Скачать или смотреть MICROANATOMY OF PHARYNX

Microanatomy of the Pharyngeal Wall

(with arrangement of inner & outer muscle layers)

Introduction
• The pharyngeal wall has five discrete layers, two of which are fascial layers.
• From deep to superficial:
Mucosa → Submucosa → Pharyngobasilar fascia → Muscular layer → Buccopharyngeal fascia.

1. Mucosal Layer
• Nasopharynx: Ciliated pseudostratified columnar epithelium.
• Oropharynx & Laryngopharynx: Non-keratinized stratified squamous epithelium.
• Transition zone between naso- and oropharynx.

2. Submucosal Layer (Lamina Propria)
• Connective tissue with elastic fibers.
• Contains lymphoid tissue → Waldeyer’s ring.
• Thick, blends with pharyngobasilar fascia.
• Forms tonsillar capsule in some regions.

3. Pharyngobasilar Fascia (First Fascial Layer)
• Dense fibrous fascia, firmly attached to the skull base.
• Lies between submucosa and muscular layer.
• Maintains pharyngeal integrity where muscle does not extend to skull base.

4. Muscular Layer

Two functional layers:

A. Inner Layer – Longitudinal Muscles
• Stylopharyngeus (CN IX)
• Palatopharyngeus (CN X)
• Salpingopharyngeus (CN X)
Function: Elevate and shorten pharynx during swallowing and speech.
Position: These lie inside the circular constrictor muscles, running vertically.

B. Outer Layer – Circular (Constrictor) Muscles
• Superior constrictor
• Middle constrictor
• Inferior constrictor
Function: Sequential contraction to propel food bolus into the esophagus.
Position: These surround the longitudinal muscles from outside, arranged like overlapping cones.

5. Buccopharyngeal Fascia (Second Fascial Layer)
• Thin areolar fascia covering outer surface of constrictors.
• Continuous with buccinator fascia.
• Contains pharyngeal plexus of nerves and veins.
• Allows movement of pharynx against surrounding structures.
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