Anatomy of the Pharynx

Overview

• Follow-up to the oral cavity lecture.
• The pharynx: connects the oral cavity to the esophagus.
• Functions as a control point for breathing and swallowing.

Parts of the Pharynx

1. Nasopharynx

   • Connected to the nasal cavity (Pars nasalis).
   • Located at the level of the 1st to 2nd cervical vertebrae.
   • Attachment points at the base of the skull (Fornix Pharyngis).
   • Key features:
     • Choanae: Border between nasal cavity and pharynx.
     • Auditory (Eustachian) Tube: Connects middle ear to pharynx.
       • Functions: Equalizes pressure, drains the middle ear.
       • Opens at ostium pharyngeum tubae auditivae.
     • Tonsils: Pharyngeal tonsil (adenoids) and tubal tonsils.

2. Oropharynx

   • Connected to the oral cavity.
   • Located at the level of the 3rd to 4th cervical vertebrae.
   • Bordered by the soft palate and epiglottis.
   • Connection through isthmus faucium (oropharyngeal isthmus).

3. Laryngopharynx

   • Connected to the larynx and continues to the esophagus.
   • Located at the level of the 5th to 6th cervical vertebrae.
   • Key structures:
     • Laryngeal inlet and esophagus opening.
     • Piriform fossa: Depression on either side.

Layers of the Pharyngeal Wall

1. Tunica Mucosa

   • Inner epithelial lining.
   • Nasopharynx: Pseudostratified epithelium with cilia and goblet cells.
   • Remainder: Stratified squamous non-keratinized epithelium.

2. Tela Submucosa

   • Contains connective tissue, blood and lymph vessels, glands.

3. Tunica Muscularis

   • Inner circular and outer longitudinal muscle fibers.
   • Facilitates pharyngeal peristalsis.

4. Tunica Adventitia

   • Outer layer of collagen fibers.

Muscles of the Pharynx

Pharyngeal Constrictors

• Superior Pharyngeal Constrictor
  • Origin: Pterygoid process, pterygomandibular raphe, mylohyoid line.
  • Insertion: Pharyngeal raphe.
• Medial Pharyngeal Constrictor
  • Origin: Hyoid bone.
  • Insertion: Pharyngeal raphe.
• Inferior Pharyngeal Constrictor
  • Origin: Thyroid and cricoid cartilages.
  • Insertion: Pharyngeal raphe.

Pharyngeal Elevators

• Stylopharyngeus Muscle
  • Origin: Styloid process.
  • Insertion: Lateral wall of the pharynx.
• Palatopharyngeus Muscle
  • Origin: Soft palate aponeurosis.
  • Insertion: Lateral wall of the pharynx.
• Salpingopharyngeus Muscle
  • Origin: Walls of the auditory tube.
  • Insertion: Palatopharyngeus fibers.

Functions of the Muscles

• Constrictors aid in peristalsis by contracting the pharynx.
• Elevators lift the pharynx during swallowing.

Conclusion

• Summary of pharynx structure, its parts, wall layers, and muscles.
• Next topic: Anatomy of the Esophagus.