Anatomy of the pharynx and esophagus

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Notes

Figure 1: Cross section of pharynx, esophagus, and larynx.
Figure 2: Waldeyer's ring. A. Posterior view. B. Cross section
Figure 3: Base of the tongue, superior view.
Figure 4: Posterior view of pharynx.
Figure 5: Posterior view of pharyngeal muscles. A. External layer. B. Internal layer.
Figure 6: Posterior view of the vasculature and nerves of the pharynx and esophagus.
Muscle
Origin
Insertion
Innervation
Action
Superior pharyngeal constrictor
  • pterygo-mandibular raphe
  • medial pterygoid plate 
  • mandible
  • Pharyngeal raphe
  • Pharyngeal branches of the vagus nerve (CN X)
  • Pharyngeal plexus
  • Sequential constriction during swallowing
Middle pharyngeal constrictor
  • stylohyoid ligament
  • the greater and lesser horns of hyoid bone
Inferior pharyngeal constrictor
  • oblique line of the thyroid cartilage 
  • side of the cricoid cartilage
Palato-pharyngeus
  • hard palate 
  • palatine aponeurosis
  • thyroid cartilage 
  • pharyngeal wall
  • Pharyngeal branch of the vagus nerve (CN X)
  • Pharyngeal plexus
  • Elevate the larynx
  • Shorten pharynx during swallowing & speaking
Salpingo-pharyngeus
  • cartilaginous part of the pharyngo-tympanic tube
Stylo-pharyngeus
  • styloid process of the temporal bone
  • thyroid cartilage
  • Glosso-pharyngeal nerve (CN IX)

Transcript

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The cervical viscera are composed of three layers based on their main functions.

The most superficial layer is the endocrine layer which contains the thyroid and parathyroid glands, then there’s the respiratory layer which contains the larynx and the trachea, and finally, the deepest layer is the alimentary layer which contains the pharynx and the esophagus.

So, let’s start with the pharynx which also has a respiratory function because it conducts air to the larynx, from where it passes through the trachea and into the lungs.

The pharynx extends from the cranial base to the inferior border of the cricoid cartilage anteriorly and the inferior border of the C6 vertebra posteriorly.

It’s located posterior to the nasal and oral cavities and it extends inferiorly past the larynx, where it continues with the esophagus.

Now, the pharyngeal wall consists of three layers: the buccopharyngeal fascia is the most external layer, covering the pharynx and, inferiorly, it’s continuous with the pretracheal fascia.

Then, there is a muscular layer which has an outer circular part and an inner longitudinal part, and the innermost mucous membrane which has a thick submucosa that contributes to the pharyngobasilar fascia.

Moreover, the posterior wall of the pharynx lies against the prevertebral layer of the deep cervical fascia.

The interior of the pharynx is divided into three parts: the nasopharynx which is located posterior to the nose and superior to the soft palate, the oropharynx which is located posterior to the mouth, and the laryngopharynx which is located posterior to the larynx.

The nasopharynx is the posterior extension of the nasal cavities and communicates with the nose through two paired openings called choanae, which are separated by the posterior end of the nasal septum.

Sources

  1. "Anatomy and physiology of the palatine tonsils, adenoids, and lingual tonsils" World Journal of Otorhinolaryngology - Head and Neck Surgery (2021)
  2. "Costanzo Physiology" Elsevier (2021)
  3. "Moore’s Clinically Oriented Anatomy" LWW (2022)
  4. "Anatomy of the pharynx and cervical esophagus" Neuroimaging Clinics of North America (2022)
  5. "Glossopharyngeal, vagus and accessory Nerves: Anatomy and Pathology" Seminars in Ultrasound CT and MRI (2023)
  6. "Anatomy of neck muscles, spaces, and lymph nodes" Neuroimaging Clinics of North America (2022)
  7. "78 - Functional anatomy of the elbow joint" Physical Diagnosis of Pain (2020)
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