22 HEAD AND NECK 



accumulating between the cheeks and the teeth, the con- 

 tractions of the muscle forcing the food back, between the 

 teeth, into the cavity of the mouth proper. It is also used 

 for blowing and whistling. It is supplied by the facial nerve. 

 The Molar Glands. The pad of fat which covered the 

 buccinator posteriorly, and which was removed, as the buccal 

 branch of the mandibular nerve was cleaned, is known as the 

 corpus adiposum buccae, or suctorial pad. Its removal 

 exposed the bucco-pharyngeal fascia and a number of small 

 glands, called the molar salivary glands. The ducts of the 

 molar glands pierce the buccinator and open into the vestibule 

 of the mouth. One or two buccal lymph glands also are 

 sometimes found resting on the superficial surface of the 

 buccinator. 



Dissection. After the dissection of the buccinator and the 

 molar glands is completed, remove the stitches from the lips ; 

 evert the lips and dissect the mucous membrane from the deep 

 surfaces, in order to expose the muscular slips which attach the 

 orbicularis oris to the alveolar margins of the maxilla and the 

 mandible, and to display the mentalis muscle. As the lips are 

 everted the dissector should note that a fold of mucous membrane, 

 the frenulum labii, passes from each lip to the adjacent gum in 

 the median plane ; and as the mucous membrane is removed a 

 number of small labial salivary glands, which lie in the sub- 

 mucous tissue, will be seen. They are readily felt in the living 

 subject when the tip of the tongue is pressed against the inner 

 surfaces of the lips. 



Mnsculi Incisivi Labii Superioris et Inferioris. The 

 incisive muscles of the upper and lower lips are four small 

 muscular bundles, two upper and two lower, which attach 

 the deeper part of the orbicularis oris to the alveolar margins 

 of the maxillae and mandible in the regions of the upper and 

 lower lateral incisor teeth. 



Musculus Mentalis. When the incisive muscles of the 

 mandible are detached from the bone and the lower lip is 

 further everted, a distinct muscular bundle will be found on 

 each side, springing from the outer surface of the socket of the 

 canine tooth, under cover of the quadratus labii inferioris. 

 The two bundles converge and blend together, between the 

 medial borders of the musculi quadrati labii inferioris, to 

 form a single bundle which is inserted into the skin of the 

 chin. It is an elevator of the skin of the chin. It is sup- 

 plied by the facial nerve. 



Nervus Buccinatorius (O.T. Long Buccal). The buccinator 



