TONSILS. PAROTID GLAND. 561 



submaxillary gland, and several smaller openings, the ducts of the sub- 

 lingual gland. 



The Soft palate (velum pendulum palati) is a fold of mucous mem- 

 brane situated at the posterior part of the mouth. It is continuous, 

 superiorly, with the hard palate, and is composed of mucous membrane, 

 palatal glands, and muscles. Hanging from the middle of its inferior 

 border is a small rounded process, the uvula ; and passing outwards 

 from the uvula on each side are two curved folds of the mucous mem- 

 brane, the arches, or pillars of the palate. The anterior pillar is con- 

 tinued downwards to the side of the base of the tongue, and is formed 

 by the projection of the palato-glossus muscle. The posterior pillar is 

 prolonged downwards and backwards into the pharynx, and is formed 

 by the convexity of the palato-pharyngeus muscle. These two pillars, 

 closely united above, are separated below by a triangular interval or 

 niche, in which the tonsil is lodged. 



The Tonsils (amygdalae) are two glandular organs, shaped like 

 almonds, and situated between the anterior and posterior pillar of the 

 soft palate, on each side of the fauces. They are cellular in texture, 

 and composed of an assemblage of mucous follicles, which open upon 

 the surface of the gland. Externally, they are invested by the 

 pharyngeal fascia, which separates them from the superior constrictor 

 muscle and internal carotid artery, and prevents an abscess from open- 

 ing in that direction. In relation to surrounding parts, they correspond 

 with the angle of the lower jaw. 



The space included between the soft palate and the root of the 

 tongue is the isthmus of the fauces. It is bounded above by the soft 

 palate ; on each side by the pillars of the soft palate and tonsils ; and 

 below by the root of the tongue. It is the opening between the mouth 

 and pharynx. 



SALIVARY GLANDS. 



Communicating with the mouth are the excretory ducts of three 

 pairs of salivary glands, the parotid, submaxillary, and sublingual. 



The Parotid gland (ira^a,, near, ov j, u ros , the ear,) the largest of the 

 three, is situated immediately in front of the external ear, and extends 

 superficially for a short distance over the masseter muscle, and deeply 

 behind the ramus of the lower jaw. It reaches inferiorly to below the 

 level of the angle of the lower jaw, and posteriorly to the mastoid 

 process, slightly overlapping the insertion of the sterno-mastoid muscle. 

 Embedded in its substance are the external carotid artery, temporo- 

 maxillary vein, and facial nerve ; emerging from its anterior border, 

 the transverse facial artery and branches of the pes anserinus ; and 

 above, the temporal artery. 



The duct of the parotid gland (Stenon's* duct) commences at the 



* Nicholas Stenon, an anatomist of great research. He discovered the paro- 

 tid duct while in Paris. He was appointed professor of Medicine in Copen- 



2 O 



