THE XOSI-: AM) XFX'K 1091) 



portion of the inferior tur))inated Ijonc can be seen. On throwing: the head further 

 back, witli a good light the lower margin of the middle turl)inatcd bone can also l)e 

 made out. This is much higlier uj) and nearly on a level with the ro(tt of the nasal 

 bone. The septum often deviates to one side. The mucous membrane over it is, 

 in health, dull red in colour; that over the inferior turbinated is thicker. The 

 anterior extremity of the latter l)one is about three-cjuarters of an inch behind tlie 

 orifice, while the opening of the nasal duct is about one inch ))ehiii<l and about 

 three-quarters of an inch al)ove the fioor. The (»pening into the antrum is situated 

 in al)out the centre of the middle meatus and one incli al)ove the llo<tr. 



The j)osterior nares should be examined by the finger passed behind the soft 

 palate. Each oval aperture measures, in the adult skull, al>out half an inch trans- 

 versely by one vertically. In life the al)ove dimensions are somewhat less, owing to 

 the presence of the mucous membrane. The l)oundaries of these apertures should 

 be identified, viz. : internally, the vomer; externally, the internal pterygoid ))late 

 and palate V)one; above, tlie basisphenoid; and Ijelow, the ])osterior lionler of the 

 horizontal plates of the palate bones and posterior nasal spine. 



THE NECK 



Landmarks in the middle line. — Passing from the symphysis to the sujtra- 

 clavicular notch is the body of the hyoid, which is nearly on a level with 

 the angles of the jaw. On either side of the body are the great cornua. The upjjcr 

 borders of these are the guides to the lingual arteries. Below the hyoid is the thyro- 

 hyoid space, which corresponds with the epiglottis and the upper aperture of the 

 larynx. Thus, if the throat be cut aljove the hyoid, the mouth will be ojtened and 

 the tongue cut into; if the thyro-hyoid space be cut, the pharynx would be ojiened 

 and the epiglottis wounded near its base. Behind the centre of the anterior margin 

 of the thyroid is the rima glottidis. The projection of the thyroid notcli is much 

 more distinct in men than in women or children. It does not ai)i)ear liefore puberty, 

 and thus flatness of the thyroid must be expected when the landmarks for traehe- 

 otomy are sought for in children with short fat necks. The cricoid, on the other 

 hand, is always to be made out. It corresponds in horizontal i>lane to the folknv- 

 ing: — (1) The fifth cervical vertebra. (2) The junction of pharynx and asopha- 

 gus: from the narrowing of the tube here, foreign bodies may lodge at this ])oint 

 and cause dyspnoea by pressing on the air-tube in front. The cricoid is taken as 

 the centre of the incision in cesophagotomy, and also for ligature of the common 

 carotid. (3) The junction of larynx and trachea. (4) The crossing of the omo- 

 hyoid over the common carotid. (5) The middle cervical ganglion. 



The distance between the cricoid and the manubrium is only about an inch and 

 a half. When the neck is stretched, about three-quarters of an inch more is gained. 

 Thus, as a rule, there are not more than seven or eight tracheal rings al)ove tlie 

 sternum. Of these, the second, third, and fourth are covered by the thyr(»id ii^th- 

 mus. The parts met with in the middle line — ('0 above, and (/>) below the isth- 

 mus — should be borne in mind: (a) Skin, su]»erficial fascia, branches of transverse 

 cervical and infra-mandilndar nerves, lym])hatics. cutaneous arteries, anterior jug- 

 ular veins — with their transverse branches smaller above. — deep fascia, sterno- 

 hvoids, cellular ti.ssue, sujierior thyroid vessels, and tracheal layer of dceit fascia. 

 The importance of this last is two-fold, as, first, the tuln' in tradieotomy may be 

 passed between it and the trachea, and after a wound in this region this layer, con- 

 tinuous with the pericardium, may conduct discharges into the mediastina. (h) 

 The surface structures are much the same, but the anterior jugular veins and their 

 transverse branches are much larger. The inferior thyroid veins are also larger. 

 A thyroidea ima may be present, and the innominate artery, which often cr(».<.<es 

 the trachea above the sterno-davicular joint, may do so as high as the seventli tra- 

 cheal ring. The trachea is also smaller, deeper, and less stea(He<l by muscles. Tiie 

 thymus, too, in young children, may prove a difficulty. Thus, in cliildren, the 

 high operation, incising thi^ cricoid and crico-traciieal membrane, if needful, is to 

 be ]irefcrrc(l. 



The sterno-mastoid is the landmark for several important operations. Its 



