23. Pharynx - Macroscopic, microscopic, ultramicroscopic and functional characteristics. Blood and nerve supply.

PHARYNX

• The pharynx is a muscular tube that connects the oral & nasal cavity to the larynx and oesophagus
• Extends from the skull down to the level of C₆ vertebra
• It acts as respiratory & digestive tube.
• It is divided into 3 parts:

1. Nasopharynx - behind the nasal cavity
2. Oropharynx - " " oral cavity
3. Laryngopharynx - behind the larynx

Nasopharynx:

• Aproximately 2-3cm wide and 3-4cm long.
• contains:

1. Opening of the auditory tube.
2. Tubal elevation & fold
3. Pharyngeal recess
4. Pharyngeal tonsils.

The oropharynx

• contains:

1. Palato-glossal fold
2. Palato-pharyngeal fold
3. Palatine tonsils.

The laryngopharynx:

• Contains:

1. Valleculae: depressions formed btw. midline mucosal fold and 2 lateral folds that connect the tongue to the epiglottis

Layers of the pharynx:

1. Buccopharyngeal fascia

• ↳ It is the outermost layer.
• ↳ thin, covering the external surface of muscle
• ↳ Forwards: it covers the buccinator m. Backwards: contact with the prevertebral fascia

2. Muscle Coat: (next page)

3. Pharyngo-basilar fascia

• ↳ It lies the inner surface of the muscle coat.
• ↳ It formes a ridge wall for the nasopharynx to keep it permanently open.
• ↳ It is attached superiorly to bones of the skull (occipital & temporal bones) And posteriorly to the pharyngeal raphe

4. The mucosa:

• ↳ Is the innermost layer of the pharynx.