1354 CLINICAL AND TOPOGRAPHICAL ANATOMY 



About 1.2 cm. (| in.) behind the posterior extremities of the inferior conchse, 

 just above the level of the hard palate (fig. 1097), on the side of the naso-pharynx, 

 are the openmgs of the tuhce auditivce (Eustachian tubes). Oval in shape, these 

 are bounded above and behind by the prominence of the cartilage, which is want- 

 ing below, thus facilitating the entry of a catheter. The lower part of the tube 

 contains in early life IjTnphoid tissue; enlargement of this explains the deafness 

 in certain cases of adenoids. At the upper part of the naso-pharynx, on the 

 posterior wall, extending doT\Ti laterally as far as the tubse auditivse, is the col- 

 lection of lymphoid tissue known as the pharyngeal tonsil, which when hypertro- 

 phied, pla}' s a large part in 'naso-pharyngeal adenoids.' From the periosteum 

 of the basi-sphenoid and basi-occipital arise naso-pharyngeal fibromata. 



Nasal septum. — The structure of the skeletal element of the septum, which 

 consists of the septal cartilage, the vertical plate of the ethmoid and the vomer, 

 is shouTi in fig. 1099. Slight deviations of the septum to one side are common 

 in adults, and involve mainly the cartilage and the ethmoid bone, the vomer 

 being but little affected as a rule. 



The convexity is most commonly on the right side, and occlusion of the nares on that side 

 with unsightly deflection of the whole nose, results in some cases during the transition from the 

 nfantile to the adult facial conformation. Too extensive removal of the bony septum in the 

 operation of submucous resection for the relief of this condition may cause sinking in of the 

 bridge of the nose. More often, however, this is due to the destructive effect of congenital 

 syphilis. 



Accessory sinuses. — The communication of these air sinuses with the nasal 

 fossse are of great clinical importance. The sphenoidal sinus opens high up into 

 the spheno-ethmoidal recess. The posterior ethmoidal sinuses open into the 

 superior meatus under cover of the superior concha. The infundibulum of the 

 frontal sinus, the anterior and middle ethmoidal and the maxillary sinus all 

 communicate with the middle meatus under cover of the middle concha. The 

 orifice of the maxillary sinus lies at the lowest part of the hiatus semilunaris 

 into the front and upper end of which the frontal sinus opens. Consequently 

 infected fluid may trickle down from the latter into the maxillary sinus. The 

 orifice of this sinus is placed high up in its medial wall so that fluid does not 

 drain away from it readily in case of infection. When the head is held forward 

 in a stooping position some of the pus or mucus may escape from the nostrils, 

 since in this position the fluid contents more readily reach the orifice. 



The naso-lacrimal duct which carries the tears into the nose opens into the front and upper 

 part of the inferior meatus under cover of the inferior concha. 



THE NECK 



The topics considered in the neck are the landmarks, thyreoid gland, sterno- 

 mastoid, clavicle, triangles and cervical ribs. 



Bony and cartilaginous landmarks. — The body of the hyoid is nearly on a 

 level with the angles of the jaw, and the interval between the third and fourth 

 cervical vertebrae (fig. 1097). With the head in the usual erect position it lies 

 a little higher than the chin. It divides the front of the neck into supra- and 

 infra-hyoid regions, convenient for remembering the distribution of the deep 

 fascia. On either side of the body are the great cornua, with the lesser cornua 

 attached to their upper borders at the junction with the body. The upper borders 

 of these are the guides to the lingual arteries. The outline and mobility of the 

 body and the great cornua are easily determined by relaxing the deep fascia and 

 pushing the bone over to the opposite side. Below the hyoid is the thyreo-hyoid 

 space, which corresponds with the ei)iglottis and the upper aperture of the 

 larynx. Thus, if the throat be cut above the hyoid, the mouth will be opened 

 and the tongue cut into; if the thyreo-hyoid space be cut, the pharynx would be 

 opened and the epiglottis wounded near its base. In the former case the lingual 

 and external maxillary are the most likely vessels to be wounded; in thyreo-hyoid, 

 the commonest cut-throat, the superior thyreoid vessels, and the superior laryn- 

 geal nerve. The projection of tiie thyreoid notch, about 2.5 cm. (1 in.) below 

 the hyoid, is much more distinct in men than in Avomen or children. It does 

 not appear before puberty, and thus flatness of the thyreoid must be expected 



