[Cloquet's canal or Stilling's duct and Martegiani's space].

The vascular irrigation of the ocular globe during embryo development is carried out through the embryonary hyaloid artery (EHA)–a branch of the primitive dorsal ophthalmic artery–which, since the tenth week of gestation, progressively regresses and disappears at birth. In complete regression of said EHA gives rise to a number of intraocular structures which usually do not have clinic repercussion but could cause doubts in diagnostics and, in severe cases, lead to intraocular complications.1,2 Complete persistence of the embryo hyaloid artery after birth is very infrequent. Cloquet’s canal (CC) or Stilling’s duct (SD) is a transparent canal which traverses the vitriol and communicate the lens with the papilla during embryonary development. The rest of this canal or duct in the posterior lens capsule is known as the Mittendorf point and in the papilla, the Bergmeister papilla2 (BP). CC was described by the Parisian anatomist Jules-Germain Cloquet3 (1780–1883), a surgery professor who presented papers on pupil membrane and formation of the small arterial circle of the iris among others. In 1836, he published the Manual of Descriptive Anatomy of the Human Body which included extraordinary anatomic drawings.3 Subsequently, Jacob Stilling (1842–1915) studied said canal with different stains–such as Berlin blue–to clarify the structure and pathway of the canal in 1869. Born in Kassel (Germany), Stilling was a professor in Strassburg University and focused on studying the StillingTürk-Duane syndrome. Martegiani’s space (MS) was described in 1814 by Francesco Martegiani, a professor of medicine and surgery at Naples University. Among other works, Martegiani published the treatise Novae Observationes de Oculo Humano. The prepapillary section of the CC and MS can be appreciated in Fig. 1 in a nine-year old patient who visited for a routine checkup with absolutely normal results except this casual finding. Other structures that can be found in the posterior chamber are the Berger space, the Erggelet space or the Wieger ligament (Table 1 and Fig. 2). Although the persistence of these structures generally has no clinical importance, in severe forms it could be associated with primary vitreous persistence, cataracts of microphthalmos. Exceptionally, EHA can be found in its original structure which traverses the vitreous from the papilla toward the