|Henry Gray (18251861). Anatomy of the Human Body. 1918.|
| The Constrictor pharyngis medius (Middle constrictor) (Figs. 1030, 1031) is a fanshaped muscle, smaller than the preceding. It arises from the whole length of the upper border of the greater cornu of the hyoid bone, from the lesser cornu, and from the stylohyoid ligament. The fibers diverge from their origin: the lower ones descend beneath the Constrictor inferior, the middle fibers pass transversely, and the upper fibers ascend and overlap the Constrictor superior. It is inserted into the posterior median fibrous raphé, blending in the middle line with the muscle of the opposite side.|
FIG. 1030 Muscles of the pharynx and cheek. (See enlarged image)
| The Constrictor pharyngis superior (Superior constrictor) (Fig. 1030, 1031) is a quadrilateral muscle, thinner and paler than the other two. It arises from the lower third of the posterior margin of the medial pterygoid plate and its hamulus, from the pterygomandibular raphé, from the alveolar process of the mandible above the posterior end of the mylohyoid line, and by a few fibers from the side of the tongue. The fibers curve backward to be inserted into the median raphé, being also prolonged by means of an aponeurosis to the pharyngeal spine on the basilar part of the occipital bone. The superior fibers arch beneath the Levator veli palatini and the auditory tube. The interval between the upper border of the muscle and the base of the skull is closed by the pharyngeal aponeurosis, and is known as the sinus of Morgagni.|
| The Stylopharyngeus (Fig. 1019) is a long, slender muscle, cylindrical above, flattened below. It arises from the medial side of the base of the styloid process, passes downward along the side of the pharynx between the Constrictores superior and medius, and spreads out beneath the mucous membrane. Some of its fibers are lost in the Constrictor muscles, while others, joining with the Pharyngopalatinus, are inserted into the posterior border of the thyroid cartilage. The glossopharyngeal nerve runs on the lateral side of this muscle, and crosses over it to reach the tongue.|
| The Salpingopharyngeus (Fig. 1028) arises from the inferior part of the auditory tube near its orifice; it passes downward and blends with the posterior fasciculus of the Pharyngopalatinus.|
Nerves.The Constrictores and Salpingopharyngeus are supplied by branches from the pharyngeal plexus, the Constrictor inferior by additional branches from the external laryngeal and recurrent nerves, and the Stylopharyngeus by the glossopharyngeal nerve.
Actions.When deglutition is about to be performed, the pharynx is drawn upward and dilated in different directions, to receive the food propelled into it from the mouth. The Stylopharyngei, which are much farther removed from one another at their origin than at their insertion, draw the sides of the pharynx upward and lateralward, and so increase its transverse diameter; its breadth in the antero-posterior direction is increased by the larynx and tongue being carried forward in their ascent. As soon as the bolus of food is received in the pharynx, the elevator muscles relax, the pharynx descends, and the Constrictores contract upon the bolus, and convey it downward into the esophagus.
Structure.The pharynx is composed of three coats: mucous, fibrous, and muscular.
| The pharyngeal aponeurosis, or fibrous coat, is situated between the mucous and muscular layers. It is thick above where the muscular fibers are wanting, and is firmly connected to the