THE MOUTH. 



40£ 



They may be studied in the following order : 1. Fibrous membrane. 2. Muscles. 

 3. Mucous membranes. 4. Vessels and nerves. 



1. Fibrous membrane (Fig. 215, 5). — This membrane, remarkable for its 

 power of resistance, forms a real framework for the soft palate, of which it only 

 occupies the anterior moiety. It is attached in front of the palatine arch, and is 

 prolonged posteriorly by a particular muscle, the palato-pharyngeus, 



2. Muscles. — Of these muscles, which are all pairs, there are those which 

 constitute a layer situated in the middle of the soft palate itself, and represent 

 the intrinsic muscles ; these are the pharyngo-staphyUnus {palato-pharyngeus) 

 and the palato-staphyUnus {circumfiexus palati). The others, the j^^^^staphylvius 

 — external and internal (tensors palati external and internal)^ are only inserted 



Fig. 224. 



MEDIAN LONGITUDINAL SECTION OF THE HEAD AND UPPER PART OF NECK. 



1, Upper lip ; 2, premaxilla ; 3, hard palate ; 4, tongue ; 5, septum nasi ; 6, nasal bone ; 7, palatine 

 arch; 9, pterygoid bone; 10, epiglottis; 11, entrance to the Eustachian tube; 12, arytenoid 

 cartilage; 13, cricoid cartilage; 14, oesophagus; 15, frontal bone and sinus; 16, cerebrum; 

 17, corpus callosum ; 18, cerebellum; 19, sphenoid bone; 20, medulla oblongata; 21, cervical 

 ligament ; 22, spinal cord ; 23, occipital bone ; 24, 24, atlas ; 25, 25, dentata ; 26, trachea. 



into the organ by their terminal extremities, and therefore act as extrinsic 

 muscles. 



Pharyngo-staphylinus (Palato-phar3mgeus) (Fig. 215, 6) 



In removing the mucous and glandular layers which cover the anterior face 

 of the soft palate, there is exposed a wide and thin muscular fasciculus succeed- 

 ing the fibrous layer behind, and occupying the posterior half of the entire 

 organ. The fibres of which this muscle is composed, mixed in the median line 

 with those of the muscle of the opposite side, are directed backwards and 

 outwards, the most posterior following the curve of the free border of the 

 curtain. Arriving near the lateral border, they are reflected upwards, passing 

 between the pharyngeal mucous membrane and the middle constrictor of the 

 pharynx, with which it appears to be confounded posteriorly ; but with a little 

 attention it can be followed to the superior border of the thyroid cartilage, into 



