and innervated primarily by the vagus and glossopharyngeal nerves.
Recommended Resources
- Gray’s Anatomy for in-depth pharyngeal structure.
- Clinical Anatomy by Richard S. Snell for practical applications.