O, oropharynx; and H, hypopharynx; E, is the epiglottis.
Table 3.1 Muscles involved with the soft palate.
| Muscle | Action |
|---|---|
| Levator veli palatini | Elevates the soft palate |
| Pulls soft palate posteriorly to close the nasopharynx | |
| Tensor veli palatini | Pulls soft palate laterally |
| Musculus uvulae | Elevates the uvula |
| Pulls uvula laterally | |
| Palatopharyngeus | Helps close the nasopharynx |
| Elevates pharynx and larynx | |
| Palatoglossus | Elevates posterior portion of tongue |
| Narrows oropharyngeal isthmus during swallowing |
Table 3.2 Muscles involved with the oropharynx.
| Muscle | Action |
|---|---|
| Extrinsic | |
| Genioglossus | Protracts tongue |
| Depresses tongue | |
| Hyoglossus | Depresses tongue |
| Styloglossus | Retracts tongue |
| Elevates tongue | |
| Palatoglossus | Elevates tongue |
| Narrows oropharyngeal isthmus during swallowing | |
| Intrinsic | |
| Superior longitudinal | Shortens tongue |
| Curls tongue apex upward | |
| Inferior longitudinal | Shortens tongue |
| Curls tongue apex downward | |
| Transverse | Narrows tongue |
| Lengthens tongue | |
| Vertical | Broadens tongue |
| Flattens tongue | |
Oropharynx
These muscles involve the posterior portion of the airway and also involve the tongue, especially the posterior aspect of the tongue. The tongue muscles are further divided into two groups, the extrinsic and the intrinsic. The extrinsic muscles have some boney support and the intrinsic have no boney support (Table 3.2).
The human tongue is a unique structure. The tongue functions as what is known as a muscular hydrostat [10]. This means that the tongue as a structure is filled with compressible liquid. As such the tongue can go through many different movements while always maintaining a constant volume. This explains how the tongue, especially the base of the tongue, when it is laying flat, has the potential to occupy more of the oropharynx and hence be a factor in airway compromise.
The Hyoid
This is an integral structure that supports the suprahyoid and infrahyoid muscles. The position of the hyoid relative to the mandibular plane is of importance as a reliable predictor of the risk for the SRBD when viewed on a cephalometric X‐ray. The more inferior the hyoid is from the mandibular plane the greater the risk for the SRBD (reviewed in Chapter 14). The muscles that relate to the hyoid no doubt control the position of the hyoid. This group of muscles is divided into two groups, the infrahyoids and the suprahyoids (Table 3.3).
Table 3.3 Muscles related to the hyoid.
| Muscle | Action |
|---|---|
| Infrahyoids | |
| Omohyoid | Depresses hyoid |
| Sternohyoid | Depresses hyoid |
| Sternothyroid | Depresses larynx |
| Thyrohyoid | Depresses hyoid |
| Suprahyoids | |
| Stylohyoid | Elevates hyoid |
| Retracts hyoid | |
| Mylohyoid | Elevates hyoid |
| Elevates floor of mouth | |
| Digastric | Elevates hyoid |
| Aids in depression and retraction of mandible | |
| Geniohyoid | Helps move hyoid and tongue anteriorly |
Table 3.4 Muscles involved with the oropharynx.
| Muscle | Action |
|---|---|
| Superior constrictor | Constricts upper portion of pharynx |
| Middle constrictor | Constricts middle portion of pharynx |
| Inferior constrictor | Constricts lower portion of pharynx |
| Palatopharyngeus | Elevates pharynx |
| Helps close nasopharynx | |
| Salpingopharyngeus | Elevates upper and later portions of pharynx |
| Stylopharyngeus |
Elevates pharynx
|