

SURFACE MARKINGS OF SPECIAL REGIONS OF HEAD AND NECK 1299 



With the laryngoscope many other structures can be seen. In the nasal part 

 of the pharynx (Fig. 1203), the choanse, the nasal septum, the nasal conchse, and 

 the pharyngeal ostia of the auditory tubes can all be examined. Further down, the 

 base of the tongue, the anterior surface of the epiglottis with the glossoepiglottic 

 and pharyngoepiglottic folds bounding the valleculae, and the piriform sinuses, are 

 readily distinguished. Beyond these is the entrance to the larynx, bounded on 

 either side by the aryepiglottic folds, in each of which are two rounded eminences 

 corresponding to the corniculate and cuneiform cartilages. 



Within the larynx (Fig. 1204) on either side are the ventricular and vocal folds 

 (false and true vocal cords) with the ventricle between them. Still deeper are 

 seen the cricoid cartilage and the anterior parts of some of the cartilaginous rings 

 of the trachea, and sometimes, during deep inspiration, the bifurcation of the 

 trachea. 



The Eye. The palpebral fissure is elliptical in shape, and varies in form in dif- 

 ferent individuals and in different races of mankind; normally it is oblique, in a 

 direction upward and lateral ward, so that the lateral commissure is on a slightly 

 higher level than the medial. When the eyes are directed forward as in ordinary 

 vision the upper part of the cornea is covered by the upper eyelid and its lower 

 margin corresponds to the level of the free margin of the lower eyelid, so that 

 usually the lower three-fourths are exposed. 



At the medial commissure (Fig. 1205) are the caruncula lacrimalis and the plica 

 semilunaris. When the lids are everted, the tarsal glands appear as a series of 

 nearly straight parallel rows of 

 light yellow granules. On the 

 margins of the lids about 5 mm. 

 from the medial commissure are 

 two small openings the lacrimal 

 puncta; in the natural condition 

 they are in contact with the con- 

 junctiva of the bulb of the eye, 

 so that it is necessary to evert 

 the eyelids to expose them. The 

 position of the lacrimal sac is indi- 

 cated by a little tubercle which 

 can be plainly felt on the lower 

 margin of the orbit; the sac lies 

 immediately above and medial to 

 the tubercle. If the eyelids be 

 drawn lateralward so as to tighten 

 the skin at the medial commissure 

 a prominent core can be felt be- 

 neath the tightened skin; this is the medial palpebral ligament, which lies over 

 the junction of the upper with the lower two-thirds of the sa"c, thus forming a 

 useful guide to its situation. The direction of the nasolacrimal duct is indicated 

 by a line from the lacrimal sac to the first molar tooth of the maxilla; the length 

 of the duct is about 12 or 13 mm. 



On looking into the eye, the iris with its opening, the pupil, and the front of the 

 !ens can be examined, but for investigation of the retina an ophthalmoscope is neces- 

 sary. With this the lens, the vessels of the retina, the optic disk, and the macula 

 lutea can all be inspected (Fig. 1206). 



On the lateral surface of the nasal part of the frontal bone the pulley of the 

 Obliquus superior can be easily reached by pushing the finger backward along the 

 roof of the orbit; the tendon of the muscle can be traced for a short distance back- 

 ward and lateralward from the pulley. 



Punetum tacrimale _J 



Plica semilunaris .^. '_J^ 



Caruncula 4j 



Pimctum lacrimale 



Openings of tarsal . 



glands 



FIG. 1205. Front of left eye with eyelids separated to show 

 medial canthus. 



