Ultrasonography-Guided Perineural Injection of the Ramus ventralis of the 7 and 8th Cervical Nerves in Horses: A Cadaveric Descriptive Pilot Study

International audienceObjective: To describe the feasibility and dye diffusion of selective perineural injection of the 7 and 8th cervical nerve (C7 and C8) ramus ventralis under ultrasonographic guidance in horses.Study design: Prospective experimental pilot cadaver study.Animals: Four equine cadavers of similar body weight (420-480 kg) and neck conformation.Methods: Five C7 and five C8 rami were perineurally injected with a dye solution. Anatomic dissections including vertebral canal opening were conducted to confirm nerve dye staining and describe the extent of color diffusion.Results: The ramus ventralis of the spinal cervical nerves was visualized in all cadavers. All the injections were successful in staining a portion of the nerve trunk. Eight rami had a uniform transversal staining of the nerve trunk that longitudinally covered a distance >2 cm. One C7 and one C8 nerve trunk showed incomplete transversal staining with a more concentrated color on its half cranial aspect and a longitudinal coverage of