ANATOMICAL AND ENDOSCOPIC STUDIES OF THE EXTRACRANIAL INTERNAL CAROTID ARTERY IN THE HORSE

Routine endoscopy of the guttural pouches in neonatal foals occasionally shows atypical aspects of the extracranial internal carotid artery. On the contrary, such aspects are not observed in adult horses. In order to verify whether they can be attributable to the so-called dolichoarteriopathies described in humans (Beigelman et al., Angiology 61, 2010), an endoscopical investigation was carried out on 50 foals younger than 2 weeks of age and a dissection was performed on 15 horses of different age to expose, bilaterally, the internal carotid artery. Both the endoscopy and the anatomical study confirmed the presence of differently shaped internal carotid arteries in subjects aged less than one month. These anomalies were similar to the aspects belonging to the dolichoarteriopathies, and precisely, “tortuosity, kinking and coiling” (Weibel e Fields, Neurology 15, 1965). The presence of dolichoarteriopathies only in young animals together with the total absence in adults, prompt to consider these forms as a developmental stage of the arteries. The gradual lengthening of the neck and the caudally expansion of the guttural pouches cause a distension of the vessel and their acquisition of the definitive aspect. On the base of this hypothesis, tortuosity, kinking and coiling in foals should be considered a simple anatomical variability and not a pathological event.