Henry Gray (18251861). Anatomy of the Human Body. 1918.
of the epiglottisa movement produced by the contraction of the Thyreoarytænoidei, the Arytænoidei, and the Arytænoepiglottidei.
After leaving the tongue the bolus passes on to the posterior or laryngeal surface of the epiglottis, and glides along this for a certain distance; then the Glossopalatini, the constrictors of the fauces, contract behind it; the palatine velum is slightly raised by the Levator veli palatini, and made tense by the Tensor veli palatini; and the Pharyngopalatini, by their contraction, pull the pharynx upward over the bolus, and come nearly together, the uvula filling up the slight interval between them. By these means the food is prevented from passing into the nasal part of the pharynx; at the same time, the Pharyngopalatini form an inclined plane, directed obliquely downward and backward along the under surface of which the bolus descends into the lower part of the pharynx. The Salpingopharyngei raise the upper and lateral parts of the pharynxi. e., those parts which are above the points where the Stylopharyngei are attached to the pharynx.
Mucous Membrane.The mucous membrane of the soft palate is thin, and covered with stratified squamous epithelium on both surfaces, excepting near the pharyngeal ostium of the auditory tube, where it is columnar and ciliated. According to Klein, the mucous membrane on the nasal surface of the soft palate in the fetus is covered throughout by columnar ciliated epithelium, which subsequently becomes squamous; some anatomists state that it is covered with columnar ciliated epithelium, except at its free margin, throughout life. Beneath the mucous membrane on the oral surface of the soft palate is a considerable amount of adenoid tissue. The palatine glands form a continuous layer on its posterior surface and around the uvula.
Vessels and Nerves.The arteries supplying the palate are the descending palatine branch of the internal maxillary, the ascending palatine branch of the external maxillary, and the palatine branch of the ascending pharyngeal. The veins end chiefly in the pterygoid and tonsillar plexuses. The lymphatic vessels pass to the deep cervical glands. The sensory nerves are derived from the palatine and nasopalatine nerves and from the glossopharyngeal.
2c. The Pharynx
The pharynx is that part of the digestive tube which is placed behind the nasal cavities, mouth, and larynx. It is a musculomembranous tube, somewhat conical in form, with the base upward, and the apex downward, extending from the under surface of the skull to the level of the cricoid cartilage in front, and that of the sixth cervical vertebra behind.
The cavity of the pharynx is about 12.5 cm. long, and broader in the transverse than in the antero-posterior diameter. Its greatest breadth is immediately below the base of the skull, where it projects on either side, behind the pharyngeal ostium of the auditory tube, as the pharyngeal recess (fossa of Rosenmüller); its narrowest point is at its termination in the esophagus. It is limited, above, by the body of the sphenoid and basilar part of the occipital bone; below, it is continuous with the esophagus; posteriorly, it is connected by loose areolar tissue with the cervical portion of the vertebral column, and the prevertebral fascia covering the Longus colli and Longus capitis muscles; anteriorly, it is incomplete, and is attached in succession to the medial pterygoid plate, pterygomandibular raphé, mandible, tongue, hyoid bone, and thyroid and cricoid cartilages; laterally, it is connected to the styloid processes and their muscles, and is in contact with the common and internal carotid arteries, the internal jugular veins, the glossopharyngeal, vagus, and hypoglossal nerves, and the sympathetic trunks, and above with small parts of the Pterygoidei interni. Seven cavities communicate with it, viz., the two nasal cavities, the two tympanic cavities, the mouth, the larynx, and the esophagus. The cavity of the pharynx may be subdivided from above downward into three parts: nasal, oral, and laryngeal(Fig. 994).
The Nasal Part of the Pharynx (pars nasalis pharyngis; nasopharynx) lies behind the nose and above the level of the soft palate: it differs from the oral and laryngeal parts of the pharynx in that its cavity always remains patent. In front (Fig. 1029) it communicates through the choanæ with the nasal cavities. On its lateral wall is the pharyngeal ostium of the auditory tube, somewhat triangular in shape, and bounded behind by a firm prominence, the torus or cushion, caused by the medial end of the cartilage of the tube which elevates the mucous membrane.