30 THE SUSPENSOBY LIGAMENT. [BOOK in. 



inelastic membrane, the suspensory ligament (Fig. 134) is attached 

 to and becomes fused with the capsule of the lens on the anterior 

 surface of that body. 



During life the vitreous humour is in contact not only with the 

 posterior surface of the lens, but also with the back surface of the 

 suspensory ligament. After death, however, through changes in 

 the vitreous humour, a space is developed, of a triangular form in 

 section, between the suspensory ligament in front, the lens on the 

 inside and the vitreous humour behind ; this is often spoken of as 

 the canal of Petit. According to some authors this canal exists 

 during life and possesses a hind wall which is furnished by a 

 membrane, distinct from the hyaloid membrane or suspensory 

 ligament, which defines the front of the vitreous humour; and 

 if, as asserted, the capsule of the lens be imperfect behind ( 719), 

 something of the nature of a membrane must exist in the front 

 of the vitreous humour, since, when the lens is, in extraction of 

 cataract, removed from the capsule, the vitreous humour does 

 not escape into the vacant cavity. Since the suspensory ligament 

 is attached on the outside, alternately to a projecting ciliary 

 fold and to the depression between that and the next fold, the 

 canal of Petit, when distended with air by blowing into it, has 

 a beaded appearance. When the canal is thus blown out the 

 suspensory ligament and its attachments are rendered very 

 obvious ; the ring thus formed by the suspensory ligament around 

 the lens is sometimes called the zonule of Zinn. 



We shall deal with the aqueous humour in speaking of the 

 lymphatics of the eye. 



