482 MUSCLES OF ANTERIOR ISTECK. 



the neck. This brings to view the superficial fascia, the 

 removal of which exposes the first superficial muscle. 



The platysma myoides, (7tta*uj, ^vj, &>$, broad muscle-like 

 lamella) or latissimus colli, consists of a very delicate, thin, 

 pale, and broad plane of muscular fibres, situated between 

 two layers of the superficial fascia. It is a cutaneous 

 muscle corresponding to the panniculus carnosus of quad- 

 rupeds. 



It arises below the clavicle from the cellular tissue and 

 integument covering the pectoral and deltoid muscles, and 

 then ascends obliquely inward upon the side of the neck, 

 to be inserted into the cellular tissue and skin of the chin, 

 where it intersects fibres from the opposite side, and into 

 the fascia of the lower jaw. Its fibres are frequently traced 

 upward, intermingling with the muscles at the angle of the 

 mouth, and backward to the fascia covering the parotid 

 gland. From this gland a transverse band of fibres, riso- 

 rius santorini, have been traced to the angles of the mouth. 



Function. To depress the lower jaw and angles of the 

 mouth, and if the mouth be closed to raise the skin upon 

 the neck. It covers and supports the muscles, vessels and 

 glands beneath, and has the external jugular vein partly 

 imbedded in its substance. 



Sterno-cleido mastoideus (Fig. 146) is situated at the lat- 

 eral and anterior part of the neck, enclosed between two 

 layers of the cervical fascia. It arises from the sternum 

 by a strong flat tendon, and from the sternal third or 

 half of the clavicle by a broad, fleshy and aponeurotic ori- 

 gin. These two origins of this muscle include a small 

 space of triangular shape, containing small vessels and cel- 

 lular substance. The sternal portion is the larger, and as 

 it ascends, overlaps the clavicular which proceeds verti- 

 cally. About tlie middle of the neck the two are united, 

 and thence go to be inserted into the mastoid process by a 

 thick, round tendon, and by an aponeurosis into the outer 

 portion of the superior transverse ridge of the occipital 

 bone. 



Function. Both muscles acting together will bend the 





