28 DR. C. F. SONNTAG ON THE LARYNX AND 



conditions is unique, and raises problems for solution by tlie 

 embryologist and physiologist. The soft palate and the posterior 

 wall of the pharynx were divided in a vertical direction, but the 

 posterior wall of the oesophagus was only divided fi'om behind 

 forwards and above downwards till tlae mucous membrane 

 appeared. I did not divide any more, as I considered that it 

 was better to preserve the abnormality of the oesophagus entire. 

 In the normal state, however, the posterior wall of the oesophagus 

 was divided completely and the two halves thrown outwards. 

 By that means an uninterrupted view of the tongue, larynx, 

 pharynx, and oesophagus is obtained. 



In the normal state the epiglottis has a notched border and a 

 median fissure running vertically down the inner surface, so that 

 the cartilage appears to be composed of two symmetiical halves. 

 It slants upwards and forwards, and the upper aperture of the 

 larynx is small. The aryteno-epiglottidean folds, with their 

 contained cai'tilages of Wrisberg, are small, and appear globular. 

 The posterior surface of the larynx is smooth. 



In the abnormal specimen the epiglottic border is devoid of a 

 notch, and the cai'tilage stands up vertically, so that very little 

 of i1;s inner surface is visil)le. There is no vertical median 

 fissure on that surface, so that it appears like an arc of a circle. 

 The aperture of the larynx is capacious, and the aryteno-epiglottic 

 folds with their cartilages are oval ; they are more prominent 

 than in the normal condition. Indeed, the whole larynx appears 

 larger. Its postero-lateral aspects exhibit a number of ridges 

 and sulci running horizontally round the upper part and ter- 

 minating on a strong vertical median ridge. 



The oesophagus of the normal specimen appears as a wide space 

 behind the larynx. Its walls are ridged vei-tically, and an unin- 

 terrupted view of the back of the larynx, invested by transparent 

 mucous membrane, is obtained. 



In the abnormal specimen a broa,d ca,rtilaginous plate covers 

 up the whole of the laiynx below the pitcher-beak produced 

 by the arytenoid cartilages. It in turn is, with the exception of 

 its upper end, concealed by a vertical partition of mucous mem- 

 brane. It measures 1'5 cm. long, 1 mm. thick, and '75 cm. in 

 vertical height at its mid point, but it tapers towards its extre- 

 mities. It is convex backwards on its outer surface, and concave 

 backwards on its inner one. Its left extremity runs into the 

 end of a plate on the posterior surface of the larynx, but its right 

 end fuses with the posterior surface of the larynx beyond the 

 right extremity of the latter plate. As the anterior plate 

 is convex backwards, the two plates fit into one another, and the 

 orifice of the oesophagus is curved (text-fig. 3); it is tightly 

 closed. The anterior plate is not so high as the posterior one, 

 but extends further down the oesophagus, and is firmly adherent 

 to the cricoid cartilage. 



In text-fig. 5 a sagittal section has been made of the normal 

 neck, and the simplicity of the structures can be seen. It 



