Introduction
Shayne C. Gad in Toxicology of the Gastrointestinal Tract, 2018
The lips or labia are fleshy folds surrounding the opening of the mouth. They are covered externally by skin and internally by a mucous membrane. There is a transition zone where the two kinds of covering tissue meet. This portion of the lips is nonkeratinized, and the color of the blood in the underlying blood vessels is visible through the transparent surface layer. The inner surface of each lip is attached to its corresponding gum by a midline fold of mucous membrane called the labial frenulum. The orbicularis oris muscle and connective tissue lie between the skin and the mucous membrane of the oral cavity. During chewing, contraction of the buccinator muscles in the cheeks and orbicularis oris muscle in the lips helps keep food between the upper and lower teeth. The vestibule of the oral cavity is a space bounded externally by the cheeks and lips and internally by the gums and teeth. The oral cavity proper is a space that extends from the gums and teeth to the fauces, the opening between the oral cavity and the pharynx or throat. The hard palate—the anterior portion of the roof of the mouth—is formed by the maxillae and palatine bones, is covered by mucous membrane, and forms a bony partition between the oral and nasal cavities. The soft palate, which forms the posterior portion of the roof of the mouth, is an arch-shaped muscular partition between the oropharynx and nasopharynx that is lined by mucous membrane. Hanging from the free border of the soft palate is a conical muscular process called the uvula. During swallowing, the soft palate and uvula are drawn superiorly, closing off the nasopharynx and preventing swallowed foods and liquids from entering the nasal cavity. Lateral to the base of the uvula are two muscular folds that run down the lateral sides of the soft palate: Anteriorly, the palatoglossal arch extends to the side of the base of the tongue; posteriorly, the palatopharyngeal arch extends to the side of the pharynx. The palatine tonsils are situated between the arches, and the lingual tonsils are situated at the base of the tongue. At the posterior border of the soft palate, the mouth opens into the oropharynx through the fauces.
Oral cavity
Paul Ong, Rachel Skittrall in Gastrointestinal Nursing, 2017
Separation of the oral and nasal cavities occurs through the development of the palate. The palate is divided into the hard palate that forms the roof of the mouth anteriorly and the soft palate posteriorly.
Anatomy of the Pharynx and Oesophagus
John C Watkinson, Raymond W Clarke, Terry M Jones, Vinidh Paleri, Nicholas White, Tim Woolford in Head & Neck Surgery Plastic Surgery, 2018
Upon bilateral contraction, the muscles tauten predominantly the anterior part of the soft palate and depress the arch. Unilateral contraction of the muscles moves the soft palate in the direction of the pull. A primary function of the tensor veli palatini muscle is also presumed to be associated with opening the pharyngotympanic tube during swallowing and yawning to allow for equalization of nasopharyngeal and middle ear air pressure. This explains why patients with cleft palate will almost universally have otitis media with effusion; due to a failure of the midline connection, the tensor veli palatini cannot pull open the pharyngotympanic tube and, so, aeration of the middle ear as well as protecting it from the transmission of infections from the pharynx is negligible. The tensor veli palatini is the only muscle of the palate that is supplied by a branch of the mandibular division of the trigeminal nerve – the nerve to medial pterygoid. The rest are supplied by the cranial part of the accessory nerve via the pharyngeal plexus. Levator veli palatini is a cylindrical muscle that arises from a small tendon on the inferior, roughened, portion of the petrous temporal bone, known as the quadrate area, situated in front of the inferior opening of the carotid canal. Some of its fibres also originate from the lower part of the cartilaginous pharyngotympanic tube and yet more from the vaginal process of the tympanic bone. It inserts onto the nasal surface of the palatine aponeurosis and sits between the two heads of the palatopharyngeus muscle, forming a rounded belly. The levator muscles pass anteromedially and together they form a V-shaped sling just above and behind the palatine aponeurosis, which allows elevation and slight retraction of the vertical posterior part of the soft palate when closure of the nasopharynx is required. The soft palate then touches the posterior pharyngeal wall, closing off the nasopharyngeal isthmus to prevent nasal regurgitation during speech and swallowing. Additionally, its fibres also pull the lateral nasopharyngeal wall anteromedially to narrow that space. The effects of levator veli palatini on the pharyngotympanic tube and its role in the equalization of air pressure are controversial. This muscle, along with the palatoglossus, palatopharyngeus and uvular muscle, are all supplied by the cranial part of the accessory nerve via the pharyngeal plexus. Musculus uvulae lies between the two laminae of the palatine aponeurosis and arises from the posterior nasal spine on the palatine bone as well as from the superior surface of the aponeurosis. It sits above the V-shaped sling formed by the two levator veli palatini muscles and runs backwards above it to insert into the uvular mucosa. Most of this small muscle is fused in the midline. Its function is to act in conjunction with the levator veli palatini muscles to retract and thicken the mid-third of the soft palate, thus closing the nasopharyngeal isthmus. As the two muscle bellies run at 90 degree angles to each other, when they contract, a ‘levator eminence’ is formed. This helps in the finally sealing off of the nasopharynx during swallowing.
Gustatory Function of the Soft Palate
Published in Acta Oto-Laryngologica, 2002
Minoru Ikeda, Akihiro Ikui, Hiroshi Tomita
Several characteristics of the gustatory function of the soft palate principally elucidated by our own recent investigations, as well of those of others, are described. The soft palate has a gustatory function which is independent of the tongue and is innervated by the greater petrosal nerve. Taste papillae of the soft palate are morphologically similar to the fungiforme papillae which exist on the anterior part of the tongue. In individuals aged , 20 years, gustatory functions of the soft palate, examined by means of the electro-gustatory and filter paper disk test's are as good as those of the tongue innervated by the chorda tympani and glossopharyngeal nerve. In younger individuals, the gustatory function of the soft palate plays as important a role as that of the tongue. Gustatory thresholds of the soft palate, as well as those of other sites innervated by other taste nerves, tend to be elevated with aging, and the degree of elevation in the soft palate is much greater than that of other sites. The most sensitively perceived taste at the soft palate is a sweet taste in the majority of subjects. Taste papillae of the palate in rats become flattened and decrease in number with age. These changes are more prominent in zinc-deficient rats.
Elevation of the soft palate in speech and swallowing in normal female participants and females with motor neuron disease: an innovative procedure for measuring palatal elevation
Published in International Journal of Language & Communication Disorders, 2002
Alison Perry, Karen Anderson, Ruth Lean, Susan Cotton
The aim was to measure the angle of elevation of the soft palate during the separate conditions of swallowing of pudding, swallowing of liquid and during production of 'may/pay', using videofluoroscopy and innovative computer software. We then determined whether soft palate elevation (as reflected in measures of an angle) differed in those separate conditions. Twelve female participants were studied, aged 40-70 years. The trends observed were that the highest soft palate elevation was displayed in the liquid-swallowing condition and the lowest soft palate elevation was displayed in the speech conditions. The results did not reach statistical significance, but the findings support the suggestions of Rubesin et al. (1987) and Fritzell (1969) that soft palate elevation is higher during swallowing than during speech. This same method was then used to measure soft palate elevation under the same three conditions in nine females, all aged >40 years, who had motor neuron disease. Again, the highest soft palate elevation was displayed when swallowing liquid, but this time the lowest elevation occurred when swallowing pudding. Owing to small numbers, results did not reach statistical significance, but the trends may be important to replicate in a larger study. This pilot study developed a comprehensive and accurate method of measuring the soft palate elevation using digitization and computer software.
Taste acuity of the human palate: II. Studies with electrogustometry on subjects in different age groups
Published in Acta Odontologica Scandinavica, 1979
The electrical taste acuity on the hard and soft palate and the tip of the tongue was determined in 140 subjects aged 13-81 years using an electrogustometer constructed for the study. The possible influence of several variables including age, sex, wearing of a full upper denture, smoking as well as medical and social factors on the threshold values was also studied. Taste perception was demonstrated on the soft palate and on an area of the hard palate close to the junction of the hard and soft palate in most subjects. No perception of the electrical taste was found in eleven subjects (8 %) on either the hard or the soft palate and in an additional 33 subjects (24 %) on the hard palate alone and 2 subjects (1 %) on the soft palate alone. The taste thresholds on the hard palate were very high compared to those on the soft palate and those on the tongue. Older subjects generally had higher thresholds than did younger subjects and the differences were greater for the thresholds on the hard and soft palate than for those on the tongue. No statistically significant differences in threshold values were found between women and men, denture wearers and non-denture wearers or smokers and non-smokers.
Related Knowledge Centers
- Bone
- Mouth
- Tissue
- Hard Palate
- Swallowing