Skull and Hyoid 



257 



pharyngeal structures. Thus at its origin it is in contact with the internal pterygoid 

 plate and the Tensor palati behind this (Fig. 205), which separates it from the sinus 

 of Morgagni and the structures passing through this : below these it is in direct relation 

 with the upper Constrictor and, a little lower, with the muscles running on the Con- 

 strictor to the pharyngeal wall, i.e., Stylo-glossus and (deeper) Stylo-pharyngeus : 

 near the angle it is in contact with the submaxillary gland, which with the head in the 

 natural position separates it from Digastric and Stylo-hyoid, and from the external 

 carotid artery where this turns upwards, outwards and backwards from the wall of 

 the pharynx, along the Stylo-hyoid. 



The insertion of the Internal Pterygoid (Fig. 204) is by mixed muscular and 



spfne of 

 Sffienoid 



Tensor 



'ong inf. 

 l*t. Kg. 



-Stylo -gloss. 

 %/<? -phir. 



FIG. 205. To show the deep relations of the lower jaw and its muscles. The 

 pharynx, with the jaw in position, is seen from behind. On the right the 

 Digastric, Stylo-hyoid, Stylo-pharyngeus, and Stylo-glossus are cut short : 

 on the left the last two muscles are turned back, and the submaxillary 

 gland is shown between the internal pterygoid and Digastric and Stylo- 

 hyoid, and above them. The parotid, with a quantity of loose tissue, 

 occupies the interval above and behind the Pterygoideus internus. 



tendinous fibres, as can be inferred from the roughnesses in its area : it extends high 

 along the back part of the inner surface of the ramus, nearly reaching the neck, and here 

 the parotid turns round the back of the bone and comes into relation with its inner 

 aspect. The fibres of the muscle pass upwards, forwards and inwards to their origin, 

 so that a rapidly-increasing interval occurs between them and the ramus. In the top 

 of this interval the External Pterygoid separates the inner muscle from the plane 

 of the jaw, and below this the bone has in relation with it, and between it and the 

 Internal Pterygoid, the internal maxillary artery and some of its branches, the lingual 

 and inferior dental nerves, the internal lateral ligament, the mylo-hyoid nerve and 

 vessels, and frequently a small process of the parotid gland (Fig. 204). 



The small masseteric artery runs to the coronoid notch between the bone and the 



F.A. 17 



