180 PLATYSMA MYOIDES. 



3. Elevators of tJte os 6. Muscles of the soft Palate. 



hyoides and larynx. 



Digastricus, Tensor palati, 



Stylo-hyoideus, Azygos uvulae, 



Mylo-hyoideus, Palato-glossus, 



Genio-hyoideus, Palato-pharyngeus. 



Genio-hyo-glossus. 



7. Prcevertebral Group. 

 4. Muscles of tJie Tongue. 



. , , Rectus anticus major, 



Genio-hyo-glossus, 



Hyo-glossus, 



Scalenus posticus, 

 Stylo-glossus, L C UL 



Palato-glossus. 



5. Muscles of the Pharynx. 8 - Musdes of the Larynx. 



Constrictor inferior, Crico-thyroideus, 



Constrictor medius, Crico-arytaenoideus, posticus, 



Constrictor superior, Crico-arytsenoideus, lateralis, 



Stylo-pharyngeus, Thyro-arytsenoideus, 



Palato-pharyngeus. Arytaenoideus. 



Dissection. The dissection of the neck should be commenced by 

 making an incision along the middle line of its fore part from the chin 

 to the sternum, and bounding it superiorly and inferiorly by two 

 transverse incisions ; the superior one being carried along the margin 

 of the lower jaw, and across the mastoid process to the tubercle on 

 the occipital bone, the inferior one along the clavicle to the acromion 

 process. The square flap of integument thus included should be turned 

 back from the entire side of the neck, which brings into view the 

 superficial fascia, and on the removal of a thin layer of superficial fascia 

 the platysma myoides will be exposed. 



The PLATYSMA MYOIDES (wA.a<rvs, pv$ sl^aj, broad muscle-like la- 

 mella), is a thin plane of muscular fibres, situated between the two 

 layers of the superficial cervical fascia ; it arises from the integument 

 over the pectoralis major and deltoid muscles, and passes obliquely 

 upwards and inwards along the side of the neck to be inserted into the 

 side of the chin, oblique line of the lower jaw, the angle of the mouth, 

 and into the cellular tissue of the face. The most anterior fibres are 

 continuous beneath the chin, with the muscle of the opposite side ; 

 the next interlace with the depressor anguli oris, and depressor labii 

 inferioris, and the most posterior fibres are disposed in a transverse 

 direction across the side of the face, arising in the cellular tissue 

 covering the parotid gland, and inserted into the angle of the mouth, 

 constituting the risorius Santorini. The entire muscle is analogous 

 to the cutaneous muscle of brutes, the panniculus carnosus. 



Relations. By its external surface with the integument, with which 

 it is closely adherent below, but loosely above. By its internal surface, 



