THE HEAD, ANTERIOR. 59 



The fasciae and platysma and its facial portion, the risorius, are all to be 

 studied and then removed, and the facial muscles above then below the mouth 

 are to be cleaned. Along with the dissection of the muscles will proceed the 

 cleaning of the nerves, veins (facial especially), and the arteries. 



Risorius. 



This is a thin sheet of loosely joined muscular fibres, an 

 extension and derivation of the platysma, which extends from 

 the masseteric and parotid fasciae to the angle of the mouth. 

 The Masseteric and Parotid Fasciae. 



The upward continuation of the superficial layer of the 

 deep cervical fascia from the neck over the masseter muscle 

 and parotid gland is called the masseteric and parotid fascia 

 respectively. See page 138. 



The former is attached, above, to the lower border of the 

 zygomatic arch, and below, to the lower and posterior bor- 

 ders of the lower jaw. An extension of this fascia from the 

 angle of the jaw to the styloid process is called the stylo- 

 maxillary ligament. It serves to separate the parotid from 

 the submaxillary gland. 



The latter (parotid) fascia covers in the parotid gland. In 

 front it is continuous with the masseteric fascia ; above, 

 attached to the zygomatic arch ; behind, to the front of the 

 mastoid process, and below, extends into the cervical fascia. 

 Zyg-omaticus Major. Fig. 3. 



Origin. From the outer surface of the malar bone. 



Insertion. Into the orbicularis oris, levator anguli oris, 

 and skin at the angle of the mouth. 



Nerve Supply. The seventh or facial by its infra-orbital 

 branch. 



Action. To raise and retract the angle of the mouth. 

 Zygomaticus Minor. 



Origin. The lower part of the anterior surface of the 

 malar bone. 



