38 ANATOMY OF THE HEAD AND NECK. 



DISSECTION V. 



SUPERFICIAL CERVICAL REGION. 



The dissection is now transferred to the neck. The head should 

 hang backward by its own weight ; the chain hook should be caught 

 into the septum of the nose, and by it the head should be rotated 

 and held to one side, as far as it is possible to do so; this ex- 

 poses the cervical region, and puts the muscles on the stretch. An 

 incision is made along the median line, from the chin to the sternum, 

 and another, if not already made, along the rainus of the jaw ; a third 

 is carried along the clavicle, from the termination of the first, out- 

 ward. The skin is to be lifted from the angle at the sternum, but as 

 the fibres of the platysma are often very thin and indistinct, and so 

 pale in color as hardly to be distinguished from the fascia between it 

 and the skin, this fascia must be raised with such care as to insure 

 the demonstration of the muscle, however feebly it may be developed. 



The PLATYSMA MYOIDES arises from the integument in 

 front of the thorax, below the clavicle ; its fibres ascend 

 obliquely forward, uniting upon the median line, when well 

 developed, with those of the other side, and are inserted 

 into the chin, the angle of the mouth, and the integument 

 of the face, being intimately connected with, and in fact 

 helping to form several of the facial muscles. 



The platysma is to be removed without disturbing the fascia, or the 

 numerous nerves which lie upon and between it and the sterno- 

 mastoid muscle. 



The removal of the platysma-myoides brings the cervical 

 region more fairly into view. It will be seen that it is 

 quadrilateral, and that its boundaries may be indicated in 

 a general way, as, superiorly, the ramus of the jaw and the 

 mastoid process ; inferiorly, the clavicle ; posteriorly, the 

 edge of the trapezius muscle ; and anteriorly, the median 

 line of the neck. 



The cervical fascia varies in distinctness in different 

 subjects ; it surrounds the neck, and is stronger in front of 

 than behind the stern o-mastoid muscle, which it encases. 

 The external jugular vein lies upon it, and perforates it at 

 its lower part, and the branches of the anterior cervical 

 plexus of nerves lie partly upon and partly beneath the 

 fascia. 



The EXTERNAL JUGULAR YEIN is formed by the union of 

 the posterior auricular and temporo-maxillary veins, veins 

 of the integument and of the zygomatic and pterygoid 

 fossae. The external jugular vein is of variable size; it 



