THE MUSCLES OF THE PHAKYNX. 



465 



The superior fibres overlap the inferior part of the superior constrictor ; the 

 j inferior fibres are concealed from view by the inferior constrictor muscle. In the 

 (interval between the middle" and inferior constrictors are found the superior 

 laryngeal artery and internal laryngeal nerve. 



M. Constrictor Pharyngis Inferior. The inferior constrictor muscle arises 

 from the oblique line of the thyreoid cartilage (thyreopharyngeus), and from 

 the side of the cricoid cartilage (cricopharyngeus). 



Its fibres radiate backwards, to be inserted into the median raplie on the 

 posterior wall of the pharynx, the superior fibres overlapping the inferior part of 

 the middle constrictor, the inferior fibres blending with the muscular fibres of the 

 O3sophagus. Below the inferior border of the muscle the inferior laryngeal artery 

 and nerve enter into relation with the larynx. 



Nerve-Supply. The constrictors of the pharynx receive their nerve-supply through the 

 pharyngeal plexus from the accessory nerve. 



The inferior constrictor is supplied also Pharyngo-basiiar fascia 



by the external laryngeal and recurrent 

 branches of the vagus nerve. 



The deeper longitudinal stratum 

 of muscles in the pharyngeal wall 

 is composed of the insertions of the 

 stylopharyngeus and pharyngopala- 

 tinus muscles. 



M. Stylopharyngeus. The stylo- 

 pharyngeus arises from the root of 

 the styloid process on its medial side, 

 and passes downwards between the 

 external and internal carotid arteries. 

 It enters the wall of the pharynx in 

 the interval between the superior 

 and middle constrictor muscles. 



Spreading out beneath the middle 

 I constrictor muscle, it is inserted into 

 the superior and posterior borders of 

 the thyreoid cartilage and into the 

 wall of the pharynx itself, becoming 

 continuous posteriorly with the palato- 

 pharyngeus. In the neck the glosso- 

 pharyngeal nerve winds round it on 

 its way to the tongue. 



Nerve-Supply. Glossopharyngeal 



nerve. (Esophagus (with posterior 



ends of tracheal rings 

 showing at the sides) 



Auditory tube 



LEVATOR VELI 

 PALATINI 



MUSCLE (CUt) 



TENSOR VELI 



PALATINI 



SUPERIOR 

 CONSTRICTOR 

 BUCCINATOR 



Pterygo-mandi- 

 bular raphe 



STYLO- 

 PHARYNGEUS 



MIDDLE 

 CONSTRICTOR 



Greater cprnu of 

 hyoid bone 



INFERIOR CONSTRICTOR 



FIG. 412. POSTERIOR VIEW OF THE PHARYNX AND 

 CONSTRICTOR MUSCLES. 



M. Pharyngopalatinus. The 

 pharyngopalatinus (O.T. palato- 

 pharyngeus) occupies the soft palate 

 and the pharyngeal wall. In the 

 substance of the soft palate it consists of two layers, a postero-superior layer, thin, 

 and continuous across the median plane with the corresponding layer on the 

 opposite side, and an antero-inferior layer, which is thicker, and is attached to 

 the posterior border of the hard palate. The levator veli palatini and the musculus 

 uvulae are enclosed between the two layers, which unite at the posterior edge of 

 the palate, receiving at the same time additional fibres arising from the auditory 

 tube (salpingopharyngeus). The muscle descends to the pharynx in the 

 pharyngo-palatine arch. 



Its fibres spread out in the form of a thin sheet in the wall of the pharynx, 



continuity anteriorly with the stylopharyngeus, and are inserted into the 



terior border of the thyreoid cartilage, and behind that into the aponeurosis of 



the pharynx, reaching down as far as the inferior border of the inferior constrictor. 



The muscle is placed beneath the middle and inferior constrictors, and the fibres 



31 



