i28 APPLIED ANATOMY. 



seven, no matter what the length of the neck. From a consideration of these facts 

 we may perhaps state that the neck itself is a subsidiary organ, not of any great im- 

 portance in itself, but rather in relation to some other portion of the body that 

 portion being the head. It is the staff which supports the head by means of the 

 cervical spine and muscles. 



The neck contains the great currents of blood which pass to and fro between 

 the head and trunk. It carries the air- and food-passages, which run from the mouth 

 above to the lungs and stomach below, and incidentally it contains the larynx, the 

 thyroid and submaxillary glands, and some lymphatic nodes. The cerebrospinal 

 nerves of all the body below the head pass either into the neck or through it to the 

 parts beyond. From these facts it becomes evident that, while the neck in itself may 

 be a subsidiary organ, for our purposes it is of the greatest importance, because 

 interference with its structure either by disease or injury operative or accidental 

 may destroy the brain above, by interfering with its nourishment, or the body below, 

 by interfering with the vital functions of respiration and nutrition, or may paralyze it 

 by destroying the conductivity of its nerves. The construction of the neck then 

 should be studied with a view of explaining or understanding the diseases and injuries 

 of its various parts and the operations performed for their relief. 



Injuries and Diseases of the Neck. Owing to its exposed position the 

 neck is frequently injured by sprains, contusions, cuts, and punctured, gunshot, and 

 all sorts of wounds. The cervical spine may become dislocated or fractured and is 

 frequently the seat of caries. The muscles become contracted, producing torticollis 

 or wry-neck. They may sometimes be ruptured, as in childbirth. 



The arteries are affected with aneurism, necessitating their ligation. They are 

 also divided in cut-throat cases and wounds. The veins are of importance in almost 

 every operation; bleeding from them is dangerous and may be difficult to control. 



The lymphatic nodes are more numerous than elsewhere in the body. Frequently 

 they are the seat of tuberculous or sarcomatous enlargement, necessitating their re- 

 moval. They may break down and produce wide-spreading and dangerous abscesses, 

 which are guided in their course by the fascias ; hence a knowledge of the construc- 

 tion of the deep fascias of the neck enables us to understand them. 



The siibmaxillary and thyroid glands are the seat of enlargement and foreign 

 growths requiring the performance of extensive operations for their extirpation. 

 Enlargement of the thyroid gland constitutes the disease known as goitre. It is also 

 involved in exophthalmic goitre or Graves' s or Basedow 1 s disease. 



The skin and siibcutaneous tissue become the seat of inflammation and cellulitis. 

 In cases of wounds this cellular inflammation may involve the structures beneath the 

 deep fascia; this occurs in cut-throat and gunshot wounds. 



The neck is also liable to other affections, such as cysts due to embryological 

 defects. Large cysts are formed called hygromas, also sinuses or fistulae, the con- 

 genital fistulce of the neck. The larynx may be the seat of malignant disease; hence 

 its removal is undertaken. The operations of tracheotomy, laryngotomy, and cesoph- 

 agotomy are also at times necessary. In order to understand these various affec- 

 tions and procedures one must be familiar with the construction of the neck, what 

 composes it, where the various structures lie and their relation to one another. In 

 order to utilize this knowledge we must be able to recognize and identify the 

 position of various structures before the skin is incised, for it is rarely that a case 

 presents itself with a wound that permits a view of the deeper structures; hence the 

 importance of a thorough knowledge of its surface and the structures capable of 

 being recognized through the skin. 



SURFACE ANATOMY OF THE NECK. 



For convenience of study we may consider the structures in the median line, 

 and those regions anterior and those posterior to the sternomastoid muscle, between 

 it and the trapezius. The posterior portion of the neck will be described in the 

 section devoted to the back. 



These regions or triangles are simply arbitrary divisions, made for conveni- 

 ence of description. They are sometimes spoken of in reference to the location 



