FORE PART OF NECK. 67 



towards the clavicle over the lower part of the triangular space. Their 

 number is somewhat uncertain, but usually there are about three on the 

 clavicle. 



The most internal branch (sternal) crosses the clavicle near its inner 

 end ; the middle branch lies about the middle of that bone ; and the 

 posterior (acromial) turns over the attachment of the trapezius to the 

 avromion. All are distributed in the integuments of the chest and shoulder. 



Derived from the descending set are two or more posterior cutaneous 

 cervical nerves, which ramify in the integument over the lower two thirds 

 of the fore part of the trapezius. 



The lymphatic glands (glandulae concatenate) lie along the sterno- 

 mastoid muscle, and are continuous at the lower part of the neck with the 

 glands in the cavity of the thorax. There is also a superficial chain along 

 the external jugular vein. 



Dissection. The dissection of the posterior triangle should be repeated 

 on the left side of the neck, in order that the difference in the vessels may 

 be observed. Afterwards the reflected parts are to be replaced and care- 

 fully fastened in their natural position with a few stitches, preservative 

 fluid or salt having been previously applied. 



Directions. It is supposed that the body will now be turned on the fore 

 part for the examination of the Back ; and during the time allotted for 

 this position the dissector of the head is to learn the posterior part of the 

 neck. (DISSECTION OF THE BACK.) 



After the completion of the Back, the student should take out the spinal 

 cord, and then return to the dissection of the front of the neck, which is 

 described below. 



FRONT OF THE NECK. 



Directions. Supposing the thorax and Back finished, the head and 

 neck may be detached from the trunk by dividing the spinal column be- 

 tween the second and third dorsal vertebrae, and cutting through the arch 

 of the aorta beyond its large branches (if this is not done), so as to take 

 that piece of the vessel with the head. The dissector continues his work 

 on the remainder of the right side of the neck ; but if the facial nerve 

 has been omitted, it should be first learnt (p. 47). 



Position. Supposing the facial nerve completed, a small narrow block 

 is to be placed beneath the left side of the neck, and the face is to be 

 turned from the dissector. Further, the neck is to be made tense by 

 means of hooks, the chin being well raised at the same time. 



Dissection. An incision along the base of the jaw on the right side (if 

 it has not been made already) will readily allow the piece of integument 

 in front of the sterno-mastoideus to be raised towards the middle line. 

 Beneath the skin is the superficial fascia, containing very fine offsets of 

 the superficial cervical nerve. 



To define the platysma muscle, remove the fat which covers it, carrying 

 the knife down and back in the direction of the fleshy fibres. 



PLATYSMA MYOIDES. The anterior part of the platysma, viz., from 

 the sterno-mastoid muscle to the lower jaw, covers the greater portion of 

 the anterior triangular space. At the base of the jaw it is inserted be- 

 tween the symphysis and the masseter muscle ; while other and more 

 posterior fibres are continued over the face, joining the depressor anguli 



