THE HEAD AND NECK. 41 



1 . Hozv may the dermal muscles be grouped ? 



They may be grouped about the four apertures : the orbit, the ear, the nose, 

 and the mouth. Their action seems to be secondary to the special senses of 

 hearing, smell, sight, and taste, since they open and close these openings to a 

 variable extent. 



2 . Give the bony attachments of the orbiculans oris. 



This muscle is attached to the upper and also to the lower incisive fossa, and 

 to the alveolar processes. 



3. Has the orbiculans oris any antagonists? If so, name them. 



Yes ; superiorly, levator labii superioris, levator anguli oris, zygomaticus 

 minor, zygomaticus major ; inferiorly, depressor labii inferioris, depressor anguli 

 oris, levator menti, risorius. 



SOCIA PAROTIDIS 



SUBLINGUAL GLAND 



DUCT OF SUBMAXILLARY 



GLAND 

 Mylo-hyoid muscle 



Anterior belly of 

 digastric muscle 



DEEP PORTION OF SUBMAXILLARY GLAND 



FIG. 20. THE SALIVARY GLANDS. 



PAROTID GLAND 



Massetcr muscle 



Ster no -m astoid 

 muscle 



Posterior belly of 

 digastric muscle 



SUBMAXILLARY GLAND. 

 DRAWN BACKWARDS 



Loop of fascia 



4. Name the foramen between the origins of the levator labii superioris and the 

 levator anguli oris. 



The infraorbital, transmitting the infraorbital vessels and nerves. 



5. Locate on a patient the foramen mental c t and tell what it transmits. 



This foramen is located at the junction of the mento-Meckelian and dentary 

 parts of the mandible, one-half of an inch below the gingiva of the second bicuspid 

 tooth ; it transmits the mental branches of the inferior dental vessels and nerves. 



6. What is the function of the mental nerves and with what do they communi- 

 cate ? 



The function is to supply the skin of the lower lip and chin ; they communi- 

 cate with mental branches of the facial nerve. 



7. Name the aural group of dermal muscles, and give their function. 

 Attrahens aurem, attolens aurem, retrahens aurem. These muscles are mere 



vestiges in man, often incapable of demonstration. They are best studied on 

 domestic animals, as the dog and rabbit. Their function is, first, to enlarge the 

 4 



