FRONT OF THE NECK. r>79 



that bone ; and the external (acromial) turns over the clavicular 

 attachment of the trapezins to the acromion. All are distributed 

 to the skin of the chest and shoulder. 



Derived from the descending set are one or two posterior cutaneous Posterior 

 nerres of the necl\ which ramify in the integument covering the cutaneous. 

 trapezins above the scapula. 



The lymphatic glands lying along the sterno-mastoid (glandulse Lymphatic 



concatenate^) are some of the deep cervical glands, and are continuous f, s ' 

 through the lower part of the posterior triangular space with the 

 glands of the axilla. A chain of superficial cervical glands accom- 

 panies the external jugular vein ; and close to the skull, over the 

 apex of the posterior triangular space, are one or two small sub- 

 occipital glands ; while farther forwards, resting on the insertion of 

 the sterno-mastoid, there are two or three small mastoid glands. 



FRONT OF THE NECK. 



Directions. Having displayed the chief structuies in the 

 posterior triangle, the student will expose those in the anterior. 



Dissection. The skin over the front of the neck is to be turned 

 forwards to the middle line. Beneath the skin is the superficial TO raise 

 fat, containing very fine offsets of the superficial cervical nerve. skin 



To define the platysma muscle, remove the fat which covers it, to show 

 carrying the knife downwards and backwards in the direction of P lat J' sma - 

 the neshy fibres. 



PLATYSMA MYOIDES. The anterior part of the platysma^ viz., Anterior 

 from the sterno-mastoid muscle to the lower jaw, covers the greater ^tvsma 

 portion of the anterior triangular space. At the base of the jaw it inse rtion 

 is inserted between the symphysis and the masseter muscle ; while into jaw. 

 other and more posterior fibres are continued over the face, joining 

 the depressor anguli oris and risorius, as far as the fascia covering 

 the parotid gland, or even to the cheek-bone. 



The fibres have the same appearance in this as in the posterior crossing of 

 half of the muscle, but they are rather stronger. Below the chin the fibres - 

 the inner fibres of opposite muscles frequently cross for a short 

 distance, but those of them which are superficial do not always 

 belong to the same side in different bodies. 



Action. The hinder part of this muscle draws the corner of the Use on 

 mouth downwards and outwards ; the fore part is used in swallow- moutl1 

 ing, and carries forwards the skin of the upper part of the neck, l ^ v<s 

 thus facilitating the upward movement of the larynx. When the 

 muscle contracts forcibly, the skin of the upper part of the chest and 

 shoulder is also raised. 



Dissection. Raise the platysma to the base of the jaw, and Dissectioc. 

 dissect out beneath it the branches of the superficial cervical nerve, 

 and the cervical branch of the facial nerve. Clean also the deep 

 fascia of the neck, and the anterior jugular vein which is placed near 

 the middle line. 



The SUPERFICIAL CERVICAL NERVE has just been traced from its Superficial 

 origin in the cervical plexus to its position on the deep fascia of the 



PP 2 



