770 



THE EAR. 



Kolliker that during the whole period of foetal life the tympanic cavity is occupied 

 by connective tissue, in which the ossicles are imbedded ; and that only after the 

 breathing process is commenced this tissue recedes before an expansion of the mucous 

 membrane. The pinna is gradually developed on the posterior margin of the first 

 branchial cleft. It is deserving of notice that congenital malformation of the external 

 ear, with occlusion of the meatus and greater or less imperfection of the tympanic 



Fig. 527. 



Fig. 527. VIEWS OF THE 

 CARTILAGE OP MECKEL 

 AND PARTS CONNECTED 

 WITH THE FIRST AND 

 SECOND BRANCHIAL 

 PLATES. 



A (after Kolliker), head 

 of a foetus of about eigh- 

 teen weeks, showing the 

 cartilage of Meckel in con- 

 nection with the malleus, 

 &c. M, the cartilage of 

 Meckel of the right side. 



B (from nature). An 

 enlarged sketch explana- 

 tory of the above view; z, 

 the zygomatic arch ; ma, 

 the mastoid process ; mi, 

 portions of the lower jaw 

 of which the parts near 

 the angle and the sym- 

 physis have been removed ; 

 M, the cartilage of Meckel 

 of the right side; M', a 

 small part of that of the 

 leftside, joiningthe left car- 

 tilage at s, the symphysis ; 

 T, the tympanic ring ; m, 

 the malleus ; i, the incus; 

 s, the stapes ; sta, the 

 stapedius muscle ; st, the 

 styloid process ; p, h, g, the 

 stylo -pharyngeus, stylo- 

 hyoid and stylo -glossus 

 muscles, st-l, stylo-hyoid 

 ligament attached to the 

 lesser cornu of the hyoid 

 bone ; hy, the hyoid bone ; 

 tk, thyroid cartilage. In 

 A, the head being turned 

 somewhat upwards, the 

 same parts are shown, to- 

 gether with the surround- 

 ing muscles, the carotid 

 artery, jugular vein, &c. 



apparatus, are observed in connection with abnormal development of the deeper 

 parts of the first and second branchial lappets and the intermediate cleft ; while cases 

 have been observed of the persistence in the neck of the adult of one or more of the 

 branchial clefts situated behind the first. (Allen Thomson, Proceed. Roy. Soc. of 

 Edin. 1844, and Edin. Journ. of Med. Sc. 1847.) 



