The soft palate is the posterior muscular extension of the hard palate which together, with the soft palate, make up the palate of the oral cavity and the floor of the nasal cavity. This article will discuss the soft palate in detail including its borders, its function, its general anatomy, its musculature and its possible pathology.
The soft palate is bordered:
- superiorly by the respiratory mucosa of the nasal cavity.
- inferiorly by the mucosa of the oral cavity.
- Posteriorly it has no borders and hangs at an inferior angle towards the larynx, where it dangles the uvula in its midline.
- Posterolaterally, however, it forms part of the superior portion of the palatoglossal and palatopharyngeal folds.
- Anteriorly it is connected to the bony hard palate via an aponeurotic plate at the level of the vibrating line. This plate is a tendinous aponeurosis which extends from the tensor veli palatini muscles on either side.
The soft palate is multi-functional and aids speech and the pronunciation of velar consonants along with the dorsum of the tongue. When swallowing, it rises to close the nasal passages and prevent any food or liquid from entering into the nasal cavity. It does the same thing for the larynx when sneezing. The uvula helps produce the gag reflex when touched.
The soft palate makes up approximately one-third of the posterior portion of the palate its oral mucosal lining is covered with mucous secreting salivary glands. It has no bony frame and is made up entirely of various muscle fibers. The musculature is comprised of five main structures including the musculus uvulae, the tensor veli palatini, the levator veli palatini, the palatopharyngeus muscle and the palatoglossus muscle.
The musculus uvulae originate in the posterior nasal spine and the palatal aponeurosis. Its fibers insert into the muscle of the opposite side and it elevates and pulls the uvula laterally. It is innervated by the pharyngeal plexus which takes its motor fibers from the vagus nerve (CN X) and the cranial portion of the accessory nerve (CN XI). This plexus innervates all the soft palate muscles, save the tensor veli palatini muscle. It may be bifid in appearance, however, that does not affect the patient in any way other than aesthetically.
Tensor veli palatini muscle
The tensor veli palatini muscle originates in the cartilaginous part of the auditory tube as well as the scaphoid fossa of the sphenoid bone. It inserts into the palatine aponeurosis and broadens the soft palate by pulling it laterally. It is innervated by a muscular branch of the mandibular nerve (CN V/III).
Levator veli palatini muscle
The levator veli palatini muscle arises from the cartilaginous portion of the auditory tube and the petrous part of the temporal bone. It inserts into the palatine aponeurosis as well as the fibers of the muscle on the opposite side. It elevates both the soft palate and pulls it posteriorly, which helps close the nasopharynx during swallowing.
The palatopharyngeus muscle attaches proximally to the posterior border of the hard palate and also to the palatine aponeurosis. It distally inserts itself on the posterior aspect of the lamina of the thyroid cartilage of the larynx. It helps close the nasopharynx as well as raising the larynx and the pharynx.
The palatoglossus muscle arises from the palatine aponeurosis and terminates on the lateral aspect of the tongue where its fibers intermingle with the intrinsic musculature of the tongue. It acts in narrowing the oropharyngeal isthmus during digestion and also elevates the tongue.
Possible pathological conditions that may affect the soft palate include mucosal lesions such as herpangina, pemphigus vulgaris, and migratory stomatitis. Small petechiae upon the uvula and region of the soft palate may be symptoms of streptococcal pharyngitis, but can also be a harmless symptom post fellatio. Developmental anomalies that can affect the soft palate, in particular, the uvula include a congenital cleft palate with a cleft uvula.