31: Soft Palate and Pharynx

Soft Palate and Pharynx

OBJECTIVES

• To describe the origins, insertions, actions, and nerve supplies of the muscles of the soft palate and pharynx

• To describe the interrelationship of all of these muscles in chewing, swallowing, and speech

The muscles of the soft palate and pharynx are intricate in their arrangement and interrelationship. They share some common boundaries with the upper end of the digestive and respiratory systems and are important in the production of speech sounds. The soft palate forms the posterior end of the roof of the mouth. The pharynx has three components: the upper part, the nasal pharynx, is located at the posterior end of the nasal cavity; the middle part, the oral pharynx, is the back throat wall; and the lower part, the laryngeal pharynx, is below the tongue where the digestive and respiratory systems branch into their respective parts, the esophagus and larynx.

SOFT PALATE

There are five pairs of muscles in the soft palate. These muscles help move the soft palate up and back to contact the posterior throat wall and seal off the nasal cavity from the oral cavity and also to narrow the space between the two palatine tonsils. This space is called the fauces and is used in swallowing.

Palatoglossal Muscle

If you open the mouth and look at the tonsils on the side of the throat wall, you will see that there is a vertical fold of tissue in front of and behind each tonsil. These are called the anterior and posterior faucial pillars, or the palatoglossal and palatopharyngeal folds, respectively. Beneath the palatoglossal fold is the palatoglossal muscle. It originates from the posterior end of the hard palate and the anterior end of the soft palate. The fibers run downward, laterally, and forward to insert into the posterior and lateral part of the tongue. When the palatoglossal muscle contracts, it pulls the sides of the tongue up and back, pulls the soft palate down on the lateral edges, and narrows the space between the left and right anterior faucial pillars. The nerve that supplies this muscle is a part of the eleventh (XI) cranial nerve running with branches of the tenth (X) cranial nerve (Figs. 31-1 and 31-2).

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FIG. 31.1 View of the lateral throat wall looking from the midline. Mucosa has been removed and various muscles can be seen. Palatoglossal and palatopharyngeal muscles form anterior and posterior pillars, respectively; the palatine tonsil would lie between them. (From Drake RL, Vogl AW, Mitchell AWM, et al: Gray’s atlas of anatomy, London, 2008, Churchill Livingstone.) Churchill Livingstone
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FIG. 31.2 View of the lateral throat wall similar to Fig. 31-1 but with mucosa in place. Anterior and posterior pillars can be seen, as can the opening of the auditory tube in the nasal pharynx; the fold caused by the salpingopharyngeal muscle runs down from it. (From Drake RL, Vogl AW, Mitchell AWM, et al: Gray’s atlas of anatomy, London, 2008, Churchill Livingstone.) Churchill Livingstone

Palatopharyngeal Muscle

The posterior faucial pillar is formed by the palatopharyngeal muscle. It originates from the posterolateral part of the soft palate and runs downward and laterally to insert into the pharyngeal constrictor muscle and the thyroid cartilage of the larynx. When it contracts, it narrows the posterior faucial pillar and elevates the pharynx and larynx. The nerve supply is also the 10th and 11th cranial nerves (see Figs. 31-1 to 31-3).

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FIG. 31.3 Posterior view of the muscles of the soft palate. The pharyngeal constrictor muscles have been removed, and the view is from behind the throat. Notice especially how the levator veli palatini runs directly downward into the soft palate, whereas the tensor veli palatini runs downward and forward around the lateral side of the hamular process and then turns medially into the soft and hard palates. You can see how shortening of this muscle would help to tense the soft palate.

Related posts:

  1. 22: Eruption and Shedding of Teeth
  2. 3: Fundamental and Preventive Curvatures: Proximal Alignment of the Teeth and Protection of the Periodontium
  3. 16: Deciduous Dentition
  4. 34: Nervous System
  5. 24: The Tongue
  6. 10: Tooth Identification

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Jan 4, 2015 | Posted by in General Dentistry | Comments Off on 31: Soft Palate and Pharynx

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