Analysis of morphological variation of the internal ophthalmic artery in the chinchilla (Chinchilla laniger, Molina)

Abstract

ABSTRACT:The aim of this investigation was the analysis of the variability within the internal and external ophthalmic artery in the chinchilla (Chinchilla laniger, Molina). The head vasculature of 65 individuals was analysed, with particular emphasis on the internal ophthalmic artery originating from the central and rostral part of the cerebral arterial circle. Head blood vessels were filled with acrylic latex for vascular corrosion casting. The results showed ten variants of blood supply for the orbit, with a predominance of the first variant (66.1%) = bilateral presence of the external ophthalmic artery originating from the maxillary artery. Other variants differed in symmetry and asymmetry, sites of origination and the coexistence of both internal and external arteries. Vascularisation of the brain in chinchillas originates mainly from the vertebra-basilar system. The observed variability seems to confirm the role of the basilar artery in the arterial blood supply of the brain in this species.

Morphometry and Variability of the Brain Arterial Circle in Chinchilla (Chinchilla laniger, Molina)

“…In chinchillas, the organization of the circle of Willis is comparable with other rodents (porcupine, nutria, dormouse, squirrel) in whom the ICA was obliterated and the cerebral brain supply originates mainly from the basilar artery (BA) (Kuchinka, 2015, Brudnicki et al, 2015, Ara ujo and Campos 2005, Aydin et al, 2005, Bugge 1971). According to Gielecki et al (1996), appropriate geometrical parameters of ACBr may be sufficient for adequate arterialization of the brain by BA alone, even in absence of other sources of inflowing blood (ICA or internal ophthalmic artery).…”

“…VAs are principally the only source of cerebral blood supply in rodents such as nutria (Azambuja ), chinchilla (Araújo and Campos , Kuchinka ), or porcupine (Aydin et al, ). The reported asymmetry of VA in chinchillas pertained mainly to the diameter of vessels.…”

“…The vessels originated both from the terminal branches of the basilar artery, both symmetrically and separately on the left and on the right, and as symmetrical or unilateral double vessels. No descriptions were found in the literature to be similar to the case of chinchillas, where IOAs may be the only vessels supplying blood to the eyeballs (Kuchinka ). Some degree of IOA variability in chinchillas was also described in Araújo and Campos ().…”

“…Studies allowing for the determination of organization, distribution, and potential differences in the blood vessels within the base of the brain may also provide a contribution to the phylogenesis and ontogenesis of cerebral arteries (Bugge ). Arterial cerebral blood supply was described mainly by Araújo and Campos (), Jabłoński and Brudnicki (), Roskosz et al, (), Gielecki et al, (), and Kuchinka (). The Chinchilidae— in a manner similar to Hystricidae, Cavidae, Hydrochoeridae, Dasyproctidae , and Myocastoridae —are characterized by the obliterated extracranial part of the internal carotid artery (ICA) (Frąckowiak ).…”

The Stapedial Artery in the Mongolian Gerbil (Meriones unguiculatus)

“…Under these circumstances, the external ophthalmic artery becomes a branch of the maxillary artery and is sometimes assisted by very well-developed internal ophthalmic arteries extending from the rostral part of the circle of Willis. A special characteristic and the high variability of the arterial blood supply of the orbit was described by Kuchinka (2015Kuchinka ( , 2017 in chinchillas, and by Ocal and Ozer (1992) in guinea pigs. In humans, Hayreh and Dass (1962) demonstrated several cases of the eyeball supply originating from the middle meningeal artery, while Bervini and Assaad (2014) described a case of the ophthalmic artery branching off from the anterior cerebral artery in humans.…”