Layers of Pharynx

Layers of the Pharyngeal Wall

The pharyngeal wall is composed of five distinct layers, arranged from deep to superficial:

1. Mucosal layer
2. Submucosal layer
3. Pharyngobasilar fascia
4. Muscular layer
5. Buccopharyngeal fascia

1️⃣ Mucosal Layer of Pharynx

• This innermost layer lines the entire pharyngeal cavity.

• It is continuous with the mucous membranes of connected structures:
  Eustachian tube, nasal cavity, oral cavity, larynx, esophagus.

🔬 Type of Epithelium:

• Nasopharynx: Ciliated pseudostratified columnar epithelium (respiratory type)

• Oropharynx & Laryngopharynx: Non-keratinized stratified squamous epithelium

🧭 Transitional Zone: The change in epithelium occurs at the lower end of the pharynx.

2️⃣ Submucosal Layer (Lamina Propria) of Pharynx

• Lies beneath the mucosa.
• Composed of elastic connective tissue.
• Contains Waldeyer's Ring

What is Waldeyer's Ring?

3️⃣ Pharyngobasilar Fascia (Pharyngeal Aponeurosis)

• A fibrous layer that is firmly attached to the base of the skull.

🎯 Why is it Important?

• The muscular layer is deficient at the skull base.
• This fascia compensates by providing support and structural integrity at the upper end of the pharynx.

4️⃣ Muscular Layer of Pharynx

➤ Outer Circular Muscles (Constrictors):

• Superior constrictor
• Middle constrictor
• Inferior constrictor

These muscles overlap like stacked bones.

➤ Inner Longitudinal Muscles:

• Stylopharyngeus
• Salpingopharyngeus
• Palatopharyngeus

Detailed discussion of pharyngeal muscles is covered in a separate post.

5️⃣ Buccopharyngeal Fascia

• The outermost layer, made of loose areolar connective tissue.

• Covers the pharyngeal constrictor muscles.

• Continues anteriorly with the buccinator fascia.

💡 Clinical Relevance:

• Contains the pharyngeal plexus of nerves and veins.
• Acts as a surgical plane and potential space in infections.

✅ Summary Table