THE MESOPTERYGIAL VEIN: A RELIABLE VENIPUNCTURE SITE FOR INTRAVASCULAR ACCESS IN BATOIDS

Intravascular access in batoid species is commonly achieved using the ventral coccygeal or radial wing vessels. However, these approaches can be difficult because of the presence of cartilage, lack of specific landmarks, species variation, and small vessel size in many species. This study used postmortem contrast radiography and gross dissection to develop landmarks for a new, dependable vascular access in three Myliobatiform species commonly maintained in captivity: Atlantic stingray (Hypanus sabinus), cownose ray (Rhinoptera bonasus), and smooth butterfly ray (Gymnura micrura). The mesopterygial vein provides quick vascular access and is suitable for administration of large fluid volumes and intravascular drugs. It is located immediately ventrolateral to the metapterygium cartilage, which sits adjacent to the coelomic cavity and supports the caudal half of the pectoral fin. Using the pectoral girdle and cranial third of the metapterygium cartilage as landmarks, vascular access can be achieved by directing a needle medially at approximately a 30° (adult cownose rays) or 45° angle (Atlantic stingrays, juvenile cownose rays, smooth butterfly rays) toward the metapterygium cartilage. Differences in the degree of needle direction are due to species and age-specific shapes of the metapterygium cartilage. The mesopterygial vein is an alternate site of quick and reliable venous access in batoid species.